Bio


Howard’s research group specializes in interferometric radar remote sensing applications and technique development, as applied to studies of the Earth and solar system. Originally a microwave engineer, he built support equipment for the SEASAT satellite synthetic aperture radar and designed airborne radar systems. He later developed imaging radar polarimetry, a technique for measurement of the radar scattering matrix of a surface. He is best known for the development of radar interferometry, leading to spaceborne and airborne sensors capable of measuring topography to meter scale accuracy and surface deformation to mm scale. More recently he has been participating in the NASA Cassini Mission to Saturn, concentrating on analysis of data acquired by the radar/radiometer instrument. He is a Fellow of the AGU, IEEE, and Electromagnetics Academy. He has served on a number of National Academy panels, mostly for the Space Studies Board, plus the Naval Studies Board Advanced Radar Technology Panel. He holds a joint appointment with the Department of Electrical Engineering at Stanford, where he serves as Associate Chair for admissions

Academic Appointments


Administrative Appointments


  • Distinguished Visiting Scientist, NASA Jet Propulsion Laboratory (2021 - 2022)
  • Visiting Faculty, California Institute of Technology (2021 - 2022)
  • Distinguished Visiting Scientist, NASA Jet Propulsion Laboratory (2019 - 2020)
  • Visitor, California Institute of Technology (2019 - 2020)
  • Chair, Department of Geophysics, Stanford University (2013 - 2019)
  • Associate Chair, Admissions, Department of Electrical Engineering, Stanford University (2008 - Present)
  • Professor of Geophysics and Electrical Engineering, Stanford University (2006 - Present)
  • Associate Professor Electrical Engineering and Geophysics, Stanford University (1995 - 2006)
  • Assistant Manager Radar Science and Engineering Section, Jet Propulsion Lab (1984 - 1995)
  • Postdoctoral Research Affiliate Electrical Engineering, Stanford University (1984 - 1984)
  • Member Technical Staff, Radar Science and Engineering Section, Jet Propulsion Laboratory (1976 - 1980)
  • Research Assistant, Physics Section, Jet Propulsion Laboratory (1975 - 1976)

Honors & Awards


  • Group Achievement Award, Seasat-A-Synthetic Aperture Radar Team, NASA (1979)
  • Group Achievement Award, Shuttle Imaging Radar (SIR-A) Development Team, NASA (1982)
  • U.S. Patent No. 4,450,447: Synthetic Aperture Radar Target Simulator, U.S. Patent Office (1984)
  • NASA Certificates of Achievement: New Technology: Approaches to modelling polarization..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Mapping small elevation changes..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Phase calibration of imaging radar..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Radar imaging polarimetry, NASA (1988-1995)
  • Certificates of Achievement for New Technology: Preliminary silutaneous L/C-band images..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: radar polarimeter measures orientation..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Data volume reduction for imaging radar polarimetry, NASA (1988-1995)
  • Certificates of Achievement for New Technology: Synthetic aperture radar processor..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Interferometric radar measurement..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Topographic mapping from interferometric..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Imaging radar polarimeter, NASA (1988-1995)
  • Certificates of Achievement for New Technology: Software for polarimetric radar analysis..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Calibration of Stokes and scattering mattrix..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: Topographic mapping using radar interferometr..., NASA (1988-1995)
  • Certificates of Achievement for New Technology: THE TOPSAR interferometric radar..., NASA (1988-1995)
  • Director's Research Achievement Award, Jet Propulsion Laboratory (1988)
  • Best paper award, IEEE Geoscience and Remote Sensing Society (1988)
  • U.S. Patent No. 4, 829,303: Data Volume Reduction for Imaging Radar Polarimetry, U.S. Patent Office (1989)
  • U.S. Patent No. 4, 975,704: Method for Detecting Surface Motions and Mapping Small Terrestrial..., U.S. Patent Office (1990)
  • Group Achievement Award, Airborne Imaging Radar System Team, NASA (1990)
  • Best paper award, IEEE Geoscience and Remote Sensing Society (IGARSS 95) (1995)
  • Dana Adams Griffin Award, School of Engineering, Stanford University (1998)
  • Fellow, Institute of Electrical and Electronics Engineers (1998)
  • Best reviewer award, IEEE Transactions on Geoscience and Remote Sensing (1999)
  • Robert Noyce Faculty Scholar, Stanford University School of Engineering (1999)
  • Fellow, The Electromagnetics Academy (1999)
  • Award for New Technology Report no. 20376: "ROI (Repeat Orbit Interferometer) Software.", NASA Board (2006)
  • Certificate of Recognition for development of Differential Radar Interferometry, June, NASA (2007)
  • Technical Brief Achievement Award, Airborne Radar Interferometric Repeat Pass Processing, NASA (2010)

Boards, Advisory Committees, Professional Organizations


  • Chair, EE Ph.D. Program Committee, Stanford University (1996 - 2003)
  • EE Admissions Committee (co-Chair 2005-7), Stanford University (1997 - 2003)
  • Freshman advisor, Stanford University (1997 - 2003)
  • LightSAR Science Working Group, NASA (1997 - 1999)
  • Associate Editor, IEEE Transactions on Geoscience and Remote Sensing (1998 - 2009)
  • Europa Radar Instrument Definition Team, NASA (1998 - 1999)
  • Alaska SAR Facility Users Working Group, NASA (1998 - Present)
  • Invited Speaker:, Phase unwrapping algorithms for radar interferometry: residue/cut, least-squares, and synthesis algorithms, 1998 Progress in Electromagnetic Research Symposium (PIERS '98), July 13-17, Nantes, France (1998 - 1998)
  • Invited Speaker, Volume scattering effects in radar interferograms: foliage and icy targets, 1998, Progress in Electromagnetic Research Symposium (PIERS '98), July 13-17, Nantes, France (1998 - 1998)
  • Invited Speaker, Interferometric radar measurement of the viscosity of salt near the Dead Sea, IGARSS 98, International Geoscience and Remote Sensing Symposium, July 6-10, Seattle, Washington (1998 - 1998)
  • Invited Speaker, Contributions to Earth Crustal Deformation Studies from Interferometric Synthetic Aperture Radar, AGARSS 98: International Geoscience and Remote Sensing Symposium, July 6-10, Seattle, Washington (1998 - 1998)
  • Invited speaker, Measuring Earth Crustal Deformation with Interferometric Synthetic Aperture Radar,AAAS Annual Meeting and Science Innovation Exposition, Feb. 12-17, Philadelphia, Pennsylvania (1998 - 1998)
  • Geophysics Department graduate program coordinator, Stanford University (1998 - 2005)
  • EE Search Committee for Digital Image and Video Systems, Stanford University (1998 - 1999)
  • EE Search Committee for Medical Imaging Systems, Stanford University (1999 - 2000)
  • Invited speaker, On the use of radar interferometry for volcano geodesy, AGU meeting, San Francisco (1999 - 1999)
  • Invited speaker, Studying volcanoes using interferometric synthetic aperture radar, Cascades Volcano Observatory (1999 - 1999)
  • Invited speaker, Imaging the subsurface with spaceborne interferometric radar, Scripps Inst. of Oceanography IGPP Geophysics Seminar series, SIO, April 27, 1999 (1999 - 1999)
  • Invited speaker, Using subaperture processing and interferometric correlation measurements to infer subsurface scattering properties, International Geoscience and Remote Sensing Symposium, June 28 -July 2, 1999, Hamburg, Germany (1999 - 1999)
  • Invited speaker, Advances in interferometric phase unwrapping: network flow algorithms, International Geoscience and Remote Sensing Symposium, June 28 -July 2, 1999, Hamburg, Germany (1999 - 1999)
  • Invited speaker, Imaging subsurface fluid flow using spaceborne interferometric radar, URSI XXVI General Assembly, August 13-21, 1999, Toronto, Canada (1999 - 1999)
  • Technical committee member, Progress in Electromagnetic Research Symposium, (PIERS 2000) (1999 - 2000)
  • Invited speaker, Speculating on radar volcanology in the coming decade, AGU (Fall) | Meeting, San Francisco, CA (2000 - 2000)
  • Invited speaker, Inference of volcano subsurface processes from InSAR crustal deformation observations, Third Joint Meeting, U.S.-Japan Natural Resources Panel on Earthquake Research, USGS, Menlo Park, CA (2000 - 2000)
  • Invited speaker, We don't need a new InSAR mission, Proceedings of the International Geoscience and Remote Sensing Sensing Symposium, Honolulu, Hawaii (2000 - 2000)
  • Invited speaker, Subsurface volcanic processes in the Galapagos Islands from interferometric SAR, Progress in Electromagnetics Research Symposium 2000 (PIERS) Cambridge, Mass. (2000 - 2000)
  • Invited speaker, Radar science and technology:speculating on the next 20 year, Workshop on Scientific Applications of Synthetic Aperture Radar (SAR) Satellites, USC (2000 - 2000)
  • Session Chair, Interferometric and Differential Interferometric SAR, International Geoscience and Remote Sensing Symposium, Honolulu, Hawaii (2000 - 2000)
  • Member, Solid Earth Science Proposal Review Panel, NASA Earth Science Enterprise (2000 - 2000)
  • Member, Earth Science Technology Office (ESTO), NASA Earth Science Enterprise, Advanced Radar Technology Panel (2000 - 2000)
  • Steering Committee and Earthquake Working Group, NSF Workshop on Scientific Applications of Synthetic Aperture Radar, University of Southern California (2000 - 2000)
  • Technical Program Committee, 2001 Progress In Electromagnetic Research Symposium (2001 - 2001)
  • Executive Committe member, Chair (2004-6),Vice Chair (2002-3), Western North America Interferometric SAR (Winsar) consortium, a division of the Southern California Earthquake Center, national Science Foundation (2001 - 2008)
  • Antarctic Mapping Mission (AMM) Science Advisory Group, NASA (2001 - 2001)
  • Summer Research Workshop, Synergies in Geophysical, Medical and Space Imaging, July 22- 26, Newport Beach, California (2001 - 2001)
  • Invited speaker, Time-Lapse Imaging of Subsurface Flow Using SAR Interferometry, SEG (2001 - 2001)
  • Invited speaker, Measuring Earth Crustal Deformation With Interferometric Synthetic Aperture Radar, Xerox Palo Alto Research Center Forum, February 1, 2001. (2001 - 2001)
  • Invited speaker, Measuring Earth Crustal Deformation with Interferometric Synthetic Aperture Radar, University of California, Santa Barbara, Dept.of Geology Lecture Series, Santa Barbara, CA, Feb. 28 (2001 - 2001)
  • Invited speaker, Measuring Subsurface Flow with Interferometric Synthetic Aperture Radar, UC Davis Hydrology Seminar Series, University of California at Davis, January 18 (2001 - 2001)
  • Session chair and organizer, Geophysical Modeling Using Spaceborne InSAR Measurements, American Geophysical Union 2002 (Fall) | Meeting, 6-10 December, 2002, San Francisco, CA. (2002 - 2002)
  • Technical Program Committee, 2002 Progress In Electromagnetic Research Symposium (2002 - 2002)
  • Solid Earth Science Proposal Review Panel, NASA Earth Science Enterprise (2002 - 2002)
  • Chair, Visiting Committee, NSF National Astronomy and Ionosphere Center (Arecibo Observatory) (2002 - 2004)
  • Chair (2003-5), University Senate Committee on Review of Undergraduate majors (C-RUM), Stanford University (2002 - 2005)
  • Chair, Geophysics Department Curriculum Committee, Stanford University (2003 - 2005)
  • Chair, George A. Thompson Fellowship Committee, Department of Geophysics, Stanford University (2003 - 2003)
  • Search committee, Surface Processes, Dept. of Geological and Environmental Sciences, Stanford University (2003 - 2004)
  • School of Earth Sciences Committee on Computational Geosciences, Stanford University (2003 - 2004)
  • Technical Program Committee, Progress in Electromagnetics Research Symposium (2003 - 2003)
  • Invited keynote talk, Time-dependent deformation associated with natural hazards, 30th International Symposium on Remote Sensing of the Environment, Nov. 10-14, 2003, Honolulu, Hawaii. (2003 - 2003)
  • Invited Speaker, General Assembly, June 30-July 11, 2003, Sapporo, Japan. (2003 - 2003)
  • Invited speaker, 4-d imaging of the Earth's subsurface using insar: moving beyond the single interferogram, International Union of Geodesy and Geophysics (IUGG) (2003 - 2003)
  • Solid Earth Science Proposal Review Panel, NASA Earth Science Enterprise (2003 - 2003)
  • Technical Committee, Progress in Electromagnetics Research Symposium 2003, October 13-16, 2003, Honolulu, Hawaii (2003 - 2003)
  • Steering Committee, InSAR Working Group (2004 - Present)
  • NASA Review Committee, Earth System Science Fellowships (2004 - 2004)
  • NASA Technical Review Committee, HICP planetary missions (2004 - 2004)
  • Organizing Committee, Interagency Interferometric Synthetic Aperture Radar Workshop (2004 - 2004)
  • Member, International Union of Radioscience (URSI) Board of Experts for Medal Evaluations (2004 - 2005)
  • chool of Earth Sciences Committee on Establishment of a School-wide Undergraduate major, Stanford University (2004 - 2005)
  • Department of Electrical Engineering Qualification Examination Appeals Committee, Stanford University (2004 - 2006)
  • Chair, Dept. of Geophysics Admissions Committee, Stanford University (2005 - 2011)
  • Board of Experts, International Union of Radioscience (URSI) for Medal Evaluations (2005 - 2005)
  • Earth Science Technology Office Review Panel, NASA (2005 - 2005)
  • NASA Review Committee, Earth System Science Fellowships (2005 - 2006)
  • Editorial Board, Proceedings of the IEEE (2005 - Present)
  • NRC Earth Science and Applications Panel, NASA Earth Science Decadal Survey (2005 - 2007)
  • Invited talk, Zebker, H.A., Research Within the WInSAR Consortium, Eos Trans. AGU, 87(52), (Fall) Meet. Suppl., Abstract H24C-02 (2006 - 2006)
  • NASA Review Committee, Earth System Science Fellowships (2006 - Present)
  • NASA, Earth Science Technology Office Review Panel (2006 - Present)
  • InSAR Review Board, NASA Jet Propulsion Laboratory (2006 - Present)
  • Invited talk, Zebker, H.A., Research Within the WInSAR Consortium, Eos Trans. AGU, 87(52), (Fall) | Meet. Suppl., Abstract H24C-02 (2006 - 2006)
  • Member, International Program Committee, International Association of Science and Technology for Development (IASTED), International Conference on Antennas, Radar, and Propagation (2006 - 2007)
  • Session chair, InSAR Science Results and Recommendations for Future Missions I, II, and III, 2006 American Geophysical Union (Fall) | Meeting, San Francisco, Dec. 10-15 (2006 - 2006)
  • Technical Program Committee, IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2006), Denver, CO, Jul. 31 – Aug. 4 (2006 - 2006)
  • Session chair, Geological Hazards. 2006 IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2006), Denver, CO (2006 - 2006)
  • Participating Scientist Review Committee, NASA Mars Reconnaissance Orbiter (2006 - 2006)
  • Session Chair, Remote Sensing and Imaging, 2006 Progress in Electromagnetics Research Symposium, Cambridge, MA., March 26-29 (2006 - 2006)
  • Session Chair, Microwave Remote Sensing of Snow, 2006 Progress in Electromagnetics Research Symposium, Cambridge, MA., March 26-29 (2006 - 2006)
  • Chair, Faculty Senate Committee for Review of Undergraduate Majors (C-RUM), Stanford University (2006 - 2006)
  • Chair, Geophysics Department George Thompson Fellowship Committee, Stanford University (2006 - 2007)
  • Chair, Board of Judicial Affairs, Stanford University (2007 - 2009)
  • Broad Area Search Committee, Dept. of Electrical Engineering, Stanford University (2007 - 2008)
  • Steering Committee, NSF EarthScope (2007 - 2011)
  • Invited talk, Zebker, H.A., and P. Shankar, InSAR Remote Sensing Over Decorrelating Terrains: Persistent Scattering Methods, RADAR Littoral Studies Workshop, Naval Postgraduate School, Monterey Bay Aquarium Research Institute (MBARI), Moss Landing, California, August 9 (2007 - 2007)
  • Invited talk, Zebker, H.A, Radar Measurements: electrical properties of Titan and constraints on surface composition and structure, CIPS Titan Workshop II: Titan after Cassini, UC Berkeley, Berkeley, CA, May 15 (2007 - 2007)
  • Invited talk, Zebker, H.A, Titan’s Surface from Reconciled Cassini Microwave Reflectivity and Emissivity Observations, UCSD Scripps Institution of Oceanography Institute for Geophysics and Planetary Physics Seminar, UC San Diego, La Jolla, CA, April 27 (2007 - 2007)
  • Invited talk, Zebker, H.A., Accomplishments in Earth science from satellite observations, National Research Council Committee on Scientific Accomplishments of Earth Observations from Space, Irvine, CA, March 5 (2007 - 2007)
  • Session chair, InSAR Science Results and Recommendations for Future Missions I, II, and III, 2006 American Geophysical Union (Fall) | Meeting, San Francisco, Dec. 10-15 (2007 - 2007)
  • Member, International Program Committee, International Association of Science and Technology for Development (IASTED), International Conference on Antennas, Radar, and Propagation 2007 (ARP 2007), Montreal, Canada, May 30th - June 1 (2007 - 2007)
  • Editor and Chair, Editorial Committee, Report of the July 17-19, 2007 Orlando, Florida Workshop to Assess the National Research Council Decadal Survey Recommendation for the DESDynI Radar/Lidar Space Mission (2007 - 2007)
  • Invited speaker, Zebker, H.A., and A.P. Shanker (2008), Geodetic imaging with time series persistent scatterer InSAR, Eos Trans. AGU, 89 (53), (Fall) | Mtg. Suppl., Abstract G51C-02 (2008 - 2008)
  • Executive Committee, Department of Electrical Engineering (2008 - Present)
  • Member, USEReST Program Committee, for meeting in Naples, It. Nov. (2008 - 2008)
  • Chair, EE Graduate Admissions Committee, Stanford University (2008 - Present)
  • Chair, Committee on Academic Computing and Information Systems (C-ACIS), Stanford University (2009 - 2012)
  • Faculty Search Committee, Dept. of Aeronautics and Astronautics, School of Engineering, Stanford University (2010 - 2011)
  • Team Leader, School of Earth Sciences Initiative on Computational Earth Sciences, Stanford University (2010 - 2011)
  • Session Chair, Remote Sensing and Polarimetry: SAR, GPR, Imaging, at Progress in Electromagnetics Research Symposium (PIERS 2010), Cambridge. MA, July 5-8 (2010 - 2010)
  • Session Chair, Sensors and Platforms- SAR Processing: Interferometric SAR Processing Thursday, July 29, 08:20 - 10:00, 2010 IEEE International Geoscience and Remote Sensing Symposium, Honolulu, HI, July 25-30 (2010 - 2010)
  • International Program Committee, International Association of Science and Technology for Development (IASTED), International Conference on Antennas, Radar, and Propagation (2009 - Present)
  • Steering Committee, National Science Foundation EarthScope Program Science (2007 - 2011)
  • Chair, Nominations Subcommittee, EarthScope Science Steering Committee (2010 - 2011)
  • Organizing Committee, EarthScope National Meeting (2010 - 2010)
  • Invited talk, Zebker, H. A. (2010), InSAR Volcanology 2010: the Past and Coming Decade, Abstract V44C-02, presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec. (2010 - 2010)
  • Invited talk, Zebker, H.A., Measuring Earth's Crustal Deformation Using InSAR, 2011 Symposium on Position, Navigation, and Time, Stanford Linear Accelerator Center, Nov. 17 (2011 - 2011)
  • Invited talk, Zebker, H.A., C. Wortham, J. Lien, and P.S. Agram (2011), Advances in time-series InSAR, Eos Trans. AGU, 92(52), Fall Meet. Suppl., Abstract G21C-03 (2011 - 2011)
  • Steering Committee, NASA DESDynI (Deformation, Ecosystems, and Dynamics of Ice) Science (2008 - Present)
  • Technical Review Committee, IEEE Geoscience and Remote Sensing Symposium (2009 - Present)
  • Panel on Sustainable Land Imaging, National Research Council (2011 - Present)
  • Geodetic Imaging Panel, NASA (2011 - 2012)
  • Member, NASA DESDynI Science Definition Team (2012 - 2013)
  • Member, NASA Earth Science Technology Office Review Panel (2012 - 2013)
  • Member, NASA Review Committee, Earth System Science Fellowships (2012 - 2013)
  • Session convener and co-Chair, Exotic and Unusual Applications of Geodesy, AGU Fall Meeting (2012 - 2012)
  • Panel on the US Land Imaging Program, National Research Council (2012 - 2013)
  • Associate Chair, Dept. of Geophysics, Stanford University (2012 - Present)
  • Promotion Committee, Tiziana Vanorio, Geophysics, Stanford University (2012 - 2012)
  • Team Leader, Geophysics Strategic Planning Leadership Committee, Stanford University (2013 - 2013)

