Geophysical parameters retrieving algorithm of AMSR

Space-borne microwave radiometer plays an important role in retrieving geophysical parameters of the global ocean surface.The Advanced Microwave Scanning Radiometer(AMSR-E),launched on May 4,2002 aboard NASA's Aqua spacecraft,is a passive microwave sensor that precisely measures microwave emission from the earth surface and atmosphere with multiple frequency bands.AMSR-E can measure a series of oceanic parameters,such as atmospheric water vapor,cloud liquid water,precipitation,sea surface wind,sea surface temperature,sea ice,snow cover,and soil moisture.In this paper,an ocean surface microwave emission/scattering algorithm and an atmospheric radiation algorithm are developed for retrieving geophysical parameters from AMSR-E brightness temperatures.Sea surface wind,sea surface temperature,water vapor,and cloud liquid water of global ocean are retrieved.The results are validated by NCEP reanalysis data,as well as TAO buoy data on the Pacific Ocean.The retrievals are also compared with those from Wentz2000 algorithms for evaluating accuracy of the algo-rithm.It is found that there are excellent correlations between the in situ parameters and those retrieved from either statistical algorithms or physical algorithms.It is also found that there exits system biases in all retrieved parameters which can be well corrected by a linear equation.The results compared with NCEP's are different from those with TAO's,which may results from the uncertainties in NCEP data.The final RMS error of sea surface wind,sea surface temperature are 1.21m/s,0.73K,respec-tively,comparing with TAO 's.