1951—2010年大连市雷暴气候统计特征

Climatic characteristics of thunderstorm in Dalian from 1951 to 2010

利用1951—2010年大连市雷暴资料,通过数理统计、Mann-Kendall和Morlet小波分析等方法研究大连市雷暴的气候特征。结果表明:近60 a大连市年平均雷暴日较多,年际和年代际变化较大,年雷暴日呈增加趋势,每10 a雷暴日增加0.5 d。初雷日明显提前,终雷日明显推迟。雷暴有较强的季节性特点,集中出现在5—9月,而6—8月占近6成;夏季多于秋季,冬季最少。逐月平均雷暴分布与月平均气温、月降水量呈同相单峰形,7月雷暴出现高峰值,10月雷暴锐减。雷暴出现频率以02—06时为最高,16—20时为最低。雷暴日数的年际和年代际变化存在不显著的2—4 a和14—16 a振荡周期,并在1972年发生突变。

Using the thunderstorm data from 1951 to 2010 in Dalian, the climatic characteristics of the thunder- storms were analyzed in terms of methods of a mathematical statistics, a Mann-Kandall test and a Morlet wavelet a- nalysis. The results show that the mean annual thunderstorm days increase in the recent 60 years, and the variation of the inter-annual and inter-decadal thunderstorm is significant. The annual thunderstorm day is in an increasing trend, and its ratio is 0. 5 d/decade. The first thunderstorm date is ahead and the last thunderstorm date delays nota- bly. The seasonal variation of thunderstorm is significant, and the frequency of thunderstorm is higher in summer than in autumn, while it is lowest in winter. Most thunderstorm appear during May to September, and those from June to August account for 60%. There is a peak value for the mean monthly thunderstorm day, so are the mean monthly air temperature and the monthly precipitation. The maximum thunderstorm day occurs in July, and it de- creases rapidly in October. Thunderstorm often occurs from 02：00 to 06：00 and seldom happens from 16：00 to 20：00. The thunderstorm days show 2-4 years and 14-16 years oscillating periods for inter-annual and inter-decadal variations ,though these two periods are not significant. An abrupt change occurs in 1972.