Remote Sensing the Thermal and Humidity Structure of the Earth's Atmosphere Using the GPS Radio Occultation Technique: Applications in Climate Studies

This presentation introduces the fundamentals of the Global Positioning System radio occultation (GPS RO) remote sensing technique in retrieving atmospheric temperature and humidity information and presents the use of these observations in climate research. Our objective is to demonstrate and establish the GPS RO remote sensing technique as a complementary data set to existing state-of-the-art space-based platforms for climate studies. We show how GPS RO measurements at 1.2-1.6 GHz frequency band can be used to infer the upper tropospheric water vapor and temperature feedbacks and we present a decade-long specific humidity (SH) record from January 2007 until December 2015. We cross-compare the GPS RO-estimated climate feedbacks and the SH long-record with independent data sets from the Modern-Era Retrospective Analysis for Research and Applications (MERRA), the European Center for Medium-range Weather Forecasts Re-Analysis Interim (ERA-Interim), and the Atmospheric Infrared Sounder (AIRS) instrument. These cross-comparisons serve as a performance guide for the GPS-RO observations with respect to other data sets by providing an independent measure of climate feedbacks and humidity short-term trends.