甘肃黄土高原各级降水和极端降水时空分布特征

利用甘肃黄土高原地区1960－2011年12个及周边4个站点的逐日降水观测资料，用阈值检测方法计算出甘肃黄土高原地区极端降水的阈值并运用气候线性趋势、多项式拟合、反距离加权法、Mann-Kendall检验、Morlet小波、R／S方法分析了近52a甘肃黄土高原各级雨量和R95极端降水的时空变化特征及对未来进行预测。结果表明：①近52a来甘肃黄土高原春季以小雨为主，夏、秋季以暴雨为主，冬季以大雪为主，R95极端降水主要集中在夏季；②春、秋季主要以大雨降水强度最强，夏季暴雨降水强度最强，冬季则为大雪；R95极端降水强度夏季降水强度最强。③小雪呈显著增加，微雨、中雨、大雨、微雪、R95极端降水量均呈显著减少；④微雨量、小雨量、中雨量、大雨量、R95极端降水量与年降水总量有很好的相关性，对年降水总量有很好的响应；⑤在空间分布上，各量级降水和R95极端降水大部分存在减小趋势，减小区主要集中在西南部和东北部；⑥各量级降水和R95极端降水突变年份不尽相同；⑦各量级降水和R95极端降水在不同的时间序列存在长短不同的周期震荡；⑧R／S分析表明不同量级降水和R95极端降水的未来变化趋势和过去一致。

The variation characteristic of different levels of precipitation and extreme precipitation in Loess Plateau of Gansu province region in recent 52 years

The data on the year-by-year daily precipitation of 12 meteorological stations and 4 around in loess plateau of Gansu Province Region was selected, the thresholds of extreme precipitation were measured by the method of threshold detection as well as climate linear trend analysis, polynomial fitting, inverse distance weighted, Mann-Kendall test, Morlet wavelet analysis and R/S analysis to analyze. The following results were obtained in this paper. ①Different levels of precipitation share different proportion of each quarter, the light rain was mainly in spring, the storm rain was mainly in summer and autumn and heavy snow was mainly in winter, R95 extreme precipitation was mainly in summer; ②The heavy rain precipitation intensity was strongest in spring and autumn, the storm intensity was strongest in summer and heavy snow in winter; R95 extreme precipitation intensity was strongest in summer; ③Light snow was increase significantly, drizzle rain, moderate rain large rain and R95 extreme precipitation were decrease significantly; ④The drizzle rain, light rain, moderate rain large rain and R95 extreme precipitation have good correlation with annual precipitation and made the greatest contribution to the annual precipitation; ⑤In spatial distribution, Different levels of precipitation and R95 extreme precipitation were decreasing, the decreasing area are mainly concentrated in the southwest and northeast; ⑥Different levels of precipitation and R95 extreme precipitation were exist abrupt change except moderate snow; ⑦It is demonstrated that different vibration periods were displayed very clearly in the different levels of precipitation and R95 extreme precipitation in recent 52 years; ⑧R/S analysis to show that the future of the levels of precipitation and R95extreme precipitation of trends are consistent with the past.