Publications

Ji, Dabin; Shi, Jiancheng (2014). Water Vapor Retrieval Over Cloud Cover Area on Land Using AMSR-E and MODIS. IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, 7(7), 3105-3116.

Abstract
This study mainly discusses atmospheric water vapor retrieval over cloud cover area on land with the help of a newly developed surface emissivity parameter estimation method in microwave bands. In the retrieval method, the atmospheric water vapor sensitivity parameter-ratio of brightness temperature polarization difference at frequencies 18.7 and 23.8 GHz (Delta Tb-18.7/Delta Tb-23.8)-is used to retrieve water vapor, and the surface emissivity parameter-ratio of surface emissivity polarization difference at frequencies 18.7 and 23.8 GHz (Delta epsilon(18.7)/Delta epsilon(23.8)) that corresponds to Delta Tb-18.7/Delta Tb-23.8-is a key parameter that affects the final precision of retrieved atmosphere water vapor. In order to estimate Delta epsilon(18.7)/Delta epsilon(23.8) in cloudy condition, we first estimated the value of Delta epsilon(18.7)/Delta epsilon(23.8) in clear condition using Advanced Microwave Scanning Radiometer for EOS (AMSR-E) brightness temperature and related MODIS atmospheric products. At the same time, it was found that gradient information derived separately from and Delta Tb-18.7/Delta Tb-23.8 and Delta epsilon(18.7)/Delta epsilon(23.8) has very good correlation with each other. Based on this good correlation, the Delta epsilon(18.7)/Delta epsilon(23.8) in cloudy condition was estimated using corresponding Delta Tb-18.7/Delta Tb-23.8 and adjacent 8 days Delta epsilon(18.7)/Delta epsilon(23.8) in clear condition. With the estimated Delta epsilon(18.7)/Delta epsilon(23.8), we retrieved atmospheric column water vapor using lookup table method in cloudy condition over land. As a validation source data, the SuomiNet GPS-retrieved precipitable water (PW) vapor is used to validate the retrieved water vapor in this study. According to validation, the correlation coefficient of the two is 0.94 and the root-mean-square-error (RMSE) is 4.85 mm. It is a great improvement in water vapor retrieval using microwave in cloud cover area on land.

DOI:
10.1109/JSTARS.2014.2298979

ISSN:
1939-1404