Untangling rain structure from polarimetric GNSS radio occultation observables: A 2D tomographic approach

Abstract

A new rain measurement concept will be tested aboard the Low Earth Orbiter (LEO) PAZ, (launch planned for 2016). It aims to detect and quantify intense rain using the polarimetric phase-shift induced by rain droplets along GNSS radio occultation’s rays. Due to the integral nature of the measurement, rain intensity and extension are difficult to untangle. The work presented here applies tomographic techniques to reconstruct the precipitation structure from the integrated measurement. The technique shows the capability of retrieving simple structures using only the information self contained in the radio occultation observables, while for more complex structures external information would be needed in order to refine the retrievals.