1951—2014年杭州市降水特性研究

杭州市为长三角地区重要的城市之一,在全球气候变暖背景下对其进行降水特性分析具有重要的科学与现实意义。选取杭州站1951—2014年间实测逐日降水资料,采用M-K检验、线性趋势分析及相关水文统计方法对地区降水变化特征进行研究。结果表明,近64 a杭州市年降水量变化不显著,但年降水天数显著减少,即单次降水强度有增大的趋势;冬夏两季节降水量增多,而降雨日数发生减少或没有变化,春秋季降水量及降水日数发生显著减少,夏涝秋旱情况有所加剧;降水量年内分配不均,降水主要集中在3—9月份,该区间降水量占全年降水量的75%,降水日数占全年降水日数的65%左右;最大日降水主要集中在6月份,64 a间最大日降水发生在6月份的频次为15次,占23.4%。研究成果可为中、短期降水趋势预测及水资源开发利用和防灾减灾提供参考。

Characteristics of Precipitation in Hangzhou City from 1951 to 2014

Analyzing the characteristics of precipitation in Hangzhou, an important city in the Yangtze River Delta, is of vital scientific and practical significance. According to daily precipitation data of Hangzhou Station from 1951 to 2014, the characteristics of precipitation variation was investigated by using M-K test, linear trend analysis and hydrological statistical method. Results revealed that: (1) The change trend of annual precipitation in Hangzhou in the past 64 years was insignificant; but the number of days of precipitation has been decreasing, indicating an increasing trend of single precipitation intensity. (2) In winter and summer, precipitation has been increasing, yet the number of precipitation days has decreased or remained unchanged; while in spring and autumn, precipitation and number of precipitation days both declined significantly. Flooding in summer and drought in autumn has exacerbated. (3) Precipitation was unevenly distributed in one year and mainly concentrated in March-September, accounting for 75% of yearly precipitation; the number of precipitation days in March-September accounted for about 65% of the annual precipitation days. (4) Maximum daily precipitation mainly concentrated in June; daily precipitation reached the maximum in June for 15 times over 64 years, accounting for 23.4%. The results offer scientific reference for forecasting short-term and mid-term precipitation trend, water resources development and utilization, and disaster prevention and reduction.