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Description:

Tropical Cyclones (TCs) are the product of complex multi-scale processes and interactions. The role of the environment has long been recognized. However, recent advances in analyzing and predicting the evolution of TCs suggest that the distribution and intensity of convective activity in the storm have an important role in determining the storm's evolution, intensity and size. Yet, understanding of these processes and non-linear interactions is still lacking. The research community foresees that future progress will come with properly accounting for the observations of the environment and of the inner-core processes which themselves are influenced by the environment (e.g. moisture, shear, etc.).  This brings to the forefront the need to investigate the important role of the convective organization, particularly with respect to the dynamically-significant vortex structure and environmental shear.

Forecasting TC evolution today is very often focused on analyzes of the cloud patterns in IR geostationary data. However, IR observations are mostly sensitive to the cloud shield and cannot properly reveal the details in the dynamically-significant organization of the deep and intense convection that grows under this cloud shield. Observations from low-Earth-orbit (LEO) microwave radiometers, readily available today, can provide the missing information. The challenge to understanding the role convection plays in TC evolution is in relating the IR data to the convective organization revealed by the passive microwave observations, to improve the analysis of these storms (amount, intensity and organization of convection in relation to different IR-detected cloud patterns).  Establishing relationships between the large-scale environment and the storm-scale organization of convection will help improve the predictability of TC evolution in the near term.

The successful candidate will collect a comprehensive set of satellite observations of named Tropical Storms and tropical depressions from 1999 – 2022. The dataset will include: geostationary IR data; passive microwave observations from LEO satellites; concurrent reanalysis fields. She/he will develop analyses tools and metrics to test several hypotheses presented in the literatures and then develop new hypotheses, if needed. He/she will join a group of scientists working on similar research and will collaborate with them.  He/she will prepare journal papers and participate in the development of new proposals.

References: 

Haddad, Z. S., R. Sawaya, S. Kacimi, O.O. Sy, F. J. Turk and J. Steward, 2017: Interpreting mm-wave radiances over tropical convective clouds. J. Geophys. Res. ? Atmos. 122, 1650-1654 (doi:10.1002/2016JD025923)
Haddad, Z. S., O.O. Sy, S. Hristova-Veleva, and G.L. Stephens, 2017: Derived observations from frequently-sampled microwave measurements of precipitation. Part I: Relations to atmospheric thermodynamics. IEEE Trans. Geosci. Rem. Sens. 55, 3441-3453 (doi: 10.1109/TGRS.2017.2672825)
Hristova-Veleva, S. M., Z. S. Haddad, B. W. Stiles, T. P. J. Shen, N. Niamsuwan, F. J. Turk, P. P. Li, B. W. Knosp, Q. A. Vu, B. H. Lambrigtsen, and W. L. Poulsen, 2016: Possible predictors for the rapid intensification and evolution of hurricanes from near-coincident satellite observations of the structure of precipitation and surface winds: Hurricane Joaquin, 32nd AMS Conference on Hurricanes and Tropical Meteorology, San Juan, PR https://ams.confex.com/ams/32Hurr/webprogram/Paper293955.html
Hristova-Veleva, S. M., and Coauthors, 2020: An eye on the storm: Integrating a wealth of data for quickly advancing the physical understanding and forecasting of tropical cyclones. Bull. Amer. Meteor. Soc., 101, https://doi.org/10.1175/BAMS-D-19-0020.1 
Hristova-Veleva, S., Z. Haddad, A. Chau, B. W. Stiles, F. J. Turk, P. P. Li , B. Knosp, Q. Vu, T.-P. Shen, B. Lambrigtsen, E.-K. Seo, H. Su, 2021: “Impact of microphysical parameterizations on simulated hurricanes: Using multiparameter satellite data to determine the Particle Size Distributions that produce most realistic storms”. Atmosphere 2021, 12, 154. https://doi.org/10.3390/atmos12020154
Kieper, M. E., and H. Jiang, 2012: Predicting tropical cyclone rapid intensification using the 37 Ghz ring pattern identified from passive microwave measurements, Geophys. Res. Lett., 39, L13804, doi:10.1029/2012GL052115.
Lonfat, M., F.D. Marks, and S.S.Chen, 2004: "Precipitation Distribution in Tropical Cyclones using the Tropical Rainfall Measuring Mission (TRMM) microwave imager : A Global Perspective" Mon.Wea.Review 132(7) p.1645-1660 (July 2004)
Nolan, D., 2011: Evaluating environmental favorableness for tropical cyclone development with the method of point downscaling. J. Adv. Model. Earth Syst., 3, M08001, doi:10.1029/2011MS000063.
Tao, D., and F. Zhang, 2014:  Effect of environmental shear, sea-surface temperature and ambient moisture on the formation and predictability of tropical cyclones: an ensemble-mean perspective. Journal of Advances in Modeling Earth Systems.
Wu, Longtao, H. Su, R. G. Fovell, B. Wang, J. T. Shen, B. H. Kahn, S. M. Hristova-Veleva, B. H. Lambrigtsen, E. J. Fetzer, J. H. Jiang, 2012: “Relationship of Environmental Relative Humidity with Tropical Cyclone Intensity and Intensification Rate over North Atlantic”, Geophys. Res. Lett., 39, L20809, doi:10.1029/2012GL05

Field of Science: Earth Science

Advisors:
Hristova-Veleva, Svetla 
svetla.hristova@jpl.nasa.gov
(818) 354-7314

Applications with citizens from Designated Countries will not be accepted at this time, unless they are Legal Permanent Residents of the United States. A complete list of Designated Countries can be found at: https://www.nasa.gov/oiir/export-control.

Eligibility is currently open to: 

• U.S. Citizens; 
• U.S. Lawful Permanent Residents (LPR);  
• Foreign Nationals eligible for an Exchange Visitor J-1 visa status; and, 
• Applicants for LPR, asylees, or refugees in the U.S. at the time of application with 1) a valid EAD card and 2) I-485 or I-589 forms in pending status 

• Degree: Doctoral Degree.