植被变化对中国区域气候影响的数值模拟研究

用高分辨率区域气候模式(RegCM-NCC)模拟了中国区域植被发生改变后引起的局地或区域气候变化。结果表明:大范围区域植被变化对区域降水、温度的影响非常显著,内蒙古地区土地荒漠化可导致中国北方大部分地区降水减少,尤其加剧了华北、西北地区的干旱,西北地区绿化有利于黄河流域降水增加,而长江流域和江南地区降水却有不同程度的减少,因此可在一定程度上减少这里的洪涝灾害;气温的变化比降水更显著,植被退化使当地气温明显升高,使中、低层大气变得干燥,近地层风速加大,而植树造林却使当地及周围地区冬偏暖、夏偏凉,大气变得湿润,近地层风速减小,有利于在一定程度上减少沙尘暴的发生。另外,植被变化对东亚冬、夏季风强度也有一定程度的影响,从而影响到中国东部地区降水的分布和冬季低温、冷害事件发生的强度。

A NUMERICAL SIMULATION STUDY OF THE IMPACTS OF VEGETATIONCHANGES ON REGIONAL CLIMATE IN CHINA

By using the regional climate model(NCC/RegCM),two modeling experiments were undertaken to investigate the regional climate change by changed vegetation in China,and results indicate that vegetation changes in large regions have notable effect on regional rainfall and temperature: desertification in Inner Mongolia results in rainfall decreasing in many regions,especially in north China and northwest China.On the contrary,reforestation in northwest China leads to rainfall increasing in Yellow River basins,but rainfall decreasing to different degree over Yangtze River basins and south China in summer,and hence,conduce to less flood occurrence over there.The effects to temperature is more significant,with temperature remarkable increasing over the desertification region,as well as wind on lower layer enhancing, as a result,the local climate becoming drier and unfavorable for vegetation regrowing.But in the reforestation region,local air temperature become warmer in winter and cooler in summer,with more moisture supplying to atmosphere and lower wind decreasing,thus may be reduce dust storm weather in some degree.On the other hand,vegetation changes also have obviously effects on the intensity of East Asian summer and winter monsoon,so tends to influence the rainfall distribution over East China and the occurrence of low temperature damages in winter.