呼伦贝尔市1971—2011年雷暴时空变化特征

Spatial and Temporal Distribution of the Thunderstorm over Hulun Buir City from 1971 to 2011

基于呼伦贝尔市1971—2011年16站地面天气现象观测资料,利用趋势分析、Mann-Kendall检验和经验正交函数(EOF)分析方法揭示呼伦贝尔市雷暴时空变化特征。分析结果表明:从时间变化看,呼伦贝尔市雷暴日近41 a总体呈减少趋势,雷暴主要出现在夏季,集中在7月,雷暴在13:00—15:00出现频次较高;初雷暴日和终雷暴日均呈现推迟趋势。从空间分布看,大兴安岭山区不但是雷暴的高发区,而且雷暴持续时间也较长。EOF分析结果显示,雷暴日主要EOF模态在空间上表现出一致的减少趋势以及东西反相位的特征。

Based on the meteorological data collected from 16 stations in the Hulun Buir city from1971 to 2011, temporal and spatial variation characteristics of thunderstorm were analyzed by using trend analysis, Mann-kendall test, and EOF(Empirical Orthogonal Function)analysis method. The results showed as follows. On the time scale,the general trend of the thunderstorm days over the Hulun Buir city reduced in the last 41 years. Thunderstorm occured mainly in summer, frequently in July, most frequently