Professional Education


  • PhD, Stanford University (1984)
  • M.S., University of California at Los Angeles, Engineering (1979)
  • B.S., California Institute of Technology, Engineering and Applied Science (1976)

Current Research and Scholarly Interests


Research
My students and I study the surfaces of Earth and planets using radar remote sensing methods. Our specialization is interferometric radar, or InSAR. InSAR is a technique to measure mm-scale surface deformation at fine resolution over wide areas, and much of our work follows from applying this technique to the study of earthquakes, volcanoes, and human-induced subsidence. We also address global environmental problems by tracking the movement of ice in the polar regions. whose ice mass balance affects sea level rise and global climate. We participate in NASA space missions such as Cassini, in which we now are examining the largest moon of Saturn, Titan, to try and deduce its composition and evolution. Our work includes experimental observation and modeling the measurements to best understand processes affecting the Earth and solar system. We use data acquired by spaceborne satellites and by large, ground-based radar telescopes to support our research.

Teaching
I teach courses related to remote sensing methods and applications, and how these methods can be used to study the world around us. At the undergraduate level, these include introductory remote sensing uses of the full electromagnetic spectrum to characterize Earth and planetary surfaces and atmospheres, and methods of digital image processing. I also teach a freshman and sophomore seminar course on natural hazards. At the graduate level, the courses are more specialized, including the math and physics of two-dimensional imaging systems, plus detailed ourses on imaging radar systems for geophysical applications.

Professional Activities
InSAR Review Board, NASA Jet Propulsion Laboratory (2006-present); editorial board, IEEE Proceedings (2005-present); NRC Earth Science and Applications from Space Panel on Solid Earth Hazards, Resources, and Dynamics (2005-present); Chair, Western North America InSAR (WInSAR) Consortium (2004-06); organizing committee, NASA/NSF/USGS InSAR working group; International Union of Radioscience (URSI) Board of Experts for Medal Evaluations (2004-05); National Astronomy and Ionospheric Center, Arecibo Observatory, Visiting Committee, (2002-04; chair, 2003-04); NASA Alaska SAR Facility users working group (2000-present); associate editor, IEEE Transactions on Geoscience and Remote Sensing (1998-present); fellow, IEEE (1998)

2023-24 Courses


Stanford Advisees


All Publications


  • Rapid beamforming of ultrasound chirp signals in frequency domain using the chirp scaling algorithm Zhuang, L. L., Dahl, J., Zebker, H., Jakovljevic, M. ACOUSTICAL SOC AMER AMER INST PHYSICS. 2023

    View details for DOI 10.1121/10.0018774

    View details for Web of Science ID 001000287901325

  • Permafrost Dynamics Observatory (PDO): 2. Joint Retrieval of Permafrost Active Layer Thickness and Soil Moisture From L-Band InSAR and P-Band PolSAR EARTH AND SPACE SCIENCE Chen, R. H., Michaelides, R. J., Zhao, Y., Huang, L., Wig, E., Sullivan, T. D., Parsekian, A. D., Zebker, H. A., Moghaddam, M., Schaefer, K. M. 2023; 10 (1)
  • Adaptation of Range-Doppler Algorithm for Efficient Beamforming of Monostatic and Multistatic Ultrasound Signals. IEEE transactions on ultrasonics, ferroelectrics, and frequency control Jakovljevic, M., Michaelides, R., Biondi, E., Hyun, D., Zebker, H., Dahl, J. 2022; PP

    Abstract

    Algorithmic changes that increase beamforming speed have become increasingly relevant to processing synthetic aperture (SA) ultrasound data. In particular, beamforming SA data in a spatio-temporal frequency domain using F-k (Stolt) migration has been shown to reduce beamforming time by up to two orders of magnitude compared to conventional delay-and-sum (DAS) beamforming, and it has been used in applications where large amounts of raw data make real-time frame rates difficult to attain, such as multistatic SA imaging and plane-wave Doppler imaging with large ensemble lengths. However, beamforming signals in a spatio-temporal Fourier space can require loading large blocks of data at once, making it memory intensive and less suited for parallel (i.e. multi-threaded) processing. As an alternative, we propose beamforming in a range-Doppler (RD) frequency domain using the range-Doppler algorithm (RDA) that has originally been developed for SA radar imaging. Through simulation and phantom experiments we show that RDA achieves similar lateral resolution and contrast compared to DAS and F-k migration. At the same time, higher axial sidelobes in RDA images can be reduced via (temporal) frequency binning. Like F-k migration, RDA significantly reduces the overall number of computations relative to DAS, and it achieves ten times lower processing time on a single CPU. Because RDA utilizes only a spatial Fourier Transform, it requires two times less memory than F-k migration to process the simulated multistatic data, and can be executed on as many as a thousand parallel threads (compared to eight parallel threads for F-k migration), making it more suitable for implementation on modern graphics processing units (GPUs). While RDA is not as parallelizable as DAS, it is expected to hold a significant speed advantage on devices with moderate parallel processing capabilities (up to several thousand cores), such as point-of-care and low-cost ultrasound devices.

    View details for DOI 10.1109/TUFFC.2022.3205923

    View details for PubMedID 36094975

  • Volcano geodesy using InSAR in 2020: the past and next decades BULLETIN OF VOLCANOLOGY Poland, M. P., Zebker, H. A. 2022; 84 (3)
  • InSAR Time-Series Analysis With a Non-Gaussian Detector for Persistent Scatterers IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING Huang, S. A., Zebker, H. A. 2022; 15: 9208-9225
  • HIGH-RESOLUTION MEASUREMENT OF SOIL MOISTURE FROM INSAR PHASE CLOSURE Wig, E., Michaelides, R., Zebker, H., IEEE IEEE. 2022: 919-922
  • APPLYING THE CHIRP SCALING ALGORITHM FOR EFFICIENT BEAMFORMING OF ULTRASOUND IMAGES Zhuang, L., Dahl, J., Zebker, H., Jakovljevic, M., IEEE IEEE. 2022: 3011-3014
  • PLANNED DIFFERENTIAL INTERFEROMETRIC SAR OBSERVATIONS AT VENUS BY THE VERITAS MISSION Hensley, S., Wallace, M. S., Martin, J., Perkovic-Martin, D., Smrekar, S., Younis, M., Lachaise, M., Prats, P., Rodriguez, M., Zebker, H., Campbell, B., Mastrogiuseppe, M., IEEE IEEE. 2022: 12-15
  • A New Decorrelation Phase Covariance Model for Noise Reduction in Unwrapped Interferometric Phase Stacks IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Zheng, Y., Zebker, H., Michaelides, R. 2021; 59 (12): 10126-10135
  • Validation of Permafrost Active Layer Estimates from Airborne SAR Observations REMOTE SENSING Parsekian, A. D., Chen, R. H., Michaelides, R. J., Sullivan, T. D., Clayton, L. K., Huang, L., Zhao, Y., Wig, E., Moghaddam, M., Zebker, H., Schaefer, K. 2021; 13 (15)

    View details for DOI 10.3390/rs13152876

    View details for Web of Science ID 000682348200001

  • A Signal Model for PRF Dithering in Wide-Swath, Fine-Resolution InSAR IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Zebker, H. A. 2021; 18 (7): 1214-1218
  • Permafrost Dynamics Observatory-Part I: Postprocessing and Calibration Methods of UAVSAR L-Band InSAR Data for Seasonal Subsidence Estimation. Earth and space science (Hoboken, N.J.) Michaelides, R. J., Chen, R. H., Zhao, Y., Schaefer, K., Parsekian, A. D., Sullivan, T., Moghaddam, M., Zebker, H. A., Liu, L., Xu, X., Chen, J. 2021; 8 (7): e2020EA001630

    Abstract

    Interferometric synthetic aperture radar (InSAR) has been used to quantify a range of surface and near surface physical properties in permafrost landscapes. Most previous InSAR studies have utilized spaceborne InSAR platforms, but InSAR datasets over permafrost landscapes collected from airborne platforms have been steadily growing in recent years. Most existing algorithms dedicated toward retrieval of permafrost physical properties were originally developed for spaceborne InSAR platforms. In this study, which is the first in a two part series, we introduce a series of calibration techniques developed to apply a novel joint retrieval algorithm for permafrost active layer thickness retrieval to an airborne InSAR dataset acquired in 2017 by NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar over Alaska and Western Canada. We demonstrate how InSAR measurement uncertainties are mitigated by these calibration methods and quantify remaining measurement uncertainties with a novel method of modeling interferometric phase uncertainty using a Gaussian mixture model. Finally, we discuss the impact of native SAR resolution on InSAR measurements, the limitation of using few interferograms per retrieval, and the implications of our findings for cross-comparison of airborne and spaceborne InSAR datasets acquired over Arctic regions underlain by permafrost.

