1959—2014年开平市暴雨的气候特征

Climatological Characteristics of Heavy Rains in Kaiping City in 1959 to 2014

利用开平市国家气象观测站1959—2014年逐日降水资料,通过数理统计、经验频率公式、复Morlet小波分析、Mann-Kendall突变检验等方法分析了开平市暴雨的气候特征,结果表明:开平市年平均暴雨日数为8.1 d,暴雨平均强度为83.6 mm;全年各月均有暴雨发生,主要集中在4—9月;暴雨月际分布呈双峰型,主峰5月、次峰8月;暴雨日数的年际变化很大,最多的年份达21 d,最少仅1 d;年暴雨日数与年暴雨降水量和年降水量有很好的相关性;暴雨初日多在3月6日—5月12日出现,终日多在8月20日—10月30日;小波分析表明开平市年暴雨日数存在着9和15年的显著周期,未来几年将经过短暂的暴雨偏少期,之后迎来暴雨多发期;突变检验分析表明开平市年暴雨日数整体变化趋势并不明显,未出现突变。

Using day-to-day rainfall data from national meteorological observation stations in Kaiping City from 1959 to 2004 and with the methods of mathematical and physical statistics, empirical frequency for- mula, complex Morlet wavelet analysis and Mann-Kendall abruptness test, we analyzed the climatological characteristics of heavy rains that happened in Kaiping. The result is shown as follows. Heavy rains hap- pened with an annual mean of 8.1 d with an average intensity of 83.6 mm. It is possible for heavy rains to take place all the year around but they concentrate in April to September. The monthly distribution of heavy rains is bimodal with the primary peak in May and the secondary peak in August. The number of heavy rain days varies much on the interannual scale with the most frequent year having 21 d but the least frequent year having only 1 d. The annual number of heavy rain days is well correlated with the annual rainfall of heavy rains and annual rainfall of all types of precipitation. The annually first day of heavy rain is mostly between March 6 and May 12, and the annually last day of heavy rain mostly between August 20 and October 30. As shown in the wavelet analysis, there are significant periods of 9 and 15 years in the annual average number of heavy rain days. In the next few years, heavy rains are expected to decrease for a short time before taking place frequently. As shown in the abruptness test, the overall trend of variation in the annual number of heavy rain days is not obvious, without any abrupt changes.