Decadal All-sky Terrestrial Precipitable Water Vapor Dataset from FengYun Microwave Imagers

Abstract Precipitable water vapor (PWV) is a key component of the Earth’s climate system, playing a vital role in weather, climate, and hydrological cycling. Passive microwave remote sensing offers a promising approach to measure all-sky PWV, though it remains challenging over land. Building on our previous development of a machine learning algorithm, we have created a global terrestrial PWV dataset using measurements from the MicroWave Radiation Imager (MWRI) aboard three FY-3 satellite series (FY-3B, FY-3C and FY-3D). The dataset spans from 2012 to 2020 at a spatial resolution of 0.25° × 0.25°. It was validated against SuomiNet GPS and IGRA2 (Integrated Global Radiosonde Archive Version 2) PWV products, achieving root-mean-square errors (RMSEs) of 4.47 and 3.89 mm, respectively, with RMSE values ranging from 2.90 to 5.49 mm across diverse surface conditions. As an all-weather PWV product with high-precision, the MWRI PWV dataset addresses gaps in global passive microwave-based terrestrial PWV observations, offering significant value for atmospheric research, climate modeling, hydrological studies, and beyond.