    View details for DOI 10.1029/2020EA001630

    View details for PubMedID 34435080

    View details for PubMedCentralID PMC8365676

  • Permafrost Dynamics Observatory-Part I: Postprocessing and Calibration Methods of UAVSAR L-Band InSAR Data for Seasonal Subsidence Estimation EARTH AND SPACE SCIENCE Michaelides, R. J., Chen, R. H., Zhao, Y., Schaefer, K., Parsekian, A. D., Sullivan, T., Moghaddam, M., Zebker, H. A., Liu, L., Xu, X., Chen, J. 2021; 8 (7)
  • Active layer thickness as a function of soil water content ENVIRONMENTAL RESEARCH LETTERS Clayton, L. K., Schaefer, K., Battaglia, M. J., Bourgeau-Chavez, L., Chen, J., Chen, R. H., Chen, A., Bakian-Dogaheh, K., Grelik, S., Jafarov, E., Liu, L., Michaelides, R., Moghaddam, M., Parsekian, A. D., Rocha, A., Schaefer, S. R., Sullivan, T., Tabatabaeenejad, A., Wang, K., Wilson, C. J., Zebker, H. A., Zhang, T., Zhao, Y. 2021; 16 (5)
  • Accuracy of a Model-Free Algorithm for Temporal InSAR Tropospheric Correction REMOTE SENSING Zebker, H. 2021; 13 (3)

    View details for DOI 10.3390/rs13030409

    View details for Web of Science ID 000615466900001

  • Backscatter Distributions of Persistent and Distributed Scatterers Over Wavelength: Results From X-, C-, and L-Band IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING Huang, S., Zebker, H. A. 2020; 13: 5518–25
  • A PHYSICS-BASED DECORRELATION PHASE COVARIANCE MODEL FOR EFFECTIVE DECORRELATION NOISE REDUCTION IN INTERFEROGRAM STACKS Zheng, Y., Zebker, H., Michaelides, R., IEEE IEEE. 2020: 16-19
  • HIGH-PASS FILTERS TO REDUCE THE EFFECTS OF BROAD ATMOSPHERIC CONTRIBUTIONS IN SBAS INVERSIONS: A CASE STUDY IN THE DELAWARE BASIN Pepin, K., Zebker, H. A., Ellsworth, W., IEEE IEEE. 2020: 1030-1033
  • Feasibility of Retrieving Soil Moisture from InSAR Decorrelation Phase and Closure Phase Michaelides, R., Zebker, H., IEEE IEEE. 2020: 12-15
  • AN ANALYTICAL FRAMEWORK FOR UNDERSTANDING PERSISTENT SCATTERER INCIDENCE IN INSAR IMAGERY WITH BANDWIDTH AND WAVELENGTH Huang, S., Zebker, H. A., IEEE IEEE. 2020: 2487-2490
  • THE CASE FOR 6-HOUR REPEAT INSAR Zebker, H. A., Rosen, P. A., IEEE IEEE. 2020: 5949-5952
  • ON THE USE OF PRF DITHERING FOR WIDE SWATH, FINE RESOLUTION INSAR Zebker, H. A., IEEE IEEE. 2020: 9-11
  • JOINT RETRIEVAL OF SOIL MOISTURE AND PERMAFROST ACTIVE LAYER THICKNESS USING L-BAND INSAR AND P-BAND POLSAR Chen, R. H., Michaelides, R. J., Sullivan, T. D., Parsekian, A. D., Zebker, H. A., Moghaddam, M., Schaefer, K. M., IEEE IEEE. 2020: 4606-4609
  • Application of a Range-Doppler Algorithm to Frequency-Domain Beamforming of Ultrasound Signals Jakovljevic, M., Michaelides, R., Biondi, E., Herickhoff, C., Hyun, D., Zebker, H., Dahl, J., IEEE IEEE. 2020
  • An Algorithm for Estimating and Correcting Decorrelation Phase From InSAR Data Using Closure Phase Triplets IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Michaelides, R. J., Zebker, H. A., Zheng, Y. 2019; 57 (12): 10390–97
  • Persistent Scatterer Density by Image Resolution and Terrain Type Huang, S., Zebker, H. A. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2019: 2069–79
  • Titan as Revealed by the Cassini Radar SPACE SCIENCE REVIEWS Lopes, R. C., Wall, S. D., Elachi, C., Birch, S. D., Corlies, P., Coustenis, A., Hayes, A. G., Hofgartner, J. D., Janssen, M. A., Kirk, R. L., LeGall, A., Lorenz, R. D., Lunine, J., Malaskal, M. J., Mastroguiseppe, M., Mitri, G., Neish, C. D., Notarnicolall, C., Paganelli, F., Paillou, P., Poggiali, Radebaugh, J., Rodriguez, S., Schoenfeld, A., Soderblom, J. M., Solomonidou, A., Stofan, E. R., Stiles, B. W., Tosi, F., Turtle, E. P., West, R. D., Wood, C. A., Zebker, H. A., Barnes, J. W., Casarano, D., Encrenaz, P., Farr, T., Grima, C., Hemingway, D., Karatekin, O., Lucas, A., Mitchell, K. L., Ori, G., Orosei, R., Ries, P., Riccio, D., Soderblom, L. A., Zhang, Z. 2019; 215 (4)
  • Frequency domain beamforming of ultrasound signals from inhomogeneous media using range Doppler method The Journal of the Acoustical Society of America Jakovljevic, M., Michaelides, R., Biondi, E., Zebker, H. 2019; 146 (4)

    View details for DOI 10.1121/1.5136930

  • SAR IMAGE STATISTICS BY BANDWIDTH USING A MIXTURE DISTRIBUTION OF PERSISTENT SCATTERER AND CLUTTER DISTRIBUTIONS Huang, S., Zebker, H. A., IEEE IEEE. 2019: 2965–68
  • ANSWERS TO QUESTIONS ABOUT USER-FRIENDLY INSAR DATA PRODUCTS Zebker, H. A., IEEE IEEE. 2019: 354–56
  • Thriving on Our Changing Planet Chapter 10: Earth Surface and Interior: Dynamics and Hazards Thriving on out changing planet Burbank, D., et al 2018

    View details for DOI 10.17226/24938

  • INSAR MISSION-LEVEL PRODUCTS ON DEMAND - DO WE NEED RANGE-DOPPLER? Zebker, H. A., IEEE IEEE. 2018: 68–71
  • PERSISTENT SCATTERER STATISTICS AND THEIR DETECTION Zebker, H. A., Huang, S., IEEE IEEE. 2018: 1356–59
  • Inference of the impact of wildfire on permafrost and active layer thickness in a discontinuous permafrost region using the remotely sensed active layer thickness (ReSALT) algorithm Environmental Research Letters Michaelides, R. J., Schaefer, K., Howard Zebker, Andrew Parsekian, Liu, L., Chen, J., Natali, S. M., Ludwig, S., Schaefer, S. 2018

    View details for DOI 10.1088/1748-9326/aaf932

  • A Singular-Value Decomposition of Closure Phase from InSAR Phase Triplets: Potential for Improved InSAR Time-Series Analysis, and Soil Moisture Time-Series Fall Meeting of the American Geophysical Union Michaelides, R., Zebker, H. 2018
  • The Temporal and Spatial Variability of the Confined Aquifer Head and Storage Properties in the San Luis Valley, Colorado Inferred From Multiple InSAR Missions WATER RESOURCES RESEARCH Chen, J., Knight, R., Zebker, H. A. 2017; 53 (11): 9708–20
  • User-Friendly InSAR Data Products: Fast and Simple Timeseries Processing IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Zebker, H. A. 2017; 14 (11): 2122–26
  • Global drainage patterns and the origins of topographic relief on Earth, Mars, and Titan SCIENCE Black, B. A., Perron, J. T., Hemingway, D., Bailey, E., Nimmo, F., Zebker, H. 2017; 356 (6339): 727-?

    Abstract

    Rivers have eroded the topography of Mars, Titan, and Earth, creating diverse landscapes. However, the dominant processes that generated topography on Titan (and to some extent on early Mars) are not well known. We analyzed drainage patterns on all three bodies and found that large drainages, which record interactions between deformation and erosional modification, conform much better to long-wavelength topography on Titan and Mars than on Earth. We use a numerical landscape evolution model to demonstrate that short-wavelength deformation causes drainage directions to diverge from long-wavelength topography, as observed on Earth. We attribute the observed differences to ancient long-wavelength topography on Mars, recent or ongoing generation of long-wavelength relief on Titan, and the creation of short-wavelength relief by plate tectonics on Earth.

    View details for DOI 10.1126/science.aag0171

    View details for Web of Science ID 000401508400041

    View details for PubMedID 28522528

  • Estimating the permanent loss of groundwater storage in the southern San Joaquin Valley, California WATER RESOURCES RESEARCH Smith, R. G., Knight, R., Chen, J., Reeves, J. A., Zebker, H. A., Farr, T., Liu, Z. 2017; 53 (3): 2133-2148
  • Phase Correction of Single-Look Complex Radar Images for User-Friendly Efficient Interferogram Formation IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Zheng, Y., Zebker, H. 2017; 10 (6)
  • Titan's "Magic Islands": Transient features in a hydrocarbon sea ICARUS Hofgartner, J. D., Hayes, A. G., Lunine, J. I., Zebker, H., Lorenz, R. D., Malaska, M. J., Mastrogiuseppe, M., Notarnicola, C., Soderblom, J. M. 2016; 271: 338-349
  • Constraining the physical properties of Titan's empty lake basins using nadir and off-nadir Cassini RADAR backscatter ICARUS Michaelides, R. J., Hayes, A. G., Mastrogiuseppe, M., Zebker, H. A., Farr, T. G., Malaska, M. J., Poggiali, V., Mullen, J. P. 2016; 270: 57-66
  • Confined aquifer head measurements and storage properties in the San Luis Valley, Colorado, from spaceborne InSAR observations WATER RESOURCES RESEARCH Chen, J., Knight, R., Zebker, H. A., Schreueder, W. A. 2016; 52 (5): 3623-3636
  • Ground-penetrating radar-derived measurements of active-layer thickness on the landscape scale with sparse calibration at Toolik and Happy Valley, Alaska GEOPHYSICS Chen, A., Parsekian, A. D., Schaefer, K., Jafarov, E., Panda, S., Liu, L., Zhang, T., Zebker, H. 2016; 81 (2): H9-H19
  • 4-Dimensional Imaging from Interferometric Synthetic Aperture Radar Zebker, H. A., IEEE IEEE. 2016
  • ROBUST AND EFFICIENT INSAR DEFORMATION TIME SERIES PROCESSING Zebker, H. A., Zheng, Y., IEEE IEEE. 2016: 3198–3200
  • A persistent scatterer interpolation for retrieving accurate ground deformation over InSAR-decorrelated agricultural fields GEOPHYSICAL RESEARCH LETTERS Chen, J., Zebker, H. A., Knight, R. 2015; 42 (21): 9294-9301
  • Remote sensing measurements of thermokarst subsidence using InSAR JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE Liu, L., Schaefer, K. M., Chen, A. C., Gusmeroli, A., Zebker, H. A., Zhang, T. 2015; 120 (9): 1935-1948
  • Remotely Sensed Active Layer Thickness (ReSALT) at Barrow, Alaska Using Interferometric Synthetic Aperture Radar REMOTE SENSING Schaefer, K., Liu, L., Parsekian, A., Jafarov, E., Chen, A., Zhang, T., Gusmeroli, A., Panda, S., Zebker, H. A., Schaefer, T. 2015; 7 (4): 3735-3759

    View details for DOI 10.3390/rs70403735

    View details for Web of Science ID 000354789300016

  • Groundwater extraction, land subsidence, and sea-level rise in the Mekong Delta, Vietnam ENVIRONMENTAL RESEARCH LETTERS Erban, L. E., Gorelick, S. M., Zebker, H. A. 2014; 9 (8)
  • The 2010 slow slip event and secular motion at Kilauea, Hawaii, inferred from TerraSAR-X InSAR data JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH Chen, J., Zebker, H. A., Segall, P., Miklius, A. 2014; 119 (8): 6667-6683
  • An Analysis of the Uncertainty in InSAR Deformation Measurements for Groundwater Applications in Agricultural Areas IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING Reeves, J. A., Knight, R., Zebker, H. A. 2014; 7 (7): 2992-3001
  • Shape, topography, gravity anomalies and tidal deformation of Titan ICARUS Mitri, G., Meriggiola, R., Hayes, A., Lefevre, A., Tobie, G., Genova, A., Lunine, J. I., Zebker, H. 2014; 236: 169-177
  • Transient features in a Titan sea NATURE GEOSCIENCE Hofgartner, J. D., Hayes, A. G., Lunine, J. I., Zebker, H., Stiles, B. W., Sotin, C., Barnes, J. W., Turtle, E. P., Baines, K. H., Brown, R. H., Buratti, B. J., Clark, R. N., Encrenaz, P., KIRK, R. D., Le Gall, A., Lopes, R. M., Lorenz, R. D., Malaska, M. J., Mitchell, K. L., Nicholson, P. D., Paillou, P., Radebaugh, J., Wall, S. D., Wood, C. 2014; 7 (7): 493-496

