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China East Sea Coastal Wind Field observation by Synthetic Aperture Radar and Scatterometer

Xiaoming Li(1,2), Susanne Lehner(1), Johannes Schulz-Stellenfleth(1) and Ming-Xia HE(2)

(1) German Aerospace Center (DLR), Oberpfaffenhofen, 82234, Wessling, Germany
(2) Ocean University of China, Yushan Road 5, 266003 Qingdao, China


The present study was carried out in the framework of the ESA- NRSCC Dragon Program (ID 2566, Oceanography from Space). The Olympic Sailing Game 2008 will be held in Qingdao, China. The accurate wind field measurement is a key environment parameter for the sailing game. The traditional in-situ buoy data obtained are insufficient. The data time series are too short, and only defined at a single location. Furthermore the wind flow models usually used are difficult to accurately extrapolate the data from the point measurement over the entire area of interest. The active space borne sensors, like synthetic aperture radar (SAR) and scatterometer provide opportunity to measure the sea wind field with both large coverage and high spatial resolution. The software of SeaASAR for wind field retrieval from SAR image has been developed at the German Aerospace Center (DLR). Based on the software, nearly 20 SAR/ASAR images in the Qingdao sea area have been collected and are being processed and analyzed. In August 2007, the international Regatta sailing game was held in Qingdao as a test for 2008 Olympic game. The retrieved wind field from ASAR images in this month are compared with in-situ buoy data, and more over, compared with Laser Wind Radar data.

For the statistical analysis, Quickscat data in this area spawn from 1999 to 2007 have been collected and processed as well. Based on the SAR and Quickscat data, the wind field properties in the month of August in previous years in Qingdao sea area and the most proper date for the sailing game are given.

A wind field retrieval from SAR image case study is the observation of a storm surge in China East Sea (Bohai Sea and Yellow Sea) during 4th-5th, March 2007, which was the highest one in China since 1969. The collocated MERIS data is used as well for the wind field structure analysis. The retrieved wind field shows a good agreement with the German Weather Service (DWD) model results and the in-situ measurements.


Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry