Interpretation of the Precipitation Structure Contained in Polarimetric Radio Occultation Profiles Using Passive Microwave Satellite Observations

Observationally, a major source of uncertainty in evaluation of climate models arises from the difficulty in obtaining globally distributed, fine scale profiles of temperature, pressure and water vapor, that probe through convective precipitating clouds, from the boundary layer to the upper levels of the free troposphere. In this manuscript, a two-year analysis of data from the Radio Occultations through Heavy Precipitation (ROHP) polarimetric RO demonstration mission onboard the Spanish PAZ spacecraft is presented. ROHP measures the difference in the differential propagation phase delay (Δ𝜙) between two orthogonal polarization receive states that is induced from the presence of non-spherically shaped hydrometeors along the Global Navigation Satellite System (GNSS) propagation path, complementing the standard RO thermodynamicprofile. Since Df is a net path-accumulated depolarization and does not resolve the precipitationstructure along the propagation path, orbital coincidences between ROHP and the GlobalPrecipitation Measurement (GPM) constellation passive MW radiometers are identified toprovides three-dimensional precipitation context to the RO thermodynamic profile. Passive MWderived precipitation profiles are used to simulate the Δ𝜙 along the ROHP propagation paths.Comparison between the simulated and observed Δ𝜙 are indicative of the ability of ROHP to detectthreshold levels of ray path-averaged condensed water content, as well as to suggest possibleinferences on the average ice phase hydrometeor non-sphericity. The use of the polarimetric RO vertical structure is demonstrated as a means to condition the lower tropospheric humidity by the top-most height of the associated convective cloud structure.