湖南省近50年降水特征分析

Analysis on Spatiotemporal Characteristics of Precipitation in Hu′nan Province from 1961 to 2010

利用湖南省21个站点1961—2010年的日降水量数据和数理统计方法分析了近50a湖南省年、季、月降水特征,以期为水资源的开发和防洪等提供数据参考。结果表明:(1)湖南省降水量主要集中在4—8月,占全年的63.09%;春夏两季多雨,约占全年降水量的36%和35%,秋冬两季少雨,仅占17%和12%。(2)降水最大年份2002年达1 964.95mm,最小年份1974年仅为1 104.19mm,各年代年平均降水量比较接近,介于1 354.00～1 513.08mm之间;(3)全省多年平均暴雨量为305.75mm,主要集中在5—8月,50a年平均暴雨发生次数为4.1次;年暴雨量最大值为572.07mm,出现在2002年,而最少的年份仅有150.12mm,出现在1985年。总之湖南省降水量和暴雨量年内分布不均匀,季节变化明显,年际变化幅度较大,应按降水时空特征合理利用水资源且做好防洪措施。

Based on the daily rainfall data at 21 stations in Hunan Province, the spatiotemporal features of an- nual, seasonal and monthly rainfall in the period of 1961 to 2010 were analyzed in order to provide data sup- port for sustainable use of water resource and flood controlling. The results were as follows： The rainfall in Hu＇nan Province mainly occurred from April to August, which accounted for 63.09% of total precipitation of the whole year. Rainfall in spring and summer occupied 36% and 35% of the annual precipitation while 17% and 12% in autumn and winter. The maximum value of annual precipitation was up to 1 964.95 mm and the minimum value was only 1 104.19 mm. The average rainfall of every decade was closely and the decade pre- cipitation from 1960 to 2010 was between 1 354.00 mm and 1 513.08 mm. The average amount of rainstorm precipitation was 305.75 mm occurring mainly from May to August from 1961 to 2010, and the average event frequence of torrential rain was 4. 1 every year. The maximum value of annual torrential rain was up to 572.07 mm and the minimum value is only 150.12 mm. Results showed that the distributions of rainfall and heavy rainfall during the year in Hu＇nan Province were largely different and seasonal characters of precipitati- on and torrential rain were obvious. In additon, the differences among inter-annual precipitation and heavy rainfall were great. It was necessary to make use of water resources suitably and to take practice against flood according to the spatiotemporal characteristics of rainfall.