Daily Variations of Global Tropical Ocean Surface Wind Speed Based on the CYGNSS Data

Daily variations, including both diurnal and semidiurnal cycles, are fundamental modes of variability in the global climate system. Accurate and reliable observations of the daily variations of ocean surface winds are critical for global weather and climate predictions. However, due to the limited spatial and temporal coverages of the current in-situ and satellite observations, the daily variations of global tropical ocean surface winds have not been well characterized nor well understood. The new surface wind speed data provided by the NASA Cyclone Global Navigation Satellite System (CYGNSS) mission have high temporal (~3-hourly) and spatial (25-km) resolutions under all precipitating conditions. Here, we present our results on the daily variations of tropical ocean surface winds based on CYGNSS data. We will discuss the relative importance of diurnal cycle and semidiurnal cycle and the comparison between the CYGNSS results and in-situ buoy results.