Comprehensive Evaluation and Comparison of AIRS, VASS, and VIRR Water Vapor Products Over Antarctica

The detection capability of the water vapor mixing ratio (q) and total precipitable water vapor (PWV) products of the Atmospheric Infrared Sounder (AIRS), the Atmospheric Vertical Sounder System (VASS), and Visible and Infrared Radiometer (VIRR) in Antarctica is unclear due to the harsh environment and the scarcity of ground-based stations. This study compares these products with data from nine radiosonde stations and 10 Global Navigation Satellite Systems Stations and evaluates them using the CCHZ-DISO method. In the low atmosphere, the average wet bias of about 22% of VASS q is significantly greater than that of AIRS q (<15%), and the dry bias of AIRS is gradually corrected with increasing cloudiness, but the trend of exacerbated wet bias at 700 hPa requires attention. Meanwhile, VASS should optimize the inversion principle in the presence of clouds and refine the utilization weights of the channels heavily influenced by clouds under different cloud fraction conditions. Furthermore, when the atmospheric pressure is less than 500 hPa, VASS q exhibits a significant wet bias, and these data should be used cautiously. Both AIRS and VIRR detect PWV well in coastal areas, but VIRR PWV is significantly overestimated in the dry ice sheet plateau region. The CCHZ-DISO value intuitively reveals that AIRS outperforms VASS and VIRR in both q and PWV detection. The findings of this study contribute to a more comprehensive understanding of the detection capability of the above satellite water vapor products to promote the wider application of satellite data in the Antarctic region.