莱芜市雷暴日的气候特征

深入了解莱芜市雷暴发生的气候规律以及演变趋势。利用1971~2000年莱芜市观测站资料,从雷暴的初、终日及绝对变率、雷暴日的年、月分布及变化趋势,以及雷暴初、终日的候平均气温阈值等方面进行了分析。随着年代的推移,初、终雷日的平均日期都更加趋于稳定,但终雷日的年际差异大;雷暴期相对稳定,年代际变化不大,总的趋势略有变短的倾向,年雷暴日数变化趋势是减少的,平均倾向率为每10年-2.5 d;雷暴的月分布基本呈单峰对称分布,7月份是雷暴的最为集中的1个月份;雷暴日与气侯平均气温的对应关系是,雷暴初日所对应的气侯平均气温为12℃,雷暴终日所对应的侯平均气温为14℃。从60年代到90年代,莱芜市平均初雷日、终雷日的变化不大。

Climate Characteristics of Thunderstorm Days in Laiwu City

The aim of the research was to thoroughly understand climate laws and evolution tendency of thunderstorm occurence in Laiwu city.Based on the data from the Observation Station of Laiwu city in 1971～2000,some aspects such as original and final thunderstorm day and its absolute rate of change,year and month distributions of thunderstorm days and their change tendency,pentad mean temperature threshold of original and final thunderstorm day were analyzed.With the process of ages,the average dates of original and final thunder day all trended to be stabilized,but annual difference of final thunder days was great.Thunderstorm stage was relatively steady,its change in different ages and years were not great,the whole tendency had slightly shortening trend,change tendency of thunderstorm days per year was decreasing and average tendency rate was – 2.5 days per 10 years.Month distribution of thunderstorm showed unimodal symmetrical distribution on the whole and July was one month that thunderstorm was the most concentrated.The corresponding relation between thunderstorm day and climatic average temperature was: climatic average temperature that corresponded with the original thunderstorm day was 12 ℃ and that corresponded with the final thunderstorm day was 14 ℃.Average original thunder day and final thunder day in Laiwu city had no great changes from 1960s to 1990s.