1960年以来山西秋季连阴雨的气候特征分析

Analysis of Climate Characteristics of Continuous Autumn Rain during the Past 50 Years in Shanxi Province

利用山西省66个测站1960—2009年秋季（9—11）月的逐日降水量，采用线性倾向估计、累积距平法、EOF及Morlet小波分析方法，系统地分析了山西秋季连阴雨的变化趋势和时空结构特征，建立了秋季连阴雨强度指数模型。结果表明：山西秋季年际区域性连阴雨次数和阴雨日数呈明显的线性减少趋势，过程雨量呈波动上升趋势，连阴雨次数的累积距平表现为“三升两降”型变化；山西秋季连阴雨的年际和年代际变化特征明显，1960—1970年代中期，有5～6年的周期变化，1990年代后期有2年的周期变化特征，年代际变化呈“波动状”变化规律；全省秋季连阴雨从南到北呈递减分布，除北部的天镇、山阴、繁峙等呈增加趋势外，各代表站表现为一致的减少趋势，南部、东南部及五台山为连阴雨多发区，大同盆地、忻州盆地、太原盆地为少发区；山西秋季连阴雨存在2～3年、8年左右的显著振荡周期。1970年代中期到1980年代中期，8年左右振荡周期的振幅最大，能量最强，是周期振荡最强的阶段。

Based on day-by-day precipitation data of 66 stations in autumn during 1960 -2009 in Shanxi Province （September-November） , by using methods such as linear trend estimation, cumulative departure method, EOF and Morlct wavelet analysis, change trend and spatial-temporale structure characteristics of continuous autumn rain in Shanxi province are systematically analyzed and an intensity index model of continuous autumn rain is estab- lished. Results show that numbers and days of regional continuous autumn rain in Shanxi province are of an obvious linear decrease tendency. The process rainfall appears rising trend and the number of continuous raing cumulative departure shows the pattern of three ascents and two descents. It turned out that the continuous autumn rain in Shanxi province had significant yearly and decadal variation character. There is a 5 -6 years periodic change dur- ing the 60g to the mid 70＂s, and 2 years periodic variation character in the late 90＂s, and the decadal variation shows an undulating change rule. The continuous autumn rain in Shanxi province is degressive from the south to the north, in addition to the northern Tianzhen, Shanyin and Fansi shows an increasing trend, the last representative stations are consistent with the decreasing trend. Continuous rain occurred easily in southern, southeast and Wutai mountain area, less easily in Datong basin, Xinzhou basin and Taiyuan basin. Continuous autumn rain in Shanxi province has 2 -3 years and 8 years remarkable oscillating period. During the mid 70 ＇s to the mid 80＇s, approxi- mately 8 years has maximum amplitude and the strongest power, was the strongest periodic oscillation period.