Bio


I am currently a Post-Doctoral Researcher at the Department of Earth System Science, Stanford University. I work with Prof. Morgan O'Neill and my research lies at the crossroads of Tropical Cyclones, Geofluid Dynamics, Monsoon Dynamics, and Complex Systems. I seek to address fundamental, trans-disciplinary research questions pertaining to these areas.

Prior to joining Stanford, I was a NASA Earth Science Doctoral Fellow at Purdue University. My Ph.D. advisors were Prof. Dan Chavas (Purdue) and Dr. Frank Marks (Hurricane Research Division, NOAA). My doctoral research characterized the impact of vortex-scale and sub-vortex-scale azimuthal asymmetries (eddies) during periods of rapid intensity changes in tropical cyclones (TCs). I investigated the spatial, spectral, and temporal aspects of these asymmetries; developed novel techniques to model the scale-specific stochasticity and cross-scale feedbacks across the vortex-scale and sub-vortex scale eddies within a TC vortex; computed the relative roles of the external and intrinsic drivers of TC rapid intensity changes; and developed a new approach to compute the non-stationary probabilities of TC intensity transitions. From a forecasting perspective, these advancements drive the development of diagnostics or early warning signals that allow us to examine and characterize an asymmetric TC vortex and predict if it is going to rapidly intensify or weaken with x% probability.

I obtained an M.Sc. in Computational Fluid Mechanics from Imperial College London. For my Master's thesis, I worked under the supervision of Prof. Spencer Sherwin and used High-Order Spectral element techniques to understand the multi-scale transfer of energy in decaying homogeneous turbulence. I have a Bachelors in Mechanical Engineering from SASTRA University, India. I visited MIT to pursue my Bachelor's thesis under the supervision of Prof. Sanjay Sarma. At MIT, I designed, developed, and tested a Contact type, Pressure Difference - based leak detector, that was to be deployed in Public Water Distribution Systems. Prior to that, I was as an Indian Academy of Sciences Research Fellow and I worked with Prof. Gautam Biswas on Computational Vortex-Dynamics and self-sustained oscillatory flows in Heat Exchangers.

Apart from being a researcher, I am a musician (composer/arranger/producer and a keyboardist), and an avid sports fan (basketball, cricket, soccer). Conversations are my tonic, so please get in touch if you are interested in what I do.

Honors & Awards


  • Bilsland Dissertation Fellow, Purdue University (2018)
  • NASA Earth Science Doctoral Fellow, Purdue University (2015 - 2018)
  • Lynn Fellow, Purdue University (2014 - 2015)
  • President's Ambassador, Imperial College London (2012 - 2013)
  • Desh-Videsh Scholarship, Semester Abroad Programme, Massachusetts Institute of Technology and SASTRA University, India (2012)
  • Indian Academy of Sciences Research Fellow, Indian Academy of Sciences (2009 - 2010)

Professional Education


  • Master of Science, Imperial College of Science, Technology & Medicine (2013)
  • Doctor of Philosophy, Purdue University (2018)

Lab Affiliations


All Publications


  • On the processes influencing rapid intensity changes of tropical cyclones over the Bay of Bengal SCIENTIFIC REPORTS Bhalachandran, S., Nadimpalli, R., Osuri, K. K., Marks, F. D., Gopalakrishnan, S., Subramanian, S., Mohanty, U. C., Niyogi, D. 2019; 9: 3382

    Abstract

    We present a numerical investigation of the processes that influenced the contrasting rapid intensity changes in Tropical Cyclones (TC) Phailin and Lehar (2013) over the Bay of Bengal. Our emphasis is on the significant differences in the environments experienced by the TCs within a few weeks and the consequent differences in their organization of vortex-scale convection that resulted in their different rapid intensity changes. The storm-relative proximity, intensity, and depth of the subtropical ridge resulted in the establishment of a low-sheared environment for Phailin and a high-sheared environment for Lehar. Our primary finding here is that in Lehar's sheared vortex, the juxtaposition in the azimuthal phasing of the asymmetrically distributed downward eddy flux of moist-entropy through the top of the boundary layer, and the radial eddy flux of moist-entropy within the boundary layer in the upshear left-quadrant of Lehar (40-80 km radius) establishes a pathway for the low moist-entropy air to intrude into the vortex from the environment. Conversely, when the azimuthal variations in boundary layer moist-entropy, inflow, and convection are weak in Phailin's low-sheared environment, the inflow magnitude and radial location of boundary layer convergence relative to the radius of maximum wind dictated the rapid intensification.

