Shu-Ya Chen
Global Atmospheric Observation and Data Applications Research Center, NCU
The Global Navigation Satellite System radio occultation (GNSS RO) technique provides high-quality atmospheric vertical profiles that are widely used for weather analysis and forecasting. RO also plays a critical role in data assimilation (DA) systems, particularly over oceans where conventional observations are sparse. GNSS RO data, such as those from FORMOSAT-7/COSMIC-2, penetrate deeply into the lower troposphere, delivering essential mid- to lower-tropospheric atmospheric information for tropical cyclogenesis prediction. Our research demonstrates that assimilating RO can further improve the success rate of tropical cyclogenesis simulations, mainly by increasing mid-tropospheric moisture through RO DA and thus providing initial conditions more favorable for capturing genesis. Even when satellite radiance data are assimilated, the positive impact of RO remains evident. In recent years, the polarimetric RO (PRO) technique has been developed to measure the differential polarimetric phase shift, which is sensitive to heavy precipitation. At the same time, traditional RO products can be retrieved concurrently. This unique capability shows strong potential for evaluating microphysics parameterizations in numerical models, highlighting new opportunities for model improvement and process diagnostics.
