Study On Precipitation Characteristics And Risks Of The Main Water Resource Areas Of The Belt And Road

Precipitation is the basic link that constitutes the Earth's water cycle,and it is also the main source of surface water,playing a very important role in human activities and economic development.Extreme precipitation,as an extreme situation in the process of precipitation,can easily lead to natural disaster such as floods and droughts,causing enormous economic property loss and life safety threats to human society,especially in recent years,with the constant changes in the global climate,the frequency,intensity of extreme precipitation and harm to human society is also increasing.The “Belt and Road” is a national-level top cooperation initiative proposed by China in 2013.Due to the wide range of areas along the “Belt and Road”,the precipitation situation is complex and extreme precipitation is frequent,it is necessary and urgent to study the temporal and spatial variation characteristics of precipitation and extreme precipitation in the “Belt and Road” area,and to analyze the extreme precipitation and risks that may occur in the area.The author's research team delineated the main water resources area of the “Belt and Road” according to the national policy,Official documents and navigation route,and this study takes it as the research object.The temporal and spatial variation and distribution characteristics of precipitation in the study area were systematically analyzed from different time scales in year,month and season;Selecting the core extreme precipitation index of the World Meteorological Organization to analyze the temporal and spatial variation characteristics of extreme precipitation;Using the generalized extreme value distribution to fit the extreme precipitation indicators in different return periods,characterize the extreme precipitation hazard under different return period scenarios,combined with the regional vulnerability characterized by land use data and the nighttime lighting data,the risk of extreme precipitation is evaluated.The main research contents include the following aspects:(1)Temporal and spatial variation characteristics of precipitation of the main water resources area of the “Belt and Road” from different time scales in year,month and season.Based on the CRU global grid precipitation data,the spatial distribution of precipitation at the annual,seasonal and monthly scales of the main water resources area of the “Belt and Road” is analyzed,and the trends and mutation characteristics of precipitation at different time scales area also analyzed by M-K test method.The method of concentration and concentration period is used to analyze the characteristics of the annual distribution of precipitation in the study area.(2)Temporal and spatial variation characteristics of extreme precipitation in the main water resources area of the “Belt and Road”.Based on the daily observation data of the global precipitation site issued by the National Oceanic and Atmospheric Administration,6 kinds of extreme precipitation indicators(SDII,PRCPTOT,RX5 DAY,R95P,CDD,CWD)are selected for calculation to analyze the temporal and spatial variation of extreme precipitation in the study area.(3)Study on the extreme precipitation hazard of the main water resources area of the “Belt and Road”.Using the generalized extreme value distribution function to fit the extreme precipitation indexes of each first-level subzone of the main water resources area of the “Belt and Road”,and verify the applicability of the generalized extreme value distribution to different extreme precipitation indicators in different regions;Using the generalized extreme value distribution to fit the extreme precipitation index values in the four typical return period scenarios of 5,10,50,and 100 years to characterize the extreme precipitation hazard under different return period scenarios.(4)Extreme precipitation risk assessment of the main water resources area of the “Belt and Road”.Using extreme precipitation indicators under different return scenarios to represent the extreme precipitation hazard of the “Belt and Road”;The nighttime light index and land use data are used to characterize the vulnerability of the region after the disaster;Based on the extreme precipitation hazard and regional vulnerability,the risk of extreme precipitation under different return periods is evaluated.