Significant increase in humidity since 2003 in Qinghai Province, China: evidence from annual and seasonal precipitation.

Abstract

Recently, extreme climate events have become more frequent under global warming, resulting in increasingly severe disaster losses. Essentially, the variability in precipitation is more uncertain compared to temperature. In this study, monthly precipitation data from 30 stations in Qinghai Province from 1960 to 2020 were selected to investigate the spatial-temporal variations in precipitation via linear tendency estimation, variability, cumulative anomaly, Mann-Kendall test, and spatial interpolation methods. The conclusions are as follows. (1) The annual and four seasons' average precipitation in Qinghai Province showed an increasing trend over the last 61 years, and the enhancement of summer and spring average precipitation contributed more to the annual. (2) There are increasing trends from northwest to southeast in the annual and seasonal mean precipitation, whose distributions are jointly controlled by the East Asian summer monsoon (EASM), the westerlies, and geomorphological features. (3) It is reasonable to conclude that the annual and four seasons' average precipitation has increased significantly since 2003 by integrating the results of variability, cumulative anomaly, and Mann-Kendall test. In other words, the significant intensification of humidity in Qinghai since 2003 is closely related to the ongoing intensification of the EASM and the westerly wind circulation, with the latter contributing considerably. These findings confirm the view of warming and humidification in northwest China and provide a reliable time point for discussing warming and humidification in northwest China.