中国黄土高原地区大雨频次演变特征

The Spatial and Temporal Variations of Heavy Rain Frequency over China Loess Plateau

利用黄土高原40年降水资料,研究了该区域大雨以上降雨频数演变。结果表明:黄土高原地区大雨频次是自西北向东南逐渐增多;大雨频次存在减少趋势;小波分析表明大雨频数存在4～5年、8年左右和15年左右的周期振荡;大雨频数存在4个特征区域,各区变化幅度和时段明显不同。

By use of 40 years' precipitation data of loess plateau, the evolvement of heavy rain frequency in this region is studied. The results show that, in the loess plateau, frequency of heavy rain increases from NW toward SE and, in the whole, the frequency tends to decrease. Wavelet analysis indicates that heavy rain frequency varies in periods of 4～5years, about 8 and 15 years. There are 4 characteristic regions of heavy rain frequency, where the variation amplitude and time intervals are different.