    View details for DOI 10.1038/NGEO2190

    View details for Web of Science ID 000338832700008

  • InSAR detects increase in surface subsidence caused by an Arctic tundra fire GEOPHYSICAL RESEARCH LETTERS Liu, L., Jafarov, E. E., Schaefer, K. M., Jones, B. M., Zebker, H. A., Williams, C. A., Rogan, J., Zhang, T. 2014; 41 (11): 3906-3913
  • Estimating temporal changes in hydraulic head using InSAR data in the San Luis Valley, Colorado WATER RESOURCES RESEARCH Reeves, J. A., Knight, R., Zebker, H. A., Kitanidis, P. K., Schreueder, W. A. 2014; 50 (5): 4459-4473
  • The bathymetry of a Titan sea GEOPHYSICAL RESEARCH LETTERS Mastrogiuseppe, M., Poggiali, V., Hayes, A., Lorenz, R., Lunine, J., Picardi, G., Seu, R., Flamini, E., Mitri, G., Notarnicola, C., Paillou, P., Zebker, H. 2014; 41 (5): 1432-1437
  • Surface of Ligeia Mare, Titan, from Cassini altimeter and radiometer analysis GEOPHYSICAL RESEARCH LETTERS Zebker, H., Hayes, A., Janssen, M., Le Gall, A., Lorenz, R., Wye, L. 2014; 41 (2): 308-313
  • Reducing Ionospheric Effects in InSAR Data Using Accurate Coregistration IEEE Transactions on Geoscience and Remote Sensing, Chen, A., Zebker, H. 2014; 52 (1): 60-70
  • Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska CRYOSPHERE Liu, L., Schaefer, K., Gusmeroli, A., Grosse, G., Jones, B. M., Zhang, T., Parsekian, A. D., Zebker, H. A. 2014; 8 (3): 815-826
  • Reducing Ionospheric Effects in InSAR Data Using Accurate Coregistration IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Chen, A. C., Zebker, H. A. 2014; 52 (1): 60-70
  • Interferometric SAR in Microwave Radar and Radiometric Remote Sensing Zebker, H., A. edited by Ulaby, F., Long, D. University of Michigan Press. 2014: 1
  • Surface of Ligeia Mare, Titan, from Cassini altimeter and radiometer analysis. Geophysical Research Letters Zebker, H., Hayes, A., Janssen, M., Le Gall, A., Lorenz, R., Wye, L. 2014
  • Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence. Proceedings of the National Academy of Sciences of the United States of America Erban, L. E., Gorelick, S. M., Zebker, H. A., Fendorf, S. 2013; 110 (34): 13751-13756

    Abstract

    Deep aquifers in South and Southeast Asia are increasingly exploited as presumed sources of pathogen- and arsenic-free water, although little is known of the processes that may compromise their long-term viability. We analyze a large area (>1,000 km(2)) of the Mekong Delta, Vietnam, in which arsenic is found pervasively in deep, Pliocene-Miocene-age aquifers, where nearly 900 wells at depths of 200-500 m are contaminated. There, intensive groundwater extraction is causing land subsidence of up to 3 cm/y as measured using satellite-based radar images from 2007 to 2010 and consistent with transient 3D aquifer simulations showing similar subsidence rates and total subsidence of up to 27 cm since 1988. We propose a previously unrecognized mechanism in which deep groundwater extraction is causing interbedded clays to compact and expel water containing dissolved arsenic or arsenic-mobilizing solutes (e.g., dissolved organic carbon and competing ions) to deep aquifers over decades. The implication for the broader Mekong Delta region, and potentially others like it across Asia, is that deep, untreated groundwater will not necessarily remain a safe source of drinking water.

    View details for DOI 10.1073/pnas.1300503110

    View details for PubMedID 23918360

    View details for PubMedCentralID PMC3752228

  • A global topographic map of Titan ICARUS Lorenz, R. D., Stiles, B. W., Aharonson, O., Lucas, A., Hayes, A. G., Kirk, R. L., Zebker, H. A., Turtle, E. P., Neish, C. D., Stofan, E. R., Barnes, J. W. 2013; 225 (1): 367-377
  • Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR The Cryosphere Discuss Liu, L., Millar, C., Westfall, R., Zebker, H. 2013; 7: 343-371

    View details for DOI 10.5194/tcd-7-343-2013

  • CHARACTERIZATION AND IDENTIFICATION OF PARTIALLY CORRELATED PERSISTENT SCATTERERS FOR INSAR REMOTE SENSING IEEE International Geoscience and Remote Sensing Symposium (IGARSS) Lien, J., Zebker, H. IEEE. 2013: 145–148
  • Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence Proceedings of the National Academy of Sciences Erban, L. E., Gorelick, S. M., Zebker, H. A., S, F. 2013: 13751–56

    Abstract

    Deep aquifers in South and Southeast Asia are increasingly exploited as presumed sources of pathogen- and arsenic-free water, although little is known of the processes that may compromise their long-term viability. We analyze a large area (>1,000 km(2)) of the Mekong Delta, Vietnam, in which arsenic is found pervasively in deep, Pliocene-Miocene-age aquifers, where nearly 900 wells at depths of 200-500 m are contaminated. There, intensive groundwater extraction is causing land subsidence of up to 3 cm/y as measured using satellite-based radar images from 2007 to 2010 and consistent with transient 3D aquifer simulations showing similar subsidence rates and total subsidence of up to 27 cm since 1988. We propose a previously unrecognized mechanism in which deep groundwater extraction is causing interbedded clays to compact and expel water containing dissolved arsenic or arsenic-mobilizing solutes (e.g., dissolved organic carbon and competing ions) to deep aquifers over decades. The implication for the broader Mekong Delta region, and potentially others like it across Asia, is that deep, untreated groundwater will not necessarily remain a safe source of drinking water.

    View details for DOI 10.1073/pnas.1300503110

    View details for PubMedCentralID PMC3752228

  • Phased Arrays in Time and Space: A Review 5th IEEE International Symposium on Phased Array Systems and Technology Zebker, H. A. IEEE. 2013: 171–173
  • Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR CRYOSPHERE Liu, L., Millar, C. I., Westfall, R. D., Zebker, H. A. 2013; 7 (4): 1109-1119
  • Reducing Ionospheric Effects in InSAR Data Using Accurate Coregistration IEEE Transactions on Geoscience and Remote Sensing Chen, A., C., Zebker, H., A. 2013; PP (99): 1-11
  • A rigid and weathered ice shell on Titan. Nature Hemingway, D., Nimmo, F., Zebker, H., Iess, L. 2013; 500 (7464): 550-552
  • Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska. Cryosphere Discussions Liu, L., Schaefer, K., Gusmeroli, A., Grosse, G., Jones, B., M., Zhang, T., Zebker, Howard, A. 2013; 7 (6)
  • InSAR Study of Shoreline Change along the Damietta Promontory, Egypt JOURNAL OF COASTAL RESEARCH Aly, M. H., Giardino, J. R., Klein, A. G., Zebker, H. A. 2012; 28 (5): 1263-1269
  • Ionospheric Artifacts in Simultaneous L-Band InSAR and GPS Observations IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Chen, J., Zebker, H. A. 2012; 50 (4): 1227-1239
  • Land subsidence in the Nile Delta of Egypt observed by persistent scatterer interferometry REMOTE SENSING LETTERS Aly, M. H., Klein, A. G., Zebker, H. A., Giardino, J. R. 2012; 3 (7): 621-630
  • Earth Crustal Deformation from Space Using InSAR Zebker, H., A. 2012
  • Land subsidence in the Nile Delta of Egypt observed by persistent scatterer interferometry Remote Sensing Letters, Aly, M. H., Klein, A. G., Zebker, H. A., Giardino, J. R. 2012; 3
  • An analysis of the uncertainty in InSAR deformation measurements for groundwater applications IEEE Transactions on Geoscience and Remote Sensing Reeves, J. A., Knight, R., Zebker, H. A. 2012
  • High quality InSAR data linked to seasonal change in hydraulic head for an agricultural area in the San Luis Valley, Colorado WATER RESOURCES RESEARCH Reeves, J. A., Knight, R., Zebker, H. A., Schreueder, W. A., Agram, P. S., Lauknes, T. R. 2011; 47
  • InSAR detection of residual settlement of an ocean reclamation engineering project: a case study of Hong Kong International Airport JOURNAL OF OCEANOGRAPHY Zhao, Q., Lin, H., Gao, W., Zebker, H. A., Chen, A., Yeung, K. 2011; 67 (4): 415-426
  • Comparison of Persistent Scatterers and Small Baseline Time-Series InSAR Results: A Case Study of the San Francisco Bay Area IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Shanker, P., Casu, F., Zebker, H. A., Lanari, R. 2011; 8 (4): 592-596
  • Cassini SAR, radiometry, scatterometry and altimetry observations of Titan's dune fields ICARUS Le Gall, A., Janssen, M. A., Wye, L. C., Hayes, A. G., Radebaugh, J., Savage, C., Zebker, H., Lorenz, R. D., Lunine, J. I., Kirk, R. L., Lopes, R. M., Wall, S., Callahan, P., Stofan, E. R., Farr, T. 2011; 213 (2): 608-624
  • Smoothing Criteria for Regularized Matrix Inversion of Bistatic Radar Echoes PROCEEDINGS OF THE IEEE Gunnarsdottir, H. M., Linscott, I. R., Zebker, H. 2011; 99 (5): 895-905
  • InSAR Deformation Time Series Using an L-1-Norm Small-Baseline Approach IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Lauknes, T. R., Zebker, H. A., Larsen, Y. 2011; 49 (1): 536-546
  • TECHNIQUES AND TOOLS FOR ESTIMATING IONOSPHERIC EFFECTS IN INTERFEROMETRIC AND POLARIMETRIC SAR DATA IEEE International Geoscience and Remote Sensing Symposium (IGARSS) Rosen, P., Lavalle, M., Pi, X., Buckley, S., SZELIGA, W., Zebker, H., Gurrola, E. IEEE. 2011: 1501–1504
  • Ionospheric Artifacts in Simultaneous L-Band InSAR and GPS Observations IEEE Transactions on Geoscience and Remote Sensing Chen, J., Zebker, H., A. 2011; PP (99): 1 – 13
  • Comparison of Persistent Scatterers and Small Baseline Time-Series InSAR Results: A Case Study of the San Francisco Bay Area, IEEE Geoscience and Remote Sensing Letters Shanker, P., Casu, F., Zebker, H. A., Lanari, R. 2011; 8: 592-596
  • Airborne Radar Interferometric Repeat-Pass Processing, NASA Tech Briefs Hensley, S., Michel, TR., Jones, CE., Muellerschoen, RJ., Chapman, BD., Fore, A., Simard, M., Zebker, HA. 2011; 35: 28-30
  • InSAR detection of residual settlement of an ocean reclamation engineering project: a case study of Hong Kong International Airport, J. Oceanography Zhao, Q., Lin, H., Gao, W., Zebker, H. A., Chen, A., Yeung, K. 2011; 67: 415-426
  • Bathymetry and absorptivity of Titan's Ontario Lacus, Journal Of Geophysical Research Hayes, A. G., Wolf, A. S., Aharonson, O., Zebker, H., Lorenz, R., Kirk, R. L., Paillou, P., Lunine, J., Wye, L., Callahan, P., Wall, S., Elachi, C. 2011; 115: 11

    View details for DOI 10.1029/2009je003557

  • Ionospheric Artifacts in Simultaneous L-Band InSAR and GPS Observations, IEEE Transactions on Geoscience and Remote Sensing, Chen, J., Zebker, H. A. 2011; PP: 1-13
  • High quality InSAR data linked to seasonal change in hydraulic head for an agricultural area in the San Luis Valley, Colorado, Water Resources Research Reeves, J. A., Knight, R., Zebker, H. A., Schreuder, W. A., Agram, P. S., Lauknes, T. R. 2011; 47: 11
  • Regional geomorphology and history of Titan’s Xanadu province Icarus Radebaugh, J., Lorenz, R.D., Wall, S.D., Kirk, R.L., Wood, C.A., Lunine, J.I., Stofan, E.R., Lopes, R.M.C., Valora, P., Farr, T.G., Hayes, A.G., Stiles, B., Mitri, G., Zebker, H., Janssen, M., Wye, L., Gall, A. Le, Mitchell, K.L., Paganelli, F., West, R.D., Schaller, E.L. 2011; 211: 672-685
  • Detailed landslide mapping in northern Norway with small-baseline and persistent scatterer interferometric SAR time-series methods Remote Sens. Environ. Lauknes, T. R., Shanker, P., Dehls, J., Zebker, H., Henderson, I., Larsen, Y. 2011; 114: 2097-2109
  • Transient surface liquid in Titan's polar regions from Cassini ICARUS Hayes, A. G., Aharonson, O., Lunine, J. I., Kirk, R. L., Zebker, H. A., Wye, L. C., Lorenz, R. D., Turtle, E. P., Paillou, P., Mitri, G., Wall, S. D., Stofan, E. R., Mitchell, K. L., Elachi, C. 2011; 211 (1): 655-671
  • Regional geomorphology and history of Titan's Xanadu province ICARUS Radebaugh, J., Lorenz, R. D., Wall, S. D., Kirk, R. L., Wood, C. A., Lunine, J. I., Stofan, E. R., Lopes, R. M., Valora, P., Farr, T. G., Hayes, A., Stiles, B., Mitri, G., Zebker, H., Janssen, M., Wye, L., LEGALL, A., Mitchell, K. L., Paganelli, F., West, R. D., Schaller, E. L. 2011; 211 (1): 672-685
  • Geodetically Accurate InSAR Data Processor IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Zebker, H. A., Hensley, S., Shanker, P., Wortham, C. 2010; 48 (12): 4309-4321
  • Bathymetry and absorptivity of Titan's Ontario Lacus JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS Hayes, A. G., Wolf, A. S., Aharonson, O., Zebker, H., Lorenz, R., Kirk, R. L., Paillou, P., Lunine, J., Wye, L., Callahan, P., Wall, S., Elachi, C. 2010; 115
  • Detailed rockslide mapping in northern Norway with small baseline and persistent scatterer interferometric SAR time series methods REMOTE SENSING OF ENVIRONMENT Lauknes, T. R., Shanker, A. P., Dehls, J. F., Zebker, H. A., Henderson, I. H., Larsen, Y. 2010; 114 (9): 2097-2109
  • Geodetic evidence for en echelon dike emplacement and concurrent slow slip during the June 2007 intrusion and eruption at Kilauea volcano, Hawaii JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH Montgomery-Brown, E. K., Sinnett, D. K., Poland, M., Segall, P., Orr, T., Zebker, H., Miklius, A. 2010; 115
  • New Cassini RADAR results for Saturn's icy satellites International Conference on Saturn from Cassini-Huygens Ostro, S. J., West, R. D., Wye, L. C., Zebker, H. A., Janssen, M. A., Stiles, B., Kelleher, K., Anderson, Y. Z., Boehmer, R. A., Callahan, P., Gim, Y., Hamilton, G. A., Johnson, W. T., Veeramachaneni, C., Lorenz, R. D. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2010: 498–506
  • Active shoreline of Ontario Lacus, Titan: A morphological study of the lake and its surroundings GEOPHYSICAL RESEARCH LETTERS Wall, S., Hayes, A., Bristow, C., Lorenz, R., Stofan, E., Lunine, J., Le Gall, A., Janssen, M., Lopes, R., Wye, L., Soderblom, L., Paillou, P., Aharonson, O., Zebker, H., Farr, T., Mitri, G., Kirk, R., Mitchell, K., Notarnicola, C., Casarano, D., Ventura, B. 2010; 37
  • Edgelist phase unwrapping algorithm for time series InSAR analysis JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION Shanker, A. P., Zebker, H. 2010; 27 (3): 605-612

