地下水位下降对区域气候影响的虚拟试验

利用数值模拟方法,研究我国西北地区地下水位大幅度下降对干旱、半干旱气候变化的影响,并对地下水位变化和大气降水相互作用的反馈机制进行探讨.结果表明,地下水位大幅降落可以引发显著的气候效应,不仅引起降水的大幅度减少和近地面的增温,而且通过对土壤水状况的改变,引起了边界层结构和陆-气通量交换的变化.这些变化引起了局地对流层中低层大气环流的调整,进一步影响干旱气候.通过虚拟试验,反映了地下水变化对土壤水和大气降水等水分循环过程和干旱气候的巨大影响.

A Suppositional Experiment about the Impact of Groundwater Drawdownon Regional Climate Change in Northwest China

In this paper, the impacts of climate change caused actually by groundwater drawdown in arid and semiarid regions in northwest China are lucubrated using numerical simulation and a regional climatic model, and the feedback mechanism between groundwater drawdown and precipitation is analyzed. The results show that the serious groundwater drawdown in arid and semiarid regions in northwest China results in the distinctive climate effects, such as the sharp precipitation reduction, air temperature increase, drying of air near ground surface, change of boundary structure and ground-air flux exchange, and also affects strongly soil moisture regime. Thus, the low-atmospheric circulation in troposphere is changed, and the climate change in arid areas is affected. Although a suppositional experiment is carried out only, it reveals that groundwater drawdown affects seriously the soil moisture content, precipitation, water circle, climate change, etc. in arid areas. The results also show that it is necessary to consider the dynamic change of groundwater level and its impacts on precipitation,soil moisture content and surface water.