Spatiotemporal variation of precipitation and its environmental response in the Chongqing section of the upper reaches of the Yangtze River in the last 20 years
Background,aim,and scope Under the background of global warming,the distribution of precipitation in different regions of China is complex,therefore,it is difficult to forecast meteorological disasters,which cause tremendous socio-economic and ecological losses,based on historical weather data.Furthermore,determining the distribution of precipitation in an area with complex terrain is problematic.To meet the urgent needs of meteorological disaster prevention and reduction and management of water resources,this study analyzes the temporal variation trend and spatial differentiation characteristics of precipitation in Chongqing from the aspects of variation trend,mutation points,and periodicity through data processing.Materials and methods Based on the monthly precipitation data of 34 meteorological stations provided by the Chongqing Climate Center for the period from 2000 to 2019,the four seasons were divided according to the general seasonal division principle in Chongqing.Using linear regression,the M-K nonparametric test,the Morlet small wave function,and Kriging interpolation,the precipitation data of Chongqing since 2000 were sorted and analyzed.Results From 2000 to 2019,Chongqing's annual precipitation ranged from 875.6 mm to 1348.2 mm.The temporal analysis showed that there was an obvious increasing trend in spring and autumn and that March was the most significant.The annual and seasonal precipitation fluctuated the most in the 14 a time scale cycle,which was the first main cycle.The spatial distribution was low in the west and high in the east.Discussion In the last 20 years,the precipitation in western Chongqing and the Yangtze River Valley has been relatively low,which is mainly affected by the topography of Chongqing.Autumn precipitation increased significantly in western Chongqing and northeast Chongqing.The overall precipitation trend shifted from a decline to an increase in 2013.Although summer precipitation accounted for more than that received for the entire year,there was a decreasing trend in precipitation.The increasing trend of precipitation in spring and autumn was obvious.Specifically,the increasing trend reached a significance level of 0.05 in autumn.Winter precipitation was the least,and the trend was slightly lower.Conclusions The overall variation of precipitation in Chongqing was characterized by seasonal variations,uneven spatial distribution,and significant local differences.The decisive factor was monsoon circulation,and the influencing factors included temperature,topographic and geomorphic features,and the Three Gorges Reservoir.Recommendations and perspectives The spatiotemporal variations of precipitation in Chongqing are summarized and discussed in depth.The research results can provide a theoretical basis for local drought and flood disaster prevention,exploitation and utilization of water resources,and sustainable economic and social development.
upper reaches of the Yangtze Riverspatiotemporal variations of precipitationcomplex terrain areaChongqing