    Abstract

    We present here a new integer programming formulation for phase unwrapping of multidimensional data. Phase unwrapping is a key problem in many coherent imaging systems, including time series synthetic aperture radar interferometry (InSAR), with two spatial and one temporal data dimensions. The minimum cost flow (MCF) [IEEE Trans. Geosci. Remote Sens. 36, 813 (1998)] phase unwrapping algorithm describes a global cost minimization problem involving flow between phase residues computed over closed loops. Here we replace closed loops by reliable edges as the basic construct, thus leading to the name "edgelist." Our algorithm has several advantages over current methods-it simplifies the representation of multidimensional phase unwrapping, it incorporates data from external sources, such as GPS, where available to better constrain the unwrapped solution, and it treats regularly sampled or sparsely sampled data alike. It thus is particularly applicable to time series InSAR, where data are often irregularly spaced in time and individual interferograms can be corrupted with large decorrelated regions. We show that, similar to the MCF network problem, the edgelist formulation also exhibits total unimodularity, which enables us to solve the integer program problem by using efficient linear programming tools. We apply our method to a persistent scatterer-InSAR data set from the creeping section of the Central San Andreas Fault and find that the average creep rate of 22 mm/Yr is constant within 3 mm/Yr over 1992-2004 but varies systematically with ground location, with a slightly higher rate in 1992-1998 than in 1999-2003.

    View details for Web of Science ID 000275239600031

    View details for PubMedID 20208954

  • InSAR Deformation Time Series Using an L_1 -Norm Small-Baseline Approach Geoscience and Remote Sensing, IEEE Transactions Lauknes, T. R., Zebker, H. A., Larsen, Y. 2010; PP
  • Bathymetry and absorptivity of Titan's Ontario Lacus Journal Of Geophysical Research Hayes, A., G., Wolf, A., S., Aharonson, O., Zebker, H., Lorenz, R., Kirk, R., L. 2010; 115: E09009, 11

    View details for DOI 10.1029/2009je003557

  • Permanent Scatterer investigation of land subsidence in Greater Cairo, Egypt GEOPHYSICAL JOURNAL INTERNATIONAL Aly, M. H., Zebker, H. A., Giardino, J. R., Klein, A. G. 2009; 178 (3): 1238-1245
  • Smoothness of Titan's Ontario Lacus: Constraints from Cassini RADAR specular reflection data GEOPHYSICAL RESEARCH LETTERS Wye, L. C., Zebker, H. A., Lorenz, R. D. 2009; 36
  • Determining Titan surface topography from Cassini SAR data ICARUS Stiles, B. W., Hensley, S., Gim, Y., Bates, D. M., Kirk, R. L., Hayes, A., Radebaugh, J., Lorenz, R. D., Mitchell, K. L., Callahan, P. S., Zebker, H., Johnson, W. T., Wall, S. D., Lunine, J. I., Wood, C. A., Janssen, M., Pelletier, F., West, R. D., Veeramacheneni, C. 2009; 202 (2): 584-598
  • Sparse Two-Dimensional Phase Unwrapping Using Regular Grid Methods IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Shanker, A. P., Zebker, H. A. 2009; 6 (3): 519-522
  • Cassini RADAR Sequence Planning and Instrument Performance IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING West, R. D., Anderson, Y., Boehmer, R., Borgarelli, L., Callahan, P., Elachi, C., Gim, Y., Hamilton, G., Hensley, S., Janssen, M. A., Johnson, W. T., Kelleher, K., Lorenz, R., Ostro, S., Roth, L., Shaffer, S., Stiles, B., Wall, S., Wye, L. C., Zebker, H. A. 2009; 47 (6): 1777-1795
  • Size and Shape of Saturn's Moon Titan SCIENCE Zebker, H. A., Stiles, B., Hensley, S., Lorenz, R., Kirk, R. L., Lunine, J. 2009; 324 (5929): 921-923

    Abstract

    Cassini observations show that Saturn's moon Titan is slightly oblate. A fourth-order spherical harmonic expansion yields north polar, south polar, and mean equatorial radii of 2574.32 +/- 0.05 kilometers (km), 2574.36 +/- 0.03 km, and 2574.91 +/- 0.11 km, respectively; its mean radius is 2574.73 +/- 0.09 km. Titan's shape approximates a hydrostatic, synchronously rotating triaxial ellipsoid but is best fit by such a body orbiting closer to Saturn than Titan presently does. Titan's lack of high relief implies that most--but not all--of the surface features observed with the Cassini imaging subsystem and synthetic aperture radar are uncorrelated with topography and elevation. Titan's depressed polar radii suggest that a constant geopotential hydrocarbon table could explain the confinement of the hydrocarbon lakes to high latitudes.

    View details for DOI 10.1126/science.1168905

    View details for Web of Science ID 000266048800033

    View details for PubMedID 19342551

  • Sparse Two-Dimensional Phase Unwrapping Using Regular-Grid Methods IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Agram, P. S., Zebker, H. A. 2009; 6 (2): 327-331
  • Analysis and interpretation of Cassini Titan radar altimeter echoes ICARUS Zebker, H. A., Gim, Y., Callahan, P., Hensley, S., Lorenz, R. 2009; 200 (1): 240-255
  • The Shape of Saturn's Moon Titan From Cassini Radar Altimeter And SAR Monopulse Observations 2009 IEEE Radar Conference Zebker, H. A., Hensley, S., Stiles, B., Callahan, P., Gim, Y., Lorenz, R. IEEE. 2009: 175–177
  • RESIDUAL MOTION ESTIMATION FOR UAVSAR: IMPLICATIONS of an ELECTRONICALLY SCANNED ARRAY 2009 IEEE Radar Conference Hensley, S., Michel, T., Simard, M., Jones, C., Muellerschoen, R., Le, C., Zebker, H., Chapman, B. IEEE. 2009: 450–454
  • Titan's diverse landscapes as evidenced by Cassini RADAR's third and fourth looks at Titan ICARUS Lunine, J. I., Elachi, C., Wall, S. D., Janssen, M. A., Allison, M. D., Anderson, Y., Boehmer, R., Callahan, P., Encrenaz, P., Flamini, E., Franceschetti, G., Gim, Y., Hamilton, G., Hensley, S., Johnson, W. T., Kelleher, K., Kirk, R. L., Lopes, R. M., Lorenz, R., Muhleman, D. O., Orosei, R., Ostro, S. J., Paganelli, F., Paillou, P., Picardi, G., Posa, F., Radebaugh, J., Roth, L. E., Seu, R., Shaffer, S., Soderblom, L. A., Stiles, B., Stofan, E. R., Vetrella, S., West, R., Wood, C. A., Wye, L., Zebker, H., Alberti, G., Karkoschka, E., Rizk, B., McFarlane, E., See, C., Kazeminejad, B. 2008; 195 (1): 415-433
  • Titan's surface from reconciled Cassini microwave reflectivity and emissivity observations ICARUS Zebker, H. A., Wye, L. C., Janssen, M. A. 2008; 194 (2): 704-710
  • Titan's inventory of organic surface materials GEOPHYSICAL RESEARCH LETTERS Lorenz, R. D., Mitchell, K. L., Kirk, R. L., Hayes, A. G., Aharonson, O., Zebker, H. A., Paillou, P., Radebaugh, J., Lunine, J. I., Janssen, M. A., Wall, S. D., Lopes, R. M., Stiles, B., Ostro, S., Mitri, G., Stofan, E. R. 2008; 35 (2)
  • Radar and Lidar Measurement of Terrestrial Processes Eos Donnellan, A., Zebker, H., Ranson, K. J. 2008; 89: 349-50
  • Deformation, Ecosystem Structure, and Dynamics of Ice (DESDynI) 2008 IEEE Aerospace Conference Donnellan, A., Rosen, P., Graf, J., Loverro, A., Freeman, A., Treuhaft, R., Oberto, R., Simard, M., Rignot, E., Kwok, R., Pi, X., Blair, J. B., Abdalati, W., Ranson, J., Zebker, H., Hager, B., Shugart, H., Fahnestock, M., Dubayah, R. IEEE. 2008: 163–175
  • Titan’s Inventory of Organic Surface Materials Geophysical Research Letters Lorenz, R., D., Mitchell, K., L., Kirk, R., L., Hayes, A., G., Zebker, H., A., Paillou, P. 2008; 35: L02206

    View details for DOI 10.1029/2007GL032118

  • Radar and Radar and Lidar Measurement of Terrestrial Processes, EOS Transactions American Geophysical Union Donnellan, A., Zebker, H., Ranson, K., J. 2008; 89 (38)

    View details for DOI 10.1029/2008EO380002

  • Report of the NASA InSAR Processing Workshop edited by Zebker, H., A. 2008
  • THE UAVSAR INSTRUMENT: DESCRIPTION AND FIRST RESULTS 2008 IEEE Radar Conference Hensley, S., Wheeler, K., Sadowy, G., Jones, C., Shaffer, S., Zebker, H., Miller, T., Heavey, B., Chuang, E., Chao, R., Vines, K., Nishimoto, K., Prater, J., Carrico, B., Chamberlain, N., Shimada, J., Simard, M., Chapman, B., Muellerschoen, R., Le, C., Michel, T., Hamilton, G., Robison, D., Neumann, G., Meyer, R., Smith, P., Granger, J., Rosen, P., Flower, D., Smith, R. IEEE. 2008: 827–832
  • Persistent scatterer selection using maximum likelihood estimation GEOPHYSICAL RESEARCH LETTERS Shanker, P., Zebker, H. 2007; 34 (22)
  • ScanSAR-to-Stripmap mode interferometry processing using ENVISAT/ASAR data 6th European Conference on Synthetic Aperture Radar Ortiz, A. B., Zebker, H. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2007: 3468–80
  • UAVSAR: New NASA airborne SAR system for research IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE Rosen, P. A., Hensley, S., Wheeler, K., Sadowy, G., Miller, T., Shaffer, S., Muellerschoen, R., Jones, C., Madsen, S., Zebker, H. 2007; 22 (11): 21-28
  • Phase unwrapping in three dimensions with application to InSAR time series JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION Hooper, A., Zebker, H. A. 2007; 24 (9): 2737-2747

    Abstract

    The problem of phase unwrapping in two dimensions has been studied extensively in the past two decades, but the three-dimensional (3D) problem has so far received relatively little attention. We develop here a theoretical framework for 3D phase unwrapping and also describe two algorithms for implementation, both of which can be applied to synthetic aperture radar interferometry (InSAR) time series. We test the algorithms on simulated data and find both give more accurate results than a two-dimensional algorithm. When applied to actual InSAR time series, we find good agreement both between the algorithms and with ground truth.

    View details for Web of Science ID 000249813000026

    View details for PubMedID 17767243

  • Persistent scatterer interferometric synthetic aperture radar for crustal deformation analysis, with application to Volcan Alcedo, Galapagos JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH Hooper, A., Segall, P., Zebker, H. 2007; 112 (B7)
  • Interferogram formation in the presence of complex and large deformation GEOPHYSICAL RESEARCH LETTERS Yun, S., Zebker, H., Segall, P., Hooper, A., Poland, M. 2007; 34 (12)
  • Electrical properties of Titan's surface from Cassini RADAR scatterometer measurements ICARUS Wye, L. C., Zebker, H. A., Ostro, S. J., West, R. D., Gim, Y., Lorenz, R. D. 2007; 188 (2): 367-385
  • Titan's young surface: Initial impact crater survey by Cassini RADAR and model comparison GEOPHYSICAL RESEARCH LETTERS Lorenz, R. D., Wood, C. A., Lunine, J. I., Wall, S. D., Lopes, R. M., Mitchell, K. L., Paganelli, F., Anderson, Y. Z., Wye, L., Tsai, C., Zebker, H., Stofan, E. R. 2007; 34 (7)
  • Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper ICARUS Lopes, R. M., Mitchell, K. L., Stofan, E. R., Lunine, J. I., Lorenz, R., Paganelli, F., Kirk, R. L., Wood, C. A., Wall, S. D., Robshaw, L. E., Fortes, A. D., Neish, C. D., Radebaugh, J., Reffet, E., Ostro, S. J., Elachi, C., Allison, M. D., Anderson, Y., Boehmer, R., Boubin, G., Callahan, P., Encrenaz, P., Flamini, E., Francescetti, G., Gim, Y., Hamilton, G., Hensley, S., Janssen, M. A., Johnson, W. T., Kelleher, K., Muhleman, D. O., Ori, G., Orosei, R., Picardi, G., Posa, F., Roth, L. E., Seu, R., Shaffer, S., Soderblom, L. A., Stiles, B., Vetrella, S., West, R. D., Wye, L., Zebker, H. A. 2007; 186 (2): 395-412
  • The lakes of Titan NATURE Stofan, E. R., Elachi, C., Lunine, J. I., Lorenz, R. D., Stiles, B., Mitchell, K. L., Ostro, S., Soderblom, L., Wood, C., Zebker, H., Wall, S., Janssen, M., Kirk, R., Lopes, R., Paganelli, F., Radebaugh, J., Wye, L., Anderson, Y., Allison, M., Boehmer, R., Callahan, P., Encrenaz, P., Flamini, E., Francescetti, G., Gim, Y., Hamilton, G., Hensley, S., Johnson, W. T., Kelleher, K., Muhleman, D., Paillou, P., Picardi, G., Posa, F., Roth, L., Seu, R., Shaffer, S., Vetrella, S., West, R. 2007; 445 (7123): 61-64

    Abstract

    The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70 degrees north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table.

