The analysis of water vapor budget and its future change in the Yellow-Huai-Hai region of China

This study aims to analyze the atmospheric water vapor budget changes in the Yellow-Huai-Hai River basin and explore the possible relationship between water vapor budget and precipitation. The Fifth Phase of the Coupled Model Intercomparison Project is used to assess the future change of water vapor in the region. Corrected general circulation model outputs are evaluated, and multimodel ensemble is used to project the future atmospheric water vapor changes. Results show the following: (1) Water vapor in wet summer, which is transported from Bengal Bay and west Pacific Ocean and accounts for the largest part of annual transport, has similar distribution with precipitation in the study area; (2) Strong evidences indicate significant relationships between the precipitation and water vapor in humid area and semihumid area, but poor relationship in semiarid area; (3) The future climate of the region is projected to be wetter but has a “dry belt” located in the Hai River basin, the north of the Huai River basin and the southeast of the Yellow River basin during 2020s, which will reduce rapidly afterward; (4) Summer water vapor changes depend mainly on the meridional transport. The changes under RCP4.5 scenario are smaller than that under RCP8.5 and the increases are more significantly in 2080s under both scenarios. The water vapor has a larger increase in the Huai River basin than that in the other two basins. Future water vapor changes will likely lead to exacerbated problems caused by the uneven distribution of precipitation and produce serious challenges to water resource management in agriculture, industry and the environment.