    View details for DOI 10.1038/s41598-019-40332-z

    View details for Web of Science ID 000460123600054

    View details for PubMedID 30833683

    View details for PubMedCentralID PMC6399276

  • The Relative Importance of Factors Influencing Tropical Cyclone Rapid Intensity Changes GEOPHYSICAL RESEARCH LETTERS Bhalachandran, S., Haddad, Z. S., Hristova-Veleva, S. M., Marks, F. D. 2019; 46 (4): 2282–92
  • An Eye on the Storm: Uncovering Multi-Variate Relationships with a Science-Driven System For Interactive Analysis and Visualization; Motivating Machine-Learning Discoveries for Hurricane Rapid Intensity Changes IEEE International Geoscience and Remote Sensing Symposium Hristova-Veleva, S., et al 2019: 5413–16
  • Paradoxical impact of sprawling intra-Urban Heat Islets: Reducing mean surface temperatures while enhancing local extremes. Scientific reports Shreevastava, A., Bhalachandran, S., McGrath, G. S., Huber, M., Rao, P. S. 2019; 9 (1): 19681

    Abstract

    Extreme heat is one of the deadliest health hazards that is projected to increase in intensity and persistence in the near future. Here, we tackle the problem of spatially heterogeneous heat distribution within urban areas. We develop a novel multi-scale metric of identifying emerging heat clusters at various percentile-based thermal thresholds and refer to them collectively as intra-Urban Heat Islets. Using remotely sensed Land Surface Temperatures, we first quantify the spatial organization of heat islets in cities at various degrees of sprawl and densification. We then condense the size, spacing, and intensity information about heterogeneous clusters into probability distributions that can be described using single scaling exponents (denoted by β, [Formula: see text], and λ, respectively). This allows for a seamless comparison of the heat islet characteristics across cities at varying spatial scales and improves on the traditional Surface Urban Heat Island (SUHI) Intensity as a bulk metric. Analysis of Heat Islet Size distributions demonstrates the emergence of two classes where the dense cities follow a Pareto distribution, and the sprawling cities show an exponential tempering of Pareto tail. This indicates a significantly reduced probability of encountering large heat islets for sprawling cities. In contrast, analysis of Heat Islet Intensity distributions indicates that while a sprawling configuration is favorable for reducing the mean SUHI Intensity of a city, for the same mean, it also results in higher local thermal extremes. This poses a paradox for urban designers in adopting expansion or densification as a growth trajectory to mitigate the UHI.

    View details for DOI 10.1038/s41598-019-56091-w

    View details for PubMedID 31873119

    View details for PubMedCentralID PMC6928021

  • Characterizing the energetics of vortex-scale and sub-vortex-scale asymmetries during tropical cyclone rapid intensity changes Journal of the Atmospheric Sciences Bhalachandran, S., Chavas, D., Marks, F., Dubey, S., Shreevastava, A., Krishnamurti, T. 2019

    View details for DOI 10.1175/JAS-D-19-0067.1

  • A Conceptual Framework for the Scale‐Specific Stochastic Modeling of Transitions in Tropical Cyclone Intensities Earth and Space Science Bhalachandran, S., Rao, P., Marks, F. D. 2019; 6 (6): 972-981

    View details for DOI 10.1029/2019EA000585

  • WUDAPT An Urban Weather, Climate, and Environmental Modeling Infrastructure for the Anthropocene BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY Ching, J., Mills, G., Bechtel, B., See, L., Feddema, J., Wang, X., Ren, C., Brousse, O., Martilli, A., Neophytou, M., Mouzourides, P., Stewart, I., Hanna, A., Ng, E., Foley, M., Alexander, P., Aliaga, D., Niyogi, D., Shreevastava, A., Bhalachandran, P., Masson, V., Hidalgo, J., Fung, J., Andrade, M., Baklanov, A., Dai, W., Milcinski, G., Demuzere, M., Brunsell, N., Pesaresi, M., Miao, S., Mu, Q., Chen, F., Theeuwes, N. 2018; 99 (9): 1907–28
  • A low-wavenumber analysis of the relative roles of the environmental and vortex-scale variables responsible for rapid intensity changes in landfalling tropical cyclones Saiprasanth, B., Haddad, Z. S., Hristova-Veleva, S., Marks, F. D., Liu, G., Haddad, Z. S. SPIE-INT SOC OPTICAL ENGINEERING. 2018

    View details for DOI 10.1117/12.2500290

    View details for Web of Science ID 000453911300005

  • Fast Weather Simulation for Inverse Procedural Design of 3D Urban Models ACM TRANSACTIONS ON GRAPHICS Garcia-Dorado, I., Aliaga, D. G., Bhalachandran, S., Schmid, P., Niyogi, D. 2017; 36 (2)

    View details for DOI 10.1145/2999534

    View details for Web of Science ID 000400160000009