湖北省梅雨期降水集中度和集中期研究

The Features of Precipitation Concentrations During Meiyu Period Over Hubei Province

利用湖北省32个台站1960—2007年梅雨期逐候降水资料,分析湖北省梅雨期降水集中度和集中期时空分布特征及变化规律,同时对多雨年和少雨年的集中度和集中期进行比较。结果表明:降水集中度和集中期能够定量表征降水量在时空场上的非均一性,降水集中度平均为0.389,最大值为0.642,最小值为0.216;集中期平均为5.600候,最大值、最小值分别为8.450候和3.053候。梅雨期降水集中度20世纪60年代至70年代呈减小趋势,80年代至21世纪前7年呈增大趋势;降水集中度的EOF分析显示,第一特征向量表现为全省一致型,第二特征向量表现为鄂东南与鄂西北地区的反相,第三特征向量表现为鄂中平原地区和湖北东西部山区的降水集中度反相。多雨年的降水集中度比少雨年的偏小;多雨年的降水集中期比较集中,少雨年的比较复杂。

Based on the precipitation data of 32 gauging stations during Meiyu period from 1960 to 2007 in Hubei province, precipitation concentrations and the associated spatial and temporal patterns are analyzed with the precipitation concentration degree （PCD） and concentrated period （PCP）, and two parameters comparing respectively in the more precipitation years with those in the less precipitation years. The results indicate that：the PCD and PCP can quantitatively represent the non-uniformity properties of the precipitation spatio-temporal distribution,the average PCD is 0.389 with the maximum of 0.642 and the minimum of 0.216; the average PCP is 5.600 pentads with the maximum of 8.450 pentads and the minimum of 3.053 pentads. The PCD during Meiyu period is decreasing from the late of 1960s to 1980s, and increasing from 1980s to the 21st century. The EOF analysis of PCD shows that： the primary eigenvector represents the conformity PCD variation throughout Hubei province; the second eigenvector represents the reverse PCD variation in the south-east areas to the north-west areas, and the third eigenvector shows that the PCD variation in Jianghan plain areas presents the reversed phase to that in the east and west mountains. In the more precipitation years, the PCD is smaller than that in the less precipitation years; the PCP is more concentrated than in the less precipitation years.