中国黄土高原地区典型旱涝年降水特征

利用黄土高原40 a降水资料,采用EOF、小波分析和计算分维数等方法,确定典型旱涝年份,分析典型旱涝年降水量和频次变化特征。结果表明,黄土高原涝年降雨量自西向东递增,旱年由北向南递增;年降水频次时间分布的分维数涝年大于旱年,涝年降水间隔变化复杂程度超过旱年;旱涝年降水频次变化的周期谱存在较明显差异,涝年周期复杂,以短周期为主要特点,旱年长周期突出;大地形在涝年对降水的再分配能力远大于旱年;旱涝年降水频次的差异上大雨以上降水更为明显。

Rainfall Variations of Typical Drought and Waterlog in Loess Plateau of China

By investigating distribution and change of rainfall from 1961 to 2000 with analyses of empirial orthogonal function,wavelet and fractal dimension,the typical drought and waterlog were confirmed.Results showed that the amount of rainfall increased from the west to the east in the Loess Plateau in waterlog year,and from the north to the south in drought year.The fractal dimension of waterlog rainfall frequency was bigger than that of drought year.The interval of rainfall was more complicated in the waterlog year than in drought year.The rainfall frequency had differences between drought and waterlog year.The short variation period was dominant in waterlog year,and long period in drought year.The power of distributed rainfall by mountains was stronger in waterlog year than in drought year.Heavy rain frequency was much more variable in waterlog year than drought year.