1954～2017年台山市暴雨气候特征

Climatological Characteristics of Rainstorm in Taishan City from 1954 to 2017

采用Excel和复Morlet小波函数等统计分析方法,分析台山市1954~2017年暴雨的气候特征。结果表明:台山市年平均暴雨日数为9.2 d,平均暴雨强度为87.5 mm/d。一年四季均有暴雨发生,主要集中在4~9月。暴雨的月变化表现为明显的双峰型,主峰在5~6月,次峰在8月。持续暴雨占暴雨总日数的29.4%,持续3 d以上的暴雨均出现在汛期,2次持续5 d的暴雨均出现在后汛期。暴雨初日具有逐渐提前的特征,终日推迟特征不明显。年暴雨日数的年际差异很大,最多20 d,最少1 d。小波分析显示,台山市暴雨日数存在准6 a和准27 a的周期变化,预测台山市未来几年将继续处于暴雨偏多期。

The climatological characteristics of rainsto rm in Taishan City from 1954 to 2017 were analyzed by using Excel and complex Morlet wavelet function. The results showed that interannual average days of rainstorm was 9.2 d with an average intensity of 87.5 mm/d. It was possible for heavy rains to take place all the year round, but the heavy rainstorms were mainly taking place from April to September. The monthly change of heavy rains was bimodal with the primary peak in May to June and the secondary peak in the August. The days of continuous rainstorms were accounted for 29.4 % of the total rainstorms. The rainstorms lasting more than 3 d occurred during the flood season, and heavy rains lasting 5 d for 2 rounds occurred during the subsequent flood season. The first day of heavy rain was ahead of time, and the end day of heavy rain was postponed but not obviously. The number of heavy rain days had a great interannual change, 20 days different at most and 1 day different at the least. The wavelet analysis showed that there was a periodic change of a quasi period of 6 years and a quasi period of 27 years in the number of heavy rain days in Taishan City, and it was thus predicted that more heavy rains would occur continuously in the coming years in Taishan City.