Effects of the Wave State on TOPEX/Poseidon Altimeter for Retrieving Winds

The effects of the wave state on the altimeter wind speed retrieval are investigated based on the observations in the Gulf of Mexico. The comparison between measurements from the altimeter and buoys shows that the wave state has significant effects on the altimeter wind speed retrieval. After considering the effects of the wave state, the altimeter winds speed is retrieved more accurately with a new wind wave spectrum model. Compared with the wind speed retrieval algorithm in the operational use for TOPEX/Poseidon altimeter, after the effects of the wind state are included in the analytical algorithm, the root-mean-square difference and the averaged bias between retrieved altimeter wind speeds and buoy observations are 30 % and 83 % less, respectively. The wave age factor which denotes the wave state can be calculated from altimeter measured Hs and U10 ( from algorithm in the operational use for TOPEX/Poseidon altimeter ). Thus, the analytical algorithm proposed in this study has a comprehensive applicability.