Decadal all-sky terrestrial precipitable water vapor dataset from Fengyun microwave imagers

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 (ML) 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 Integrated Global Radiosonde Archive Version 2 (IGRA2) PWV products, achieving root mean square errors (RMSE) of 4.47 mm 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 modelling, hydrological studies, and beyond.