    View details for DOI 10.1038/nature05438

    View details for Web of Science ID 000243225100035

    View details for PubMedID 17203056

  • Estimating snow accumulation from InSAR correlation observations IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Oveisgharan, S., Zebker, H. A. 2007; 45 (1): 10-20
  • Florida Workshop to Assess the National Research Council Decadal Survey Recommendation for the DESDynI Radar/Lidar Space Mission DESDynI Writing Committee, National Aeronautics and Space Administration edited by Zebker, H., A. Earth Science Division. 2007: 1
  • Titan’s young surface: Initial impact crater survey by Cassini RADAR and model comparison Geophysical Research Letters Lorenz, R., D., Wood, C., A., Lunine, J., I., Wall, S., D., Lopes, R., M., Mitchell, K., L., Zebker, Howard, A. 2007; 34: L07204
  • The Lakes and Seas of Titan Eos Lopes, R. M. C., Mitchell, K. L., Wall, S. D., Mitri, G., Janssen, M., Ostro, S., Kirk, R. L., Hayes, A. G., Stofan, E. R., Lunine, J. I., Lorenz, R. D., Wood, C., Radebaugh, J., Paillou, P., Zebker, H., Paganelli, And F. 2007; 88: 569-576
  • Mapping of Titan: Results from the first Titan radar passes ICARUS Stofan, E. R., Lunine, J. I., Lopes, R., Paganelli, F., Lorenz, R. D., Wood, C. A., Kirk, R., Wall, S., Elachi, C., Soderblom, L. A., Ostro, S., Janssen, M., Radebaugh, J., Wye, L., Zebker, H., Anderson, Y., Allison, M., Boehmer, R., Callahan, P., Encrenaz, P., Flamini, E., Francescetti, G., Girn, Y., Hamilton, G., Hensley, S., Johnson, W. T., Kelleher, K., Muhleman, D., Picardi, G., Posa, F., Roth, L., Seu, R., Shaffer, S., Stiles, B., Vetrella, S., West, R. 2006; 185 (2): 443-456
  • Correction for interferometric synthetic aperture radar atmospheric phase artifacts using time series of zenith wet delay observations from a GPS network JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH Onn, F., Zebker, H. A. 2006; 111 (B9)
  • Measuring two-dimensional movements using a single InSAR pair GEOPHYSICAL RESEARCH LETTERS Bechor, N. B., Zebker, H. A. 2006; 33 (16)
  • Cassini RADAR observations of Enceladus, Tethys, Dione, Rhea, Iapetus, Hyperion, and Phoebe ICARUS Ostro, S. J., West, R. D., Janssen, M. A., Lorenz, R. D., Zebker, H. A., Black, G. J., Lunine, J. I., Wye, L. C., Lopes, R. M., Wall, S. D., Elachi, C., Roth, L., Hensley, S., Kelleher, K., Hamilton, G. A., Gim, Y., Anderson, Y. Z., Boehmer, R. A., Johnson, W. T. 2006; 183 (2): 479-490
  • Titan Radar Mapper observations from Cassini's T3 fly-by NATURE Elachi, C., Wall, S., Janssen, M., Stofan, E., Lopes, R., Kirk, R., Lorenz, R., Lunine, J., Paganelli, F., Soderblom, L., Wood, C., Wye, L., Zebker, H., Anderson, Y., Ostro, S., Allison, M., Boehmer, R., Callahan, P., Encrenaz, P., Flamini, E., Francescetti, G., Gim, Y., Hamilton, G., Hensley, S., Johnson, W., Kelleher, K., Muhleman, D., Picardi, G., Posa, F., Roth, L., Seu, R., Shaffer, S., Stiles, B., Vetrella, S., West, R. 2006; 441 (7094): 709-713

    Abstract

    Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity.

    View details for DOI 10.1038/nature04786

    View details for Web of Science ID 000238095100044

    View details for PubMedID 16760968

  • The sand seas of Titan: Cassini RADAR observations of longitudinal dunes SCIENCE Lorenz, R. D., Wall, S., Radebaugh, J., Boubin, G., Reffet, E., Janssen, M., Stofan, E., Lopes, R., Kirk, R., Elachi, C., Lunine, J., Mitchell, K., Paganelli, F., Soderblom, L., Wood, C., Wye, L., Zebker, H., Anderson, Y., Ostro, S., Allison, M., Boehmer, R., Callahan, P., Encrenaz, P., Ori, G. G., Francescetti, G., Gim, Y., Hamilton, G., Hensley, S., Johnson, W., Kelleher, K., Muhleman, D., Picardi, G., Posa, F., Roth, L., Seu, R., Shaffer, S., Stiles, B., Vetrella, S., Flamini, E., West, R. 2006; 312 (5774): 724-727

    Abstract

    The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show approximately 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of approximately 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.

    View details for DOI 10.1126/science.1123257

    View details for Web of Science ID 000237312100044

    View details for PubMedID 16675695

  • Constraints on magma chamber geometry at Sierra Negra Volcano, Galapagos Islands, based on InSAR observations JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH Yun, S., Segall, P., Zebker, H. 2006; 150 (1-3): 232-243
  • UAVSAR: A new NASA airborne SAR system for science and technology research 2006 IEEE Radar Conference Rosen, P. A., Hensley, S., Wheeler, K., Sadowy, G., Miller, T., Shaffer, S., Muellerschoen, R., Jones, C., Zebker, H., Madsen, S. IEEE. 2006: 22–29
  • Chapter 9: Use of a prediction-error filter in merging high- and low-resolution images Signal and Image Processing for Remote Sensing Yun, S., Zebker, H. CRC Press, Boca Raton, FL, USA. 2006
  • Along track differential InSAR; a new look at the 1999, Hector Mine earthquake Seismological Research Letters Bechor Ben Dov, N., Zebker, H.A. 2006; 77: 315
  • On merging high- and low-resolution DEMs from TOPSAR and SRTM using a prediction-error filter IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Yun, S. H., Ji, J., Zebker, H., Segall, P. 2005; 43 (7): 1682-1690
  • On trapdoor faulting at Sierra Negra volcano, Galapagos JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH Jonsson, S., Zebker, H., Amelung, F. 2005; 144 (1-4): 59-71
  • Cassini radar views the surface of Titan SCIENCE Elachi, C., Wall, S., Allison, M., Anderson, Y., Boehmer, R., Callahan, P., Encrenaz, P., Flamini, E., Franceschetti, G., Gim, Y., Hamilton, G., Hensley, S., Janssen, M., Johnson, W., Kelleher, K., Kirk, R., Lopes, R., Lorenz, R., Lunine, J., Muhleman, D., Ostro, S., Paganelli, F., Picardi, G., Posa, F., Roth, L., Seu, R., Shaffer, S., Soderblom, L., Stiles, B., Stofan, E., Vetrella, S., West, R., Wood, C., Wye, L., Zebker, H. 2005; 308 (5724): 970-974

    Abstract

    The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of approximately 0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.

    View details for DOI 10.1126/science.1109919

    View details for Web of Science ID 000229190700031

    View details for PubMedID 15890871

  • Accurate estimation of correlation in InSAR observations IEEE GEOSCIENCE AND REMOTE SENSING LETTERS Zebker, H. A., Chen, K. 2005; 2 (2): 124-127
  • Status of a UAVSAR designed for repeat pass interferometry for deformation measurements IEEE MTT-S International Microwave Symposium Hensley, S., Wheeler, K., Sadowy, G., Miller, T., Shaffer, S., Muellerschoen, R., Jones, C., Zebker, H., Madsen, S., Rosen, P. IEEE. 2005: 1453–1456
  • InSAR Workshop Summary Report NASA/JPL Document JPL 400-1240, Jet Propulsion Laboratory edited by Zebker, H. California Institute of Technology, Pasadena, CA. 2005: 1
  • Use of a Prediction-error Filter in Merging High- and Low-resolution Images in Signal and Image Processing for Remote Sensing Yun, S., Zebker, H., A. CRC Press. 2005: 1
  • On Merging High and Low Resolution DEMs from TOPSAR and SRTM Using a Prediction-Error Filter IEEE Transactions on Geosci. Rem. Sensing Yun, S., Ji., J., Zebker, H. A., Segall, P. 2005; 43: 1682-1690
  • Community InSAR Workshop Calls for Robust Program and Dedicated Satellite Mission EOS Transactions of the AGU Donnellan, A., Glasscoe, M., Zebker, H. A 2005; 86
  • A new method for measuring deformation on volcanoes and other natural terrains using InSAR persistent scatterers GEOPHYSICAL RESEARCH LETTERS Hooper, A., Zebker, H., Segall, P., Kampes, B. 2004; 31 (23)
  • Radar: The Cassini Titan RADAR Mapper SPACE SCIENCE REVIEWS Elachi, C., Allison, M. D., Borgarelli, L., Encrenaz, P., Im, E., Janssen, M. A., Johnson, W. T., Kirk, R. L., Lorenz, R. D., Lunine, J. I., Muhleman, D. O., Ostro, S. J., Picardi, G., Posa, F., Rapley, C. G., Roth, L. E., Seu, R., Soderblom, L. A., Vetrella, S., Wall, S. D., Wood, C. A., Zebker, H. A. 2004; 115 (1-4): 71-110
  • Spatially-resolved uplift rate of the Mount Sedom (Dead Sea) salt diapir from InSAR observations Israel Journal of Earth Sciences Peíeri, S., Zebker, H. A., Ben-Avraham, Z., Frumkin, A., Hall, J. K. 2004; 53: 99-106
  • A New Method for Measuring Deformation on Volcanoes and Other Natural Terrains Using InSAR Persistent Scatterers Geophysical Research Letters Hooper, A., Zebker, H. A., Segall, P., Kampes, B. 2004; 31: L23611
  • Prospecting for horizontal surface displacements in Antelope Valley, California, using satellite radar interferometry JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE Hoffmann, J., Zebker, H. A. 2003; 108 (F1)
  • Radar stereo- and interferometry-derived digital elevation models: comparison and combination using Radarsat and ERS-2 imagery INTERNATIONAL JOURNAL OF REMOTE SENSING Gelautz, M., Paillou, P., Chen, C. W., Zebker, H. A. 2003; 24 (24): 5243-5264
  • Inverse modeling of interbed storage parameters using land subsidence observations, Antelope Valley, California WATER RESOURCES RESEARCH Hoffmann, J., Galloway, D. L., Zebker, H. A. 2003; 39 (2)
  • Inverse modeling of interbed storage parameters using land subsidence observations, Antelope Valley, California Water Resources Research Hoffmann, J., Galloway, Devin L., Zebker, Howard A. 2003; 39: 1031
  • Phase unwrapping for large SAR interferograms: Statistical segmentation and generalized network models IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Chen, C. W., Zebker, H. A. 2002; 40 (8): 1709-1719
  • Fault slip distribution of the 1999 M-w 7.1 Hector Mine, California, earthquake, estimated from satellite radar and GPS measurements BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA Jonsson, S., Zebker, H., Segall, P., Amelung, F. 2002; 92 (4): 1377-1389
  • Fault slip distribution of the 1999 M (sub w) 7.1 Hector Mine, California, earthquake, estimated from satellite radar and GPS measurements, in Hector Mine, California, earthquake of 16 October 1999 Bulletin of the Seismological Society of America Jonsson, S., Segall, H., Falk;, P. 2002; 7: 1377-1389
  • Phase unwrapping for large SAR interferograms: statistical segmentation and generalized network models, IEEE Transactions on Geoscience and Remote Sensing Chen, C. W.; Zebker, H.A. 2002; 40: 1709-19
  • Inverse modeling of interbed storage parameters using land subsidence observations, Antelope Valley, California, Water Resources Research Hoffmann, J., Galloway, D. L., Zebker, H. A. 2002
  • Seasonal subsidence and rebound in Las Vegas Valley, Nevada, observed by synthetic aperture radar interferometry WATER RESOURCES RESEARCH Hoffmann, J., Zebker, H. A., Galloway, D. L., Amelung, F. 2001; 37 (6): 1551-1566
  • Network approaches to two-dimensional phase unwrapping: intractability and two new algorithms (vol 17, pg 401, 2000) JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION Chen, C. W., Zebker, H. A. 2001; 18 (5): 1192-1192
  • Two-dimensional phase unwrapping with use of statistical models for cost functions in nonlinear optimization JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION Chen, C. W., Zebker, H. A. 2001; 18 (2): 338-351

    Abstract

    Interferometric radar techniques often necessitate two-dimensional (2-D) phase unwrapping, defined here as the estimation of unambiguous phase data from a 2-D array known only modulo 2pi rad. We develop a maximum a posteriori probability (MAP) estimation approach for this problem, and we derive an algorithm that approximately maximizes the conditional probability of its phase-unwrapped solution given observable quantities such as wrapped phase, image intensity, and interferogram coherence. Examining topographic and differential interferometry separately, we derive simple, working models for the joint statistics of the estimated and the observed signals. We use generalized, nonlinear cost functions to reflect these probability relationships, and we employ nonlinear network-flow techniques to approximate MAP solutions. We apply our algorithm both to a topographic interferogram exhibiting rough terrain and layover and to a differential interferogram measuring the deformation from a large earthquake. The MAP solutions are complete and are more accurate than those of other tested algorithms.

    View details for Web of Science ID 000166633400012

    View details for PubMedID 11205980

  • Two -dimensional phase unwrapping with use of statistical models for cost functions in nonlinear optimization Journal of the Optical Society of America A (Optics, Image Science and Vision) Chen, C. W.; Zebker, H.A. 2001; 18: 338-51
  • Penetration depths inferred from interferometric volume decorrelation observed over the Greenland ice sheet IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Hoen, E. W., Zebker, H. A. 2000; 38 (6): 2571-2583
  • Widespread uplift and 'trapdoor' faulting on Galapagos volcanoes observed with radar interferometry NATURE Amelung, F., Jonsson, S., Zebker, H., Segall, P. 2000; 407 (6807): 993-996

    Abstract

    Volcanic uplift, caused by the accumulation of magma in subsurface reservoirs, is a common precursor to eruptions. But, for some volcanoes, uplift of metres or more has not yet led to an eruption. Here we present displacement maps of volcanoes in the Galápagos Islands, constructed using satellite radar interferometry, that might help explain this dichotomy. We show that all but one of the seven volcanoes on the islands of Isabela and Fernandina deformed during 1992-99. Cerro Azul and Fernandina erupted during the observation period and show evidence of inflation, co-eruptive deflation and shallow dyke intrusion. In contrast, the largest volcano, Sierra Negra, has not erupted, yet exhibits spatially and temporally variable deformation, with a maximum uplift of 2.7 m between 1992 and 1999, which can be modelled by a shallow inflating sill. Inflation during 1997-98, however, was accompanied by 'trapdoor' faulting on a steeply dipping fracture system within the caldera. Repeated trapdoor faulting over geological time has formed an arcuate intra-caldera ridge within Sierra Negra and may have acted to relax stresses above the magma chamber, inhibiting summit eruptions. Similar processes may help explain large uplift unaccompanied by eruptive activity at other volcanoes.

