Retrieving Cloud Ice Water, Cloud Liquid Water, and other Cloud Parameters from GPS Radio Occultation and Satellite Microwave Imager/Sounder in Heavy

ABSTRACT: Cloud ice water content and cloud liquid water content strongly affect radiative transfer of solar energy to the atmosphere, and hence need to be taken into account in any modeling of the weather and climate. This proposal advances the poorly-known area of sensitivity of GPS RO to precipitation and clouds, and takes advantage of advances in signal measurement technology. The overall goal of the proposal is to determine the feasibility of using GPS Radio occultation to assist in retrievals of cloud properties in the presence of heavy precipitation. To achieve this goal we will: determine whether the expected magnitude of the differential GPS refractive delay due to heavy precipitation is significantly greater than reasonable detection limits in radio occultation measurements assess whether the thermodynamic and hydrometeor profiles from GPS RO can provide inputs to radiative transfer models in cloudy and heavy precipitation conditions that are improved relative to other alternatives for calibrating microwave retrieval techniques. assess the feasibility of adapting an airborne GPS RO system to test the detection limits in a realistic case study, because existing COSMIC data do not contain measurements at different polarizations to retrieve liquid water in the form of precipitation. BENEFIT: Retrieval of refractive delay due to precipitation and liquid water from GPS signals is a challenging new frontier. This proposal advances the poorly-known area of sensitivity of GPS RO to precipitation and clouds, and takes advantage of advances in signal measurement technology. The proposed effort will advance the GPS RO technique to enable retrievals of cloud ice water, cloud liquid water, and rain. The resulting cloud ice water content and cloud liquid water content could then be taken into account in modeling of the weather and climate. We anticipate that the GPS RO cloud ice and liquid water retrieval algorithms developed under this program will be implemented on ASTRA"s commercially available CASES dual frequency GPS receivers for spaceborne and airborne measurements.