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Grab some lunch and join JPL Postdoctoral Fellow Kevin Nelson, who will discuss his work and research on enhancing tropical cyclone intensity forecasts with GNSS Radio Occultation data. (see additional Teams information below).Main Idea: New data on asteroid positions is 1-2 orders of magnitude more precise than usual. To process these datasets, models of observation and asteroid motion must be improved. New observations are precise enough that the illumination phase/shape becomes relevant. Large asteroids deviate small asteroids in close approaches. This deflection is detectable and allows us to estimate asteroid masses, such as asteroid 16 Psyche among others.
Abstract: Long-range tropical cyclone (TC) intensity forecasts remain one of the biggest challenges in numerical weather prediction models and forecast errors have been attributed to several observational deficits. Previous studies have noted that the TC middle troposphere is under-observed and that remote sensing techniques are ideal for filling the observational gaps left by dropsondes. Vertical profiling of TC thermodynamics from conventional passive microwave and infrared sensors has historically been limited due to coarse vertical resolution as well as signal degradation from clouds and precipitation. High vertical resolution Global Navigation Satellite System (GNSS) radio occultation (RO) soundings are insensitive to clouds and precipitation, providing a unique opportunity to study the TC thermodynamic vertical structure.
In this study, GNSS RO profiles from COSMIC-1 (2006–2019) and COSMIC-2 (2019–2023), colocated with TC tracks, are analyzed in conjunction with dropsondes and model reanalysis in the TC environment, and any biases are assessed. Vertical profiles of atmospheric refractivity, temperature, and moisture, binned radially outward from the center of their respective TCs, are used to create median profile composites at each distance. Subsets of the colocated profiles are also used to determine differences in vertical thermodynamic structure between different TC intensities and TC quadrants. The temporal evolution of individual storms and composites is also considered to determine whether intensification processes are observable from RO. A more complete understanding of the vertical thermodynamic structure of the TC middle troposphere and its evolution over time will likely improve model representation and reduce forecast errors.
About the speaker: Kevin Nelson received his B.S. in Meteorology from Florida Institute of Technology in 2012 and his M.S. in Atmospheric Science from University of Kansas. He finished his schooling in August 2022, with a Ph.D. from Texas A&M University – Corpus Christi (TAMUCC) in Coastal and Marine System Science, with a focus in Atmospheric Science. Kevin’s research focuses on the use of GNSS Radio Occultation to examine the planetary boundary layer, its height, and thermodynamic characteristics. Additionally, his research uses GNSS RO to examine tropical cyclone thermodynamics structure and assess the quality of RO observations in extremely moist environments. His other interests include severe weather, extreme precipitation characterization, neutral atmosphere RO retrievals using novel balloon-borne and airborne platforms and using new polarimetric radio occultation observations to characterize precipitation features in the atmosphere. Kevin is also passionate about software development, where his current JPL projects include developing a formal 1D variational retrieval for pressure, temperature, and water vapor pressure from RO data for JPL RO processing as well as development and validation of new PBL products as part of a Satellite Needs Working Group project. Kevin is an avid video gamer and volleyball player. His other interests also include science/STEM education and activism, LGBTQ+ rights activism, and finding new restaurants.
Teams information:
Meeting ID: 243 888 387 517
Passcode: Ta9kg7Gv
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Event Venue
Online event, 4800 Oak Grove Dr, La Canada Flintridge, CA 91011, United States,La Canada Flintridge, California, La Canada Flintridge, California
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