    View details for Web of Science ID 000090032500040

    View details for PubMedID 11069176

  • Ground deformation near Gada 'Ale Volcano, Afar, observed by Radar Interferometry GEOPHYSICAL RESEARCH LETTERS Amelung, F., Oppenheimer, C., Segall, P., Zebker, H. 2000; 27 (19): 3093-3096
  • Studying the Earth with interferometric radar COMPUTING IN SCIENCE & ENGINEERING Zebker, H. A. 2000; 2 (3): 52-60
  • Network approaches to two-dimensional phase unwrapping: intractability and two new algorithms JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION Chen, C. W., Zebker, H. A. 2000; 17 (3): 401-414

    Abstract

    Two-dimensional (2-D) phase unwrapping, that is, deducing unambiguous phase values from a 2-D array of values known only modulo 2pi, is a key step in interpreting data acquired with synthetic aperture radar interferometry. Noting the recent network formulation of the phase unwrapping problem, we apply here some well-established ideas of network theory to formalize the problem, analyze its complexity, and derive algorithms for its solution. It has been suggested that the objective of phase unwrapping should be to minimize the total number of places where unwrapped and wrapped phase gradients differ. Here we use network constructions to show that this so-called minimum L0-norm problem is NP-hard, or one that complexity theory suggests is impossible for efficient algorithms to solve exactly. Therefore we must instead find approximate solutions; we present two new algorithms for doing so. The first uses the network ideas of shortest paths and spanning trees to improve on the Goldstein et al. residue-cut algorithm [Radio Sci. 23, 713 (1988)]. Our improved algorithm is very fast, provides complete coverage, and allows user-defined weights. With our second algorithm, we extend the ideas of linear network flow problems to the nonlinear L0 case. This algorithm yields excellent approximations to the minimum L0 norm. Using interferometric data, we demonstrate that our algorithms are highly competitive with other existing algorithms in speed and accuracy, outperforming them in the cases presented here.

    View details for Web of Science ID 000085561800004

    View details for PubMedID 10708020

  • Remote sensing of volcano surface and internal processes using radar interferometry Fall Meeting of the American-Geophysical-Union Zebker, H. A., Amelung, F., Jonsson, S. AMER GEOPHYSICAL UNION. 2000: 179–205
  • Seasonal subsidence and rebound in Las Vegas Valley, Nevada observed by synthetic aperture radar interferometry Water Resources Research Hoffmann, J., Zebker, H. A., Galloway, D. L., Amelung, F. 2000
  • Widespread uplift and 'trapdoor' faulting of Galapagos volcanoes observed with radar interferometry Nature Amelung, F., Jonsson, S., Zebker, H. A., Segall, P. 2000; 407: 993-996
  • Penetration depths inferred from interferometric volume decorrelation observed over the Greenland ice sheet IEEE Trans. Geosci. Rem. Sensing Hoen, E. W., Zebker, H. A. 2000; 38: 2571-83
  • Topography-driven variations in backscatter strength and depth observed over the Greenland ice sheet with InSAR IEEE International Geoscience and Remote Sensing Symposium Hoen, E. W., Zebker, H. A. IEEE. 2000: 470–472
  • Sensing the ups and downs of Las Vegas: InSAR reveals structural control of land subsidence and aquifer-system deformation GEOLOGY Amelung, F., Galloway, D. L., Bell, J. W., Zebker, H. A., Laczniak, R. J. 1999; 27 (6): 483-486
  • A shallow-dipping dike fed the 1995 flank eruption at Fernandina Volcano, Galapagos, observed by satellite radar interferometry GEOPHYSICAL RESEARCH LETTERS Jonsson, S., Zebker, K., Cervelli, P., Segall, P., Garbeil, H., Mouginis-Mark, P., Rowland, S. 1999; 26 (8): 1077-1080
  • High-resolution water vapor mapping from interferometric radar measurements SCIENCE Hanssen, R. F., Weckwerth, T. M., Zebker, H. A., Klees, R. 1999; 283 (5406): 1297-1299
  • High-resolution water vapor mapping of clouds, fronts, and rolls from interferometric radar measurements Science Hanssen, R. F., Weckwerth, T. W., Zebker, H. A., Klees, R. 1999; 283: 1297-1299
  • Phase unwrapping algorithms for radar interferometry: Residue-cut, least-squares, and synthesis algorithms JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION Zebker, H. A., Lu, Y. P. 1998; 15 (3): 586-598
  • On the use of meteorological observations in SAR interferometry 1998 International Geoscience and Remote Sensing Symposium (IGARSS 98) on Sensing and Managing the Environment Hanssen, R., Zebker, H., Klees, R., Barlag, S. IEEE. 1998: 1644–1646
  • Imaging Radar Interferometry Manual of Remote Sensing volume 2 Zebker, H. A., Madsen, S. edited by Henderson , Lewis American Society for Photogrammetry and Remote Sensing, Wiley, New York. 1998
  • Atmospheric effects in interferometric synthetic aperture radar surface deformation and topographic maps JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH Zebker, H. A., Rosen, P. A., Hensley, S. 1997; 102 (B4): 7547-7563
  • Topography Mapping in Yearbook on Science and Technology Zebker, H., A. McGraw-Hill, New York. 1997: 1
  • Our quivering crust: tectonics from space Pacific Discovery Zebker, H., A. 1997; 50 (2): 34–36
  • Surface deformation and coherence measurements of Kilauea volcano, Hawaii, from SIR-C radar interferometry JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS Rosen, P. A., Hensley, S., Zebker, H. A., Webb, F. H., Fielding, E. J. 1996; 101 (E10): 23109-23125
  • Analysis of active lava flows on Kilauea volcano, Hawaii, using SIR-C radar correlation measurements GEOLOGY Zebker, H. A., Rosen, P., Hensley, S., MOUGINISMARK, P. J. 1996; 24 (6): 495-498
  • ANALYSIS AND EVALUATION OF THE NASA/JPL TOPSAR ACROSS-TRACK INTERFEROMETRIC SAR SYSTEM IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Madsen, S. N., Martin, J. M., Zebker, H. A. 1995; 33 (2): 383-391
  • The new dual frequency (C- and L-band) Topsar airborne interferometric SAR 1995 International Geoscience and Remote Sensing Symposium (IGARSS 95) VANZYL, J. J., Zebker, H. A., Hensley, S., HAUB, D., Wiesbeck, W. IEEE. 1995: 2270–2272
  • Analysis and evaluation of the NASA/JPL TOPSAR interferometric SAR system IEEE Transactions on Geoscience and Remote Sensing Madsen, S., N., Martin, J., Zebker, H., A. 1995; 33 (2): 383–391
  • Mission in the works promises precise global topographic data EOS Transactions Farr, T., G., Evans, D., Zebker, H., A., Harding, D., Bufton, J., Dixon, T. 1995; 76 (22): 225–228
  • MAPPING THE WORLDS TOPOGRAPHY USING RADAR INTERFEROMETRY - THE TOPSAT MISSION PROCEEDINGS OF THE IEEE Zebker, H. A., Farr, T. G., Salazar, R. P., Dixon, T. H. 1994; 82 (12): 1774-1786
  • ON THE DERIVATION OF COSEISMIC DISPLACEMENT-FIELDS USING DIFFERENTIAL RADAR INTERFEROMETRY - THE LANDERS EARTHQUAKE JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH Zebker, H. A., Rosen, P. A., Goldstein, R. M., Gabriel, A., Werner, C. L. 1994; 99 (B10): 19617-19634
  • ACCURACY OF TOPOGRAPHIC MAPS DERIVED FROM ERS-1 INTERFEROMETRIC RADAR IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Zebker, H. A., Werner, C. L., Rosen, P. A., Hensley, S. 1994; 32 (4): 823-836
  • COMPARISON OF ELEVATION DERIVED FROM INSAR DATA WITH DEM OVER LARGE RELIEF TERRAIN INTERNATIONAL JOURNAL OF REMOTE SENSING Lin, Q., Vesecky, J. F., Zebker, H. A. 1994; 15 (9): 1775-1790
  • RADAR MEASUREMENT OF FORESTED AREAS DURING OTTER REMOTE SENSING OF ENVIRONMENT Moghaddam, M., DURDEN, S., Zebker, H. 1994; 47 (2): 154-166
  • PHASE UNWRAPPING THROUGH FRINGE-LINE DETECTION IN SYNTHETIC-APERTURE RADAR INTERFEROMETRY APPLIED OPTICS Lin, Q., Vesecky, J. F., Zebker, H. A. 1994; 33 (2): 201-208

    Abstract

    Interferometric synthetic aperture radar presents a new technology for performing high-resolution topographic mapping. One of the factors critical to mapping accuracy is phase unwrapping. This paper presents a new algorithm that unwraps phase through fringe-line detection. The algorithm is effective in preventing error propagation, it preserves the image resolution, and, in the mean time, it produces negligible local errors. An edge-segment linking approach and a curve-fitting approach are investigated, and their performances are compared. Test results of the algorithm are shown with the actual interferometric SEASAT synthetic aperture radar images over large-relief terrain near Yellowstone National Park with a short baseline, and results are shown over relatively flat terrain in Death Valley of California with a long baseline.

