The effects of ice and precipitating clouds on Polarimetric Radio Occultation profiles

Polarimetric radio occultation (PRO) provides refractivity and phase difference between horizontal and vertical components of the radio occultation signals. This polarimetric phase difference occurs when the occultation ray paths cross an anisotropic medium like a layer of ice particles or non-spherical precipitating droplets. PRO from the PAZ satellite have been proven to capture these effects. PAZ GPS observations are used to correlate the phase difference with the precipitating water path and ice water path. The result presented is a data derived Look-Up Table (LUT) that is compared to the predicted LUT. The empirical LUT is used to infer a non-linear logistic map function that relates the phase difference to the ice/precipitating water path as a function of refractivity. We explored profiles that do not follow the logistic function to understand what physical processes could cause such anomalies. A cluster analysis based on the polarimetric phase difference and refractivity profiles is used to relate different type of profiles to occurrence of precipitation. The analysis presented correlates the different vertical cloud structures associated with different types of precipitation. These vertical structures of radio occultation refractivity profiles inform on the combination of temperature and water vapor at different altitudes inside the clouds, including thick convective clouds. Altitude changes in the polarimetric phase difference within these PRO profiles informs on the levels at which the thermodynamic conditions lead to precipitation or ice.