Trends of precipitation and characteristics of wetness-dryness encountering in the water source and receiving areas of the west route of the South-to-North Water Transfer Project
Based on the daily precipitation data from 274 national meteorological stations in the west route of the South-to-North Water Transfer Project area from 1961 to 2022,the spatiotemporal distribution characteristics of annual and seasonal precipitation in the water source and receiving areas were analyzed,as well as the characteristics of the encounter between dryness and wetness in the two areas.The results show that in the past 62 years,the precipitation in the water source area of the west route of the South-to-North Water Transfer Project showed an increasing trend,while the trend of precipitation in the water receiving area was not significant.The seasonal precipitation of summer and winter in both water source area and receiving area increased.The precipitation of spring and autumn in water source area increased while that in water receiving area decreased.The frequency of dryness in water source area was lower than that in water receiving area in spring,summer,and autumn.The frequency of dryness in water source area showed a decreasing trend,while the frequency of wetness showed an increasing trend.The asynchronous frequency of annual and seasonal precipitation in the water source area and receiving area was above 60%,which was much higher than the synchronous frequency.The five types of dryness-wetness encountering favorable for water transfer occurred at a frequency of over 50%in spring,summer,and autumn.In general,the precipitation in water source and receiving areas of the west route of the South-to-North Water Transfer Project had a strong compensatory effect,and the frequency of dryness-wetness encountering favorable for water transfer increased after 1971,ensuring the possibility of water supply.However,the frequency of continuous dryness years in water source area was high.Therefore,it is necessary to consider climate changes of precipitation in water source and receiving areas in the planning,design,and operation scheduling of the west route of the South-to-North Water Transfer Project.
PrecipitationWetness-dryness encounteringThe west route of the South-to-North Water Transfer ProjectWater source areaWater receiving area