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Altimeter dual-frequency observations of surface winds, waves, and rain rate in tropical cyclones

Yves Quilfen(1) , Bertrand Chapron(1) , and Jean Tournadre(1)

(1) IFREMER, BP 70 , 29280 - Plouzané, France

Abstract

Extreme weather events such as tropical cyclones are difficult to observe with conventional means. Satellite-based observations provide essential measurements of key parameters governing tropical cyclones. They are critical for short term forecasting. Radiometers onboard the DMSP satellite series, WindSat and TRMM , scatterometers onboard the ERS, ADEOS and QuikScat satellites, offer unprecedented synoptic observations of surface wind and atmospheric liquid water content, revealing the storm structures with good accuracy. However, satellite estimates don't provide direct measurements of geophysical parameters and can suffer from limitations linked to the sensors characteristics, such as the signal wavelength and polarization or the measurement incidence angle. For example, measurements at Ku-band are strongly affected by rain. Still, each observing system can offer specific information which can be combined with the others. In particular, we highlight the capabilities of dual- frequency altimeter to provide very high resolution measurements of rain rate, surface

wind speed and wave characteristics. A method is proposed to obtain continuous along track 5 km resolution measurements of these parameters in tropical cyclones. The results shows that dual-frequency altimeters can provide useful information to complement and validate the operational fields provided by the atmospheric numerical models and by the other observing systems.

 

Workshop poster

 

                 Last modified: 07.10.03