皖北平原近56年来降水时间分异规律研究

Time Variability of Precipitation of Northern Plain in Anhui Province in Past 56 Years

利用皖北平原5个气象站1957-2012年逐月降水资料,运用线性趋势分析、距平分析、小波分析和Mann-Kendall法对该区年降水量和季节降水量进行年际和年代际分析,揭示该区降水量时间尺度变化特征,并分析其降水序列的周期变化和突变点。结果表明:(1)皖北平原降水趋势总体呈增长趋势,降水倾向率为8.51mm/10a,其中距平33年为负,23年为正。1960年代、1990年代和2000年代为丰水期。除夏季外,春季、秋季和冬季降水量总体变化趋势不显著,降水倾向率分别为-3.59mm/10a、-2.50mm/10a和2.13mm/10a,夏季降水增长趋势明显,降水倾向率为12.93mm/10a。(2)小波分析结果显示,区域降水量存在不同尺度的周期变化,普遍存在10~15年的震荡周期,5~10年的次周期和3~5年小周期。(3)皖北平原年降水量经滑动t检验,在1994年发生突变,但变化不明显,夏季突变与年降水量一致,春季、秋季和冬季降水量时间上没有发生突变。

A total of 56 years of monthly precipitation data in 5 meteorological stations of the Northern Plain in Anhui Province from 1957 to 2012 were applied by trends analysis,wavelet analysis and Mann-Kendall abrupt change analysis to analyze time variation features of interannual and interdecadal precipita-tion.The results indicated that:(1)the annual precipitation showed a rising trend with the tendency rate 8.51 mm/10 a.more than the average annual precipitation in 33 years and less in 23.And there were 3 a-bundant water periods in 1960,1990 and 2000.In addition,we found that the seasonal variation trend of precipitation was not significant except in summer at the rate-3.59 mm/10 a,12.93 mm/10 a,-2.50 m/10 a and 2.13 mm/10 a,respectively;(2)Wavelet analysis indicated that precipitation series existed oscilla-tion period of 10 to 15 years,time period of 5 to10 years and small period of 3 to 5 years of the Northern Plain in Anhui Province in 56 years;(3)After the sliding test,the annual precipitation mutation occurred in 1994 but with no obvious change and mutation,which was in line with summer.Nevertheless,there were no mutations in spring,autumn and winter.