Optimizing the Utilization of CYGNSS Wind Observations for Numerical Prediction of Tropical Cyclones

For the analysis and forecasting of tropical cyclones (TCs), the main benefits of data from the CYGNSS constellation of satellites are the increased revisit frequency compared with polar-orbiting satellites and the ability to provide ocean surface wind observations through convective precipitation. Consequently, CYGNSS delivers an improved capability to observe the structure and evolution of ocean surface winds in and around tropical cyclones. This study quantifies the impact of assimilating the most recent version of CYGNSS retrieved wind speed on 6-hourly analyses and 5-day forecasts of weak TCs, using a version of NOAA’s operational regional model. We focus on TCs whose forecast was initialized when the TC was a tropical storm or depression. The analysis includes impacts of improved surface wind initialization on the initial ocean state and nearsurface ocean evolution under the coupled TC model, as well as impacts on skill of storm forecasts for intensity and surface wind structure. This paper will present the methodology and results of the observing system experiments (OSEs).