Join us for a virtual seminar by Dr. Joe Turk, Jet Propulsion Laboratory (JPL), California Institute of Technology. At JPL, he is a member of the Radar Science and Engineering section. His talk is titled "Moisture in the Lower Free Troposphere and Observational Strategies for Obtaining Vertical Profiles In and Near Convection."
Date and Time: Thursday, April 13, 2023 at 11:00am
Join us via Teams.
Abstract:
Recent developments indicate that moisture in the lower free troposphere (LFT) strongly affects deep convection. This basic process introduces observational constraints, due challenges in obtaining high-vertical resolution profiles of moisture and temperature in and near convective weather. In addition to identifying layers of influence, such observations would serve as diagnostics for the parameterization of convection in climate and weather forecast models by characterizing the dependence of convection on the humidity-temperature environment.
To address these constraints, the use of Global Navigation Satellite System (GNSS) polarimetric radio occultation (PRO) measurements is explained. A closely-spaced sequence of PRO satellite observations would capture independent profiles of coordinated temperature, moisture and precipitation within convection and its environment. Similar to the principle underlying polarimetric weather radar, PRO relies upon hydrometeor shape asymmetry, such that a differential phase time delay is induced between the horizontal- and vertically-polarized radio signals propagating through a precipitation medium. The PRO concept has been demonstrated by the Radio Occultations and Heavy Precipitation (ROHP) experimental receiver orbiting onboard the Spanish PAZ satellite since May 2018. Highlights from the past four years of ROHP analysis will be presented, as well as applications for these data in weather modeling.
Biography:
Dr. Joe Turk is a member of the Radar Science and Engineering section at the Jet Propulsion Laboratory (JPL). His overall primary interest is atmospheric passive/active remote sensing related to clouds and precipitation, and the observations needed to improve their representation in weather and climate models. Prior to JPL, he worked for the Naval Research Laboratory's Marine Meteorology Division. He has been active in NASA's TRMM and GPM science teams, served as an editor for the AMS Journal of Hydrometeorology, and has been active in the organization of the CGMS/WMO International Precipitation Working Group since its inception. He received his undergraduate degrees from Michigan Technological University and, after a period in industry, his PhD from Colorado State University (electrical engineering), where he became interested in radar meteorology using the CSU and NCAR S-band polarimetric radar systems. When not analyzing the treasure trove of information buried in the archive of NASA's environmental satellite data, you can often find him on his bike exploring the hills and mountains of Southern California.
For more information on the GESTAR II Seminar Series, click here.
