Evaluation of Precipitable Water from FY-4A Based on GNSS Retrieval
Abstract：To effectively evaluate the quality of the water vapor product of FY-4A, the 2022 water vapor product of FY-4A was evaluated based on the precipitable water retrieved by GNSS and the ground station observed precipitation data. The results show that when FY-4A and GNSS simultaneously retrieve the water vapor product, the fitting degree is best in October, with R2 exceeding 0.93; April and November are next; December is the worst, with R2 only at 0.72. When the precipitable water (PWV) retrieved by GNSS is less than 30 mm, the fitting degree is slightly lower; when PWV is greater than 30 mm, the fitting degree R2 exceeds 0.99. The water vapor product of FY-4A is comparable to the results retrieved by GNSS, showing good credibility and can be used for climate assessment and data assimilation in numerical weather forecasting.
Keywords：Fengyun-4A satelliteGlobal Navigation Satellite SystemWater vapor productFitting degree
Publication Date：2025-10-20
Online Publishing Date：2025-10-30(First online date of this platform, not the publication date of the document)
Pages：4( 77-80 )