Paper Info
Title
Calibrating the Haiyang-2A Calibration Microwave Radiometer When the 18.7-GHz Band Fails
Abstract
The wet tropospheric correction (WTC) retrieved from the onboard calibration microwave radiometer (CMR) of Haiyang-2A (HY-2A) is critical in monitoring the global sea level. However, the CMR WTC became significantly biased from June 2017 due to the failure of the 18.7-GHz band, which caused massive errors in the sea surface height (SSH) measurements. We investigate the accuracy of the CMR WTC derived from the two remaining bands to address this problem. A comprehensive evaluation using multisource data demonstrates that the dual-band + backscattering coefficient (BC) algorithm achieves comparable accuracy to the three-band algorithm, and it does not suffer from any large errors when the equipment works well. Hence, we calibrated the HY-2A CMR data with the dual-band + BC algorithm when the 18.7-GHz band failed, and the accuracy of the CMR WTC is improved from 2.34 to 1.39 cm compared with European Center for Medium-Range Weather Forecasts (ECMWF) ERA5 data. In addition, the SSH measurements are improved significantly by a maximum of 2 cm in mean value using the dual-band + BC WTC during the failure period of HY-2A CMR. Compared with Jason-3 SSH measurements, the HY-2A with dual-band + BC shows a slightly larger difference than HY-2A with three-band by 0.1 cm in rms. This method prolongs the operational lifetime of the HY-2A CMR and could be used in the reprocessing of HY-2A observations.
Year
DOI
Venue
2022
10.1109/TGRS.2021.3073278
IEEE Transactions on Geoscience and Remote Sensing
Keywords
DocType
Volume
18.7-GHz band,backscattering coefficients (BCs),calibration microwave radiometer (CMR),dual-band,Global Navigation Satellite System (GNSS),Haiyang-2A (HY-2A)
Journal
60
ISSN
Citations 
PageRank 
0196-2892
0
0.34
References 
Authors
0
7
Name
Order
Citations
PageRank
Zhilu Wu100.34
Yanxiong Liu224.09
Yang Liu300.34
Jungang Wang400.34
Xiufeng He51612.88
Wenxue Xu602.37
Maorong Ge72919.02