Advances in the use of Global Navigation Satellite System polarimetric radio occultation measurements for NWP and weather applications

Conventional radio occultations (RO) track the phase delay induced by water vapor and air density gradients in Global Navigation Satellite System (GNSS) signals as they propagate through the Earth’s atmosphere. Standard RO products such as bending angle profiles from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC-2), the EUMETSAT Metop satellites and numerous other publicly and commercially available RO products are routinely assimilated into operational Numerical Weather Prediction (NWP) forecast models. The positive impact to forecasts of temperature and winds when RO data are included in the suite of observations ingested into data assimilation (DA) systems is well documented. Polarimetric RO (PRO) enhances standard RO by receiving the GNSS signals with a dual-polarization RO receiver. In addition to the capabilities of the conventional RO, PRO can provide an indication of precipitation 1 at each vertical level, offering a potential to advance the assimilation of satellite data in precipitating conditions. PRO observations provide unique diagnostics and observations for investigating the thermodynamic environment in and near precipitation, and assumptions underlying parameterizations used by operational NWP forecast models.