三峡下垫面变化对区域气候效应的影响研究

The impact of the land use change associated with the Three Gorges Dam on regional climate change

利用中尺度数值天气预报模式（WRF），通过控制试验与改变三峡库区水体结构的理想试验，分析了三峡库区蓄水后可能引起的区域气候效应．研究结果标明：针对三峡库区气候特征的再现能力分析发现逐月模拟实验优于逐日模拟实验；三峡大坝的水体扩展引起了库区区域气候的较弱变化，平均气温与平均风速的变化较小，仅在狭窄的三峡水道上出现了弱的气温升高与风速增大的现象，变化幅度分别为0．5℃～1．5℃、0．1～1m／s；三峡库区水体面积扩大后引起了库区北部部分地区的降水增加，这主要是由于下垫面的变化与局地特殊地形相耦引起了水汽与风场的变化，从而影响了降水量的变化．三峡工程引起的气候变化主要表现在近地层，越往高层影响越小，对850hPa及以上高度层几乎没有影响．

The impact of the Three Gorges Dam （TGD） on regional climate change is examined trough comparison between the two simulations of control and land use change, using the Weather Research and Forcast （WRF） model. According to the ability of reappearing the cliamte change on the Three Gorges resevoir area, the results show that the simulation with monthly continuous integration is superior to that with dayly continuous integration. The analysis indicates the climatic effect of the land use change associated with the TGD construction is weak on the regional scale. The surface temperature of the TGD region is increased, which range is 0.5 ℃ to 1.5 ℃, and there is almost no change on any other areas. Similar to the temperature, the wind speed of near surface is only changed on the area of TGD, which increased from 0.1 to 1 m/s. The precipitation in the north of the TGD is increased, which may he owing to the interaction between the iand use change and the complex topography, these efforts might change in the vapour and wind patterns, which can have major effects on precipitation. The results also indicate the climatic effect of the TGD is mainly refelect on the near-surface level, and away from the ground, the effect decreases quickly with height. There is almost no effect exceeding the 850 hPa pressure level above the land.