Retrieval and Validation of Atmospheric Vertical Temperature Profile from Satellite's Microwave Sounding

摘要

The paper is intended to retrieve atmospheric temperatures from AMSU soundings by a combined physical-statistical scheme and a regression model is established on weighting functions of AMSU channels 3～14 calculated by the Liebe model (Liebe 1981,1985) and the normalized weighting functions are employed as its constraints, and the optimal solution is obtained by appropriately adjusting the constraints. Results show that when nadir AMSU samples are adopted, the constrained regression algorithm yields higher retrieval accuracy with the root-mean-square error of 0.4 K (1.0 K) below (at and above) 100 hPa. By the same algorithm a limb adjustment is made of off-nadir fields of view. For atmospheric sounding channels 4～14 (frequencies of 52.8～57.29 GHz) the maximum deviation is thereby decreased to ± 0.9 K from -15～5 K. Retrieved temperatures are utilized to investigate the warm-core structures of 15 tropical cyclones making landfall in China mainland during 2002 and 2003, indicating that retrievals have ability to reveal clearly the structure and better correlativity of the temperature anomaly to the surface central wind speeds and the sea-level central pressures of cyclones. As a reference, therefore, the correlation is of utility to forecasting.