近50年陕南地区降水时空变化特征

应用滑动平均、累积距平、线性倾向估计、曼-肯德尔等方法研究陕南地区53 a降水量及降水日数的趋势和特征。结果表明:陕南地区降水年际变化大,年内分布不均匀,整体呈减少趋势;该区域南部及东南部降水呈现增加趋势,其余地区降水呈现减少趋势,特别是西部地区降水减少明显;陕南地区近年的降水量减少主要以春季和秋季的显著减少为主;总降水日数、小雨日数、中雨均呈现减少趋势,大雨日数和暴雨日数变化不明显;大雨以上日数与年均降水量存显著正相关,是影响年均降水量的重要因素。21世纪以来,夏季降水量和大雨以上日数呈增加趋势,应引起相关部门重视。

Spatiotemporal variability of precipitation in south of Shaanxi province in recent 50 years

Using the moving average method, the cumulative departure method, the linear trend estimation, and the Mann-Kendall method, the trends and characteristics of precipitation and precipitation days in South of Shaanxi province (SSP) were analyzed for recent 53 years in this research. The result showed that, the inter-annual variation of precipitation in SSP was large with uneven distribution within the year, and it had an overall decreasing trend. The precipitation in southern and southeast of SSP had increasing trends, while the precipitation in other areas had decreasing trends, especially in western area. Precipitation decrease was mainly found in spring and autumn in SSP in recent years. All of the total precipitation days, light rain days, and moderate rain days decreased. Both heavy rain days and storm days changed little. The heavy rain days and storm days had significantly positive correlation to annual precipitation amount, and both were important factors that affected average annual precipitation. Since the new century began, summer precipitation, heavy rain days and storm days have increased, which should attract the attentions of related department on the issue of improving flood prevention warning and rapid-response ability.