Variation characteristics and influential factors of extreme climate in Sichuan Province from 1961 to 2022

Abstract

[Objective] The characteristics of extreme climate change in Sichuan Province under the background of global climate change were studied, with the objective of mitigating the adverse impact on regional social economy, agricultural production, ecological environment and other aspects. [Methods] Based on the meteorological observation datasets including daily precipitation, maximum temperature and minimum temperature at 40 stations in Sichuan Province, 20 different extreme climate indices were calculated. Linear trend analysis, Local weighted regression analysis, Mann-kendall trend test, Pearson correlation analysis and ARCGIS software were used to analyzed the temporal and spatial variations of climate extremes in the mountain area of the eastern Sichuan Basin, the west Sichuan alpine plateau area and the southwest Sichuan mountain area, and the influential factors were discussed. [Results] In Sichuan Province, the extreme temperature indices were characterized by increasing trend, which were significant. The extreme precipitation indices were characterized by wetting, but the trends were not significant. [Conclusion] (1) Extreme warm(cold) events increased(decreased) in Sichuan province from 1961 to 2022, and showed the characteristics of “the rise of low temperature was more obvious than that of high temperature, the warming at night was higher than that of daytime, and the number of warm days were higher than that of cold days”. Spatially, the extreme temperature indices showed increasing trend in all regions of Sichuan province, and the increasing trend was more significant in high altitude areas such as the west Sichuan alpine plateau area and the southwest Sichuan mountain area.(2) In Sichuan province, the precipitation and the concentration of precipitation increased. Spatially, the west Sichuan alpine plateau area had a tendency of wetting, the mountain area of the eastern Sichuan Basin and the southwest Sichuan mountain area had a tendency of drying. The extreme precipitation indices showed a change characteristic of “west wetting and east drying”.(3) Most of the extreme climate indices were significantly correlated with annual mean temperature, annual precipitation, longitude and altitude, while the correlation with latitude was low. The extreme climate change in Sichuan Province mainly influenced by the Atlantic multidecadal oscillation(AMO) and the AMO had the most significant influence on the extreme climate. The analysis of the changing characteristics of extreme climate indices under the background of global warming is of great significance for flood control and drought relief in Sichuan Province.

Keywords

Sichuan Province / extreme temperature / extreme precipitation / changing trends / influential factors / climate change / spatiotemporal distribution