黄土高原植被生长期旱涝对全球气候变化响应

Response of Droughts or Waterloggings in the Loess Plateau in China to Global Climate Change

为了揭示黄土高原植被生长期降水演变特征,主要采用EOF分解和小波分析等方法,利用黄土高原区域51站1961-2000年降水资料,研究植被生长期降水旱涝特征,分析和比较了干年和湿年降水。结果表明:区域响应以一致的涝或旱为主,高原中北部为响应最敏感区;时间演变中1971年之前相对多雨,1985年后明显变旱,存在3～5a、8a左右的年际振荡,3～5a周期明显;高原东北部是干年降水响应最敏感区,是干旱最突出的地方;高原北部是湿年降水响应最敏感区,是降水偏多最突出的地方(易涝);旱年降水响应中局地性较强,湿年降水响应以全区一致为主。

The area of the Loess Plateau is about 517000 km2,the Loess plateau is the transition zone of climate from the semi-humid type to the semiarid type,it is sensitive to climate change and vulnerable in ecological environment,the agriculture depends on rainfall,and natural disasters,such as droughts and floods,occur frequently. In this paper,the characteristics of the long-term precipitation,droughts and waterloggings during crop growing period as well as the precipitation in dry years and wet years are analyzed based on the data of precipitation collected by 51 meteorological stations in the Loess Plateau during the period of 1961-2000 by using EOF and wavelet analysis so as to reveal the change characteristics of precipitation in the Loess Plateau during crop growing period. The results show that the regional response is dominated by droughts or waterloggings,and the response is the most sensitive in the central and northern parts of the plateau.For the temporal change,the precipitation was more before 1971,droughts have occurred more frequently since 1985, there are precipitation fluctuations of 3～5 years and 8 years respectively.The response of precipitation in dry years is the most sensitive in the northeastern part of the plateau,and the droughts are the most remarkable here.The response of precipitation in wet years is the most sensitive in the northern part of the plateau,where it is easy to occur waterloggings.