江浙沪地区夏季降水时空变化特征研究

Temporal and Spatial Distribution of Precipitation in Summer in the Jiangsu-Zhejiang-Shanghai Area

利用50年江浙沪地区30个气象基准台站的逐日降水资料,采用线性回归分析、Mann-Kendall（MK）趋势和突变分析、Morlet小波分析、GIS技术和EOF分解技术分析和研究了1961-2010年江浙沪地区降水时空变化特征。结果表明,江浙沪地区50年来夏季降水量呈现出一个总体上升的趋势,上升幅度8月〉7月〉6月;对江浙两省夏季降水量距平进行EOF分解,发现江浙地区降水量距平总体呈现出一致的增加趋势,江苏省降水距平场呈＂西北-东南＂向分布,浙江省的降水距平场呈＂东北-西南＂向分布;江浙沪地区降水量和各月降水量均有3年左右的振荡周期,此外还各自存在3~8年不等的振荡周期,16年以上的年代际周期不显著。

Basing on the daily precipitation data of 30 meteorological stations from 1961 to 2010 of Jiangsu-Zhejiang-Shanghai area, the temporal and spatial distribution of summer rainfall in Jiangsu-Zhejiang-Shanghai area was analyzed by the linear regression analysis, Mann-Kendall（M-K） trends and mutation analysis, Morlet wavelet analysis, GIS technology and EOF analysis. The results showed that, in 50 years, summer precipitation in Jiangsu-Zhejiang-Shanghai area presented an overall trend. Furthermore, the growth of precipitation in August was faster than in July, the growth of precipitation in July was faster than in June. Using spatial decomposition of summer rainfall anomaly by EOF, it was shown that precipitation anomaly presented a consistent increase general trend in Jiangsu-Zhejiang area. The precipitation anomaly field in Jiangsu province presented the distribution of northwest to the southeast. The precipitation anomaly field in Zhejiang province presented the distribution of northeast to the southwest. Annual precipitation and monthly precipitation in Jiangsu-Zhejiang-Shanghai area had an oscillation period of about 3 years. Besides, these regions existed the oscillation period from 3 years to8 years independently. However, the period more than 16 years was indistinctive.