浙江省夏秋季降水量时空分布特征及趋势演变规律

夏、秋季是浙江省旱涝灾害最为频发的时段,研究夏、秋季降水量的时空分布特征和趋势演变规律,对防旱抗涝、防灾减灾有着重要的指导意义。根据1971-2009年浙江省65个台站6-11月的逐月降水量资料,利用趋势分析、等值线分布和EOF分解等方法研究浙江省近39a夏、秋季降水量的时空分布特征,再运用Morlet连续小波变化及功率谱检验等方法分析降水量的周期性演变规律。结果表明：近39a来,浙江省夏、秋季降水量总体呈现缓慢上升趋势,约每10a增加10.92mm。在空间上呈现东南沿海地区偏多,其它地区相对偏少的＂东-西＂向分布特征,在时间上存在不同时间尺度的周期振荡,以6～10a周期的振荡较为明显,并且8.7a周期振荡最显著,功率谱通过了95%的置信度检验。

Temporal and Spatial Distribution of Precipitation in Summer and Autumn and Its Trend Evolution in Zhejiang Province

Droughts and floods occurred frequently in summer and autumn in Zhejiang province,so it was very important for disasters prevention to study the temporal and spatial distribution and trend evolution of precipitation in summer and autumn.The temporal and spatial distribution and trend evolution of precipitation in summer and autumn was analyzed by using trend analysis,isoline distribution,EOF method and Morlet continuous wavelet transform,based on monthly precipitation data from 65 stations in summer and autumn during 1971 to 2009.The results showed that the precipitation increased at the rate of 10.92mm/10y in last 39 years.The spatial distribution showed decreasing trend from southeast to other areas.There was a different periodic oscillation,but concentrated in 6 to 10 years,and the 8.7-year cycle was most significant,which passed the power spectrum 95% confidence test.