1961—2012年西宁地区雷暴气候变化特征分析

Climatic Change Characteristics of Thunderstorm in Xining City During 1961-2012

利用西宁地区4个测站雷暴观测资料，分析了1961--2012年西宁地区初、终雷暴日及雷暴日数的气候特征及其变化趋势。结果表明：西宁地区为雷暴多发区，年平均雷暴日数为41．6d，进入1990年代雷暴日呈快速减少趋势；初雷暴日提前，终雷暴日明显推后；3-11月均有可能出现雷暴，主要出现在5—9月，占总雷暴日数的93．7％，6-8月为雷暴高发期，占总雷暴日数的67．5％，平均初雷暴日为4月25日，终雷暴日为10月3日；大通雷暴出现最早，西宁结束较晚。春季、秋季平均气温稳定通过4～5℃的时间大致与初雷暴日和终雷暴日的时间相一致；西宁地区年雷暴日数于1997年发生突变。

Using the thunderstorm observational data of 4 stations in Xining area,the climatic characteristics and change trends of beginning days ,ending days and duration of thunderstorm during 1961-2012 in Xining area were analyzed. The results showed that Xining region was a thunderstorm prone area, the annual thunderstorm days was 41.6 d. In 1990s, thunderstorm days decreased rapidly, the beginning days of thunderstorm appeared in advance and ending days of thunderstorm significantly delayed. The thunderstorm might appear during March to November,and mainly occurred from May to September,which accounted for 93.7% of the total thunderstorm days. The thunderstorm＇s high-incidence period was from June to August,in which the thunderstorm days accounted for 67.5% of the total thunderstorm days. The average beginning day of thunderstorm was April 25th ,and the ending day was October 3rd. The earliest thunderstorm day appeared in Datong and the latest thunderstorm day appeared in Xining. The date of mean temperature of spring and autumn steadily pass 4-5℃ was in accordance with the beginning and ending days of the thunderstorm. The annual thunderstorm days in Xining City changed suddenly in 1997.