Warmer and wetter climate induced by the continual increase in atmospheric temperature and precipitable water vapor over the arid and semi–arid regions of Northwest China

Abstract

Study region: arid and semi–arid regions of Northwest China Study focus: Precipitable water vapor (PW) is the medium for energy and water exchange, and supplies moisture for precipitation. Based on meteorological data and PW data from observation and six reanalysis products, the climate shift in the arid and semi–arid regions of Northwest China (ASRNC) during 1980–2018 have been explored by applying the reference PW scaling and conversion efficiency of precipitation. New hydrological insights for the region: The PW of reanalysis data sets was overestimated in spring, while was underestimated in summer, autumn, and winter. However, the spatial distribution of simulated PW was more consistent with the topography of the ASRNC. From 1980–2018, in the context of overall regional warming, the PW was more likely to present significant increasing trends over the regions with high and increasing PW scaling. In general, the PW increased from 1980 to 2000, the fluctuating upward trend intensified thereafter. Meanwhile, the increasing rates of simulated PW were remarkably underestimated during 2000–2018. The precipitation in the ASRNC was greatly influenced by the precipitation conversion efficiency, especially in spring and autumn. Generally, the wet tendency was identified in the western and central regions because of the increase in PW and precipitation conversion efficiency from 1980 to 2018.

Keywords

• Arid and semi–arid regions of China
• Precipitable water vapor
• PW scaling
• Precipitation conversion efficiency
• Climatic shift