    View details for Web of Science ID A1994MX44500008

    View details for PubMedID 20862009

  • GENERATION OF HIGH-RESOLUTION TOPOGRAPHIC MAPS OF THE GALAPAGOS-ISLANDS USING TOPSAR DATA International Geoscience and Remote Sensing Symposium on Surface and Atmospheric Remote Sensing - Technologies, Data Analysis and Interpretation (IGARSS 94) Hensley, S., Rosen, P., Zebker, H. IEEE. 1994: 704–706
  • Accuracy of topographic maps derived from ERS-1 radar interferometry IEEE Transactions on Geoscience and Remote Sensing Zebker, H., A., Werner, C., L., Rosen, P., Hensley, S. 1994; 32 (4): 823–836
  • On the derivation of coseismic displacement fields using differential radar interferometry: the Landers earthquake Journal of Geophysical Research - Solid Earth Zebker, H., A., Rosen, P., A., Goldstein, R., M., Gabriel, A., Werner, C. 1994; 99 (B10): 19617–19634
  • Mapping the world's topography using radar interferometry: the TOPSAT mission Zebker, H., A., Farr, T., G., Salazar, R., P., Dixon, T., H. 1994
  • ON THE DERIVATION OF COSEISMIC DISPLACEMENT-FIELDS USING DIFFERENTIAL RADAR INTERFEROMETRY - THE LANDERS EARTHQUAKE International Geoscience and Remote Sensing Symposium on Surface and Atmospheric Remote Sensing - Technologies, Data Analysis and Interpretation (IGARSS 94) Zebker, H. A., Rosen, P. IEEE. 1994: 286–288
  • Radar measurement of forested areas during OTTER Remote Sensing of the Environment Moghaddam, M., Durden, S., Zebker, H. 1994; 47 (2): 154–166
  • MEASUREMENT AND SIMULATION OF SIGNAL FLUCTUATIONS CAUSED BY PROPAGATION THROUGH TREES RADIO SCIENCE Durden, S. L., Klein, J. D., Zebker, H. A. 1993; 28 (6): 1049-1051
  • COMPARISON OF INTERFEROMETRIC SAR DATA WITH A DIGITAL ELEVATION MAP OVER LARGE RELIEF TERRAIN International Space Year Conference on Earth and Space Science Information Systems Lin, Q., Vesecky, J. F., Zebker, H. A. AIP PRESS. 1993: 207–15
  • TOPOGRAPHIC MAPPING USING RADAR INTERFEROMETRY - PROCESSING TECHNIQUES IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Madsen, S. N., Zebker, H. A., Martin, J. 1993; 31 (1): 246-256
  • Measurement and simulation of signal fluctuations caused by propagation through trees Radio Science Durden, S., L., Klein, J., D., Zebker, H., A. 1993; 28 (6): 1049–1051
  • EFFECTS OF ENVIRONMENTAL-CHANGE ON RADAR BACKSCATTER IN THE OREGON TRANSECT 13th Annual International Geoscience and Remote Sensing Symposium (IGARSS 93) Moghaddam, M., DURDEN, S., Zebker, H. IEEE. 1993: 580–582
  • Topographic mapping using radar interferometry: processing techniques IEEE Trans. Geosci. Rem. Sensing Madsen, S., N., Zebker, H., A., Martin, J. 1993; 31 (1): 246–256
  • THE TOPSAR INTERFEROMETRIC RADAR TOPOGRAPHIC MAPPING INSTRUMENT IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Zebker, H. A., Madsen, S. N., Martin, J., Wheeler, K. B., Miller, T., Lou, Y. L., Alberti, G., Vetrella, S., Cucci, A. 1992; 30 (5): 933-940
  • DECORRELATION IN INTERFEROMETRIC RADAR ECHOES IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Zebker, H. A., Villasenor, J. 1992; 30 (5): 950-959
  • NEW APPROACHES IN INTERFEROMETRIC SAR DATA-PROCESSING IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Lin, Q., Vesecky, J. F., Zebker, H. A. 1992; 30 (3): 560-567
  • CALIBRATION OF STOKES AND SCATTERING MATRIX FORMAT POLARIMETRIC SAR DATA IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Freeman, A., VANZYL, J. J., Klein, J. D., Zebker, H. A., Shen, Y. 1992; 30 (3): 531-539
  • PHASE UNWRAPPING THROUGH LEAST-SQUARES APPROXIMATION CONF ON IMAGE PROCESSING ALGORITHMS AND TECHNIQUES 3 Lin, Q., Vesecky, J. F., Zebker, H. A. SPIE - INT SOC OPTICAL ENGINEERING. 1992: 244–255
  • RADIOMETRIC CORRECTION OF SAR-IMAGES OF VARYING TERRAIN HEIGHTS 12TH ANNUAL INTERNATIONAL SYMP ON GEOSCIENCE AND REMOTE SENSING ( IGARSS 92 ) Freeman, A., Moghaddam, M., Zink, M., Zebker, H. I E E E. 1992: 271–273
  • Calibration of Stokes and scattering matrix format polarimetric SAR data IEEE Trans. Geosci. Rem. Sensing Freeman, A., van Zyl, J., J., Klein, J., Zebker, H., A., Shen, Y. 1992; 30 (3): 531–539
  • Radar interferometric studies of the Earth's topography EOS Evans, D., L., Farr, T., G., Zebker, H., A., Mouginis-Mark, P., J. 1992; 73 (52): 553, 557–558
  • TOPOGRAPHIC MAPPING FROM ERS-1 AND SEASAT-RADAR INTERFEROMETRY 12TH ANNUAL INTERNATIONAL SYMP ON GEOSCIENCE AND REMOTE SENSING ( IGARSS 92 ) Zebker, H. A., Villasenor, J., Madsen, S. N. I E E E. 1992: 387–388
  • RADAR MEASUREMENT OF FORESTED AREAS DURING OTTER 12TH ANNUAL INTERNATIONAL SYMP ON GEOSCIENCE AND REMOTE SENSING ( IGARSS 92 ) Moghaddam, M., DURDEN, S., Zebker, H., Klein, J. I E E E. 1992: 1135–1137
  • TEMPORAL DECORRELATION IN REPEAT-PASS RADAR INTERFEROMETRY 12TH ANNUAL INTERNATIONAL SYMP ON GEOSCIENCE AND REMOTE SENSING ( IGARSS 92 ) Villasenor, J., Zebker, H. I E E E. 1992: 941–943
  • Decorrelation in interferometric radar echoes IEEE Trans. Geo. Rem. Sensing Zebker, H., A., Villasenor, J. 1992; 30 (5): 950–959
  • STUDIES OF TEMPORAL CHANGE USING RADAR INTERFEROMETRY CONF ON SYNTHETIC APERTURE RADAR Villasenor, J., Zebker, H. A. SPIE - INT SOC OPTICAL ENGINEERING. 1992: 187–198
  • AUTOMATED ABSOLUTE PHASE RETRIEVAL IN ACROSS-TRACK INTERFEROMETRY 12TH ANNUAL INTERNATIONAL SYMP ON GEOSCIENCE AND REMOTE SENSING ( IGARSS 92 ) Madsen, S. N., Zebker, H. A. I E E E. 1992: 1582–1584
  • THE TOPSAR INTERFEROMETRIC RADAR TOPOGRAPHIC MAPPING INSTRUMENT 12TH ANNUAL INTERNATIONAL SYMP ON GEOSCIENCE AND REMOTE SENSING ( IGARSS 92 ) Zebker, H. A., Madsen, S. N., Martin, J., Alberti, G., Vetrella, S., Cucci, A. I E E E. 1992: 1595–1597
  • CALIBRATED IMAGING RADAR POLARIMETRY - TECHNIQUE, EXAMPLES, AND APPLICATIONS IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Zebker, H. A., VANZYL, J. J., Durden, S. L., NORIKANE, L. 1991; 29 (6): 942-961
  • IMAGING RADAR POLARIMETRY - A REVIEW PROCEEDINGS OF THE IEEE Zebker, H. A., VANZYL, J. J. 1991; 79 (11): 1583-1606
  • POLARIMETRIC RADAR MEASUREMENTS OF A FORESTED AREA NEAR MT SHASTA IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Durden, S. L., Klein, J. D., Zebker, H. A. 1991; 29 (3): 444-450
  • ANALYSIS OF ACTIVE VOLCANOS FROM THE EARTH OBSERVING SYSTEM REMOTE SENSING OF ENVIRONMENT MOUGINISMARK, P., Rowland, S., Francis, P., Friedman, T., Garbeil, H., Gradie, J., Self, S., Wilson, L., Crisp, J., Glaze, L., Jones, K., Kahle, A., Pieri, D., Zebker, H., Krueger, A., Walter, L., Wood, C., Rose, W., Adams, J., Wolff, R. 1991; 36 (1): 1-12
  • TOPOGRAPHY ESTIMATION WITH INTERFEROMETRIC SYNTHETIC APERTURE RADAR USING FRINGE DETECTION 1991 INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMP - REMOTE SENSING : GLOBAL MONITORING FOR EARTH MANAGEMENT ( IGARSS 91 ) Lin, Q., Vesecky, J. F., Zebker, H. A. I E E E. 1991: 2173–2176
  • K-distribution and multifrequency polarimetric terrain radar clutter J. Electromagnetic Waves and Applications Yueh, S., H., Kong, J., A., Jao, J., K., Shin, R., T., Zebker, H., A., Le Toan, T. 1991; 5 (1): 1–15
  • Imaging radar polarimetry Zebker, H., A., van Zyl, J., J. 1991
  • Radar measurement of L-band signal fluctuations caused by propagation through trees IEEE Trans. Ant. Prop. Durden, S., L., Klein, J., D., Zebker, H., A. 1991; 39 (10): 1537–39
  • Polarimetric radar measurements of a forested area near Mt. Shasta IEEE Trans. Geosci. Rem. Sensing Durden, S., L., Klein, J., D., Zebker, H., A. 1991; 29 (3): 444–450
  • Calibrated imaging radar polarimetry: technique, examples, and applications IEEE Trans. Geosci. Rem. Sensing Zebker, H., A., van Zyl, J., J., Durden, S., L., Norikane, L. 1991; 29 (6): 942–961
  • Analysis of active volcanoes from the Earth Observing System Remote Sensing of the Environment Mouginis-Mark, P., Rowland, S., Francis, P., Friedman, T., Gradie, J., Self, S., Zebker, Howard, A. 1991; 36: 1–12
  • PHASE CALIBRATION OF IMAGING RADAR POLARIMETER STOKES MATRICES IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Zebker, H. A., Lou, Y. L. 1990; 28 (2): 246-252
  • Phase calibration of imaging radar polarimeter Stokes matrices IEEE Trans. Geosci. Rem. Sens. Zebker, H., A., Lou, Y. 1990; 28 (2): 246–252
  • The unpolarized component in polarimetric radar observations of forested areas IEEE Trans. Geosci. Rem. Sens. Durden, S., L., van Zyl, J., J., Zebker, H., A. 1990; 28 (2): 268–271
  • Polarimetric Radar System Design Radar Polarimetry for Geoscience Applications, Polarimetric SAR Systems, and parts of Chapter 7 Zebker, H., A., van Zyl, J., J., Elachi, C. edited by Ulaby, F., T., Elachi, C. Artech House, Inc., Norwood. 1990: 1
  • Imaging Radar Polarimetry Progress in Electromagnetics Research: Radar Polarimetry van Zyl, J., J., Zebker, H., A. edited by Kong, J., A. Elsevier Science, New York. 1990: 1
  • K-Distribution and Polarimetric Terrain Radar Clutter Progress in Electromagnetics Research: Radar Polarimetry Yueh, S., H., Kong, J., A., Jao, J., K., Shin, R., T., Zebker, H., A., Le Toan, T. edited by Kong, J., A. Elsevier Science, New York. 1990: 1
  • Polarimetric SAR Applications Radar Polarimetry for Geoscience Applications van Zyl, J., J., Zebker, H., A., Elachi, C. edited by Ulaby, F., T., Elachi, C. Artech House, Inc., Norwood. 1990: 1
  • REMOTE-SENSING OF OCEAN CURRENTS SCIENCE Goldstein, R. M., Barnett, T. P., Zebker, H. A. 1989; 246 (4935): 1282-1285

    Abstract

    A method of remotely measuring near-surface ocean currents with a synthetic aperture radar (SAR) is described. The apparatus consists of a single SAR transmitter and two receiving antennas. The phase difference between SAR image scenes obtained from the antennas forms an interferogram that is directly proportional to the surface current. The first field test of this technique against conventional measurements gives estimates of mean currents accurate to order 20 percent, that is, root-mean-square errors of 5 to 10 centimeters per second in mean flows of 27 to 56 centimeters per second. If the full potential of the method could be realized with spacecraft, then it might be possible to routinely monitor the surface currents of the world's oceans.

    View details for Web of Science ID A1989CC89000035

    View details for PubMedID 17832222

  • MAPPING SMALL ELEVATION CHANGES OVER LARGE AREAS - DIFFERENTIAL RADAR INTERFEROMETRY JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS Gabriel, A. K., Goldstein, R. M., Zebker, H. A. 1989; 94 (B7): 9183-9191
  • MODELING AND OBSERVATION OF THE RADAR POLARIZATION SIGNATURE OF FORESTED AREAS IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Durden, S. L., VANZYL, J. J., Zebker, H. A. 1989; 27 (3): 290-301
  • Mapping small elevation changes over large areas: Differential radar interferometry J. Geophys. Res. Gabriel, A., G., Goldstein, R., M., Zebker, H., A. 1989; 94 (B7): 9183–91
  • Remote sensing of ocean currents Science Goldstein, R., M., Barnett, T., P., Zebker, H., A. 1989; 246: 1282–85
  • Modeling and observation of forest radar polarization signatures IEEE Trans. Geosci. Rem. Sens. Durden, S., L., Zebker, H., A., van Zyl, J., J. 1989; 27 (3): 290–301
  • RADAR POLARIMETRY - ANALYSIS TOOLS AND APPLICATIONS IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Evans, D. L., Farr, T. G., VANZYL, J. J., Zebker, H. A. 1988; 26 (6): 774-789
  • SATELLITE RADAR INTERFEROMETRY - TWO-DIMENSIONAL PHASE UNWRAPPING RADIO SCIENCE Goldstein, R. M., Zebker, H. A., Werner, C. L. 1988; 23 (4): 713-720
  • Imaging radar polarimetry: analysis tools and applications IEEE Trans. Geosci. Rem. Sens. Evans, D., L., Farr, T., G., van Zyl, J., J., Zebker, H., A. 1988; 26 (6): 774–789
  • Satellite radar interferometry: two dimensional phase unwrapping Radio Science Goldstein, R., M., Zebker, H., A., Werner, C., L. 1988; 23 (4): 713–720
  • INTERFEROMETRIC RADAR MEASUREMENT OF OCEAN SURFACE CURRENTS NATURE Goldstein, R. M., Zebker, H. A. 1987; 328 (6132): 707-709
  • IMAGING RADAR POLARIZATION SIGNATURES - THEORY AND OBSERVATION RADIO SCIENCE VANZYL, J. J., Zebker, H. A., Elachi, C. 1987; 22 (4): 529-543
  • IMAGING RADAR POLARIMETRY FROM WAVE SYNTHESIS JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS Zebker, H. A., VANZYL, J. J., HELD, D. N. 1987; 92 (B1): 683-701
  • Interferometric radar measurement of ocean surface currents Nature Goldstein, R., M., Zebker, H., A. 1987; 328: 707–9
  • Imaging radar polarimetry: Forested areas. Volume I. Polarimetric observations A catalog of observed polarimetric scattering behavior for various forest and man-made targets, prepared under contract for U.S. Army Harry Diamond Laboratories, Jet Propulsion Laboratory, Pasadena Dubois, P., C., Durden, S., L., Zebker, H., A., van Zyl, J., J. 1987
  • Imaging Radar Polarimetry from Wave Synthesis J. Geophys. Res. Zebker, H., A., van Zyl, J., J., Held, D., N. 1987; B2 (91): 683–701
  • Radar polarimeter measures orientation of calibration corner reflectors Zebker, H., A., Norikane, L. 1987
  • TOPOGRAPHIC MAPPING FROM INTERFEROMETRIC SYNTHETIC APERTURE RADAR OBSERVATIONS JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS Zebker, H. A., Goldstein, R. M. 1986; 91 (B5): 4993-4999
  • Imaging Radar Polarimetry Short instructional film illustrating radar polarization principles and techniques, Jet Propulsion Laboratory Zebker, H., A., Burnette, F. 1986
  • Topographic Mapping Derived from Synthetic Aperture Radar Measurements J. Geophys. Res. Zebker, H., A., Goldstein, R., M. 1986; 91: 4993–9
  • SATURN RINGS - PARTICLE-SIZE DISTRIBUTIONS FOR THIN-LAYER MODELS ICARUS Zebker, H. A., Marouf, E. A., Tyler, G. L. 1985; 64 (3): 531-548
  • THICKNESS OF SATURNS RINGS INFERRED FROM VOYAGER-1 OBSERVATIONS OF MICROWAVE SCATTER SCIENCE Zebker, H. A., Tyler, G. L. 1984; 223 (4634): 396-398

    Abstract

    Earth-based telescopic observations indicate that Saturn's rings are about 1 kilometer thick, while spacecraft measurements and theoretical considerations give an upper bound of about 100 meters. Analysis of a shielding effect present in radio occultation provides a sensitive new measure of the ring thickness. On the basis of this effect, Voyager 1 microwave measurements of near-forward scatter imply a thickness ranging from less than 10 meters in ring C to about 20 and 50 meters in the Cassini division and ring A, respectively. Monolayer models do not fit the observations in the latter two regions. The discrepancy between the Earth-based and spacecraft measurements may be due to warps in the ring plane or effects of tenuous material outside the primary ring system.

    View details for Web of Science ID A1984RZ10900030

    View details for PubMedID 17829889

  • SATURNS RINGS - VOYAGER-1 RADIO OCCULTATION EXPERIMENT RESULTS IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING Simpson, R. A., Tyler, G. L., Marouf, E. A., Zebker, H. A., Eshleman, V. R. 1984; 22 (6): 656-665
  • ON OBTAINING THE FORWARD PHASE FUNCTIONS OF SATURN RING FEATURES FROM RADIO OCCULTATION OBSERVATIONS ICARUS Zebker, H. A., Tyler, G. L., Marouf, E. A. 1983; 56 (2): 209-228
  • PARTICLE-SIZE DISTRIBUTIONS IN SATURNS RINGS FROM VOYAGER-1 RADIO OCCULTATION ICARUS Marouf, E. A., Tyler, G. L., Zebker, H. A., Simpson, R. A., ESHLEMAN, V. 1983; 54 (2): 189-211
  • THE MICROWAVE OPACITY OF SATURNS RINGS AT WAVELENGTHS OF 3.6 AND 13 CM FROM VOYAGER-1 RADIO OCCULTATION ICARUS Tyler, G. L., Marouf, E. A., Simpson, R. A., Zebker, H. A., ESHLEMAN, V. 1983; 54 (2): 160-188