土壤含水量改变对气候影响的数值模拟

 中国南北方水土资源配置不合理,南方水多耕地少,北方水少耕地多。南水北调工程通过跨流域的水资源合理配置,大大缓解北方水资源严重短缺问题。本文用两层嵌套的中尺度气象模式MM5及其耦合的陆面过程模式,研究调水对局地气象环境的影响。研究表明,实施南水北调后,春季和夏季北方地区土壤含水量增加、累积降水量增加,地表温度降低。夏季的土壤含水量、地表温度、累积降水量的变化幅度明显大于春季。另外干燥的土壤环境条件,对气象环境的改变更明显。春季和夏季土壤含水量变化的区域、地表温度的降低的地区都不只局限于南水北调受水区,而是散布到周边地区。另外还可以看出,在土壤含水量未改变的地区有明显的降雨量增加,最大降雨量增加区域与土壤水份的变化中心区域不重合。

Numerical Simulation of Soil Moisture Variation on Climate

Water resource appears the serious region difference between southern and northern part of China. The northern part belongs to the dry region which water is hard up; however, the supply exceeds demand that is the character of water resources in the southern part. Along with the economical development and the climatic fluctuation, the contradiction between the supply and demand for water resource in the northern part is gradually becoming serious, since 1980s. The trend of climatic fluctuation is represented by the decreasing precipitation and increasing temperature. The economical loss and the environmental degeneration become more obvious than ever before. The drought affects people's life and work seriously. Water transportation from south part to north part of China is a valid measure to resolve this problem. Through water transportation from south to north part of China, the contradiction involving water shortage could be solved. It could improve environment and accelerate the speed of social development. The change of soil moisture that influences on the local environment of meteorology is researched. The mode of MM5 is used to simulate, and the Oregon State University Land Surface Model(OSULSM)is selected as the land surface mode. It could be found that for the different seasons, with same amount of the initial soil moisture increasing, there is different range of increasing on the seasonal average soil moisture, and it is corresponding with the different range of changing on the precipitation and the ground temperature. For different seasons, with the same variety of soil moisture, the change is larger in the summer than that in the spring in terms of precipitation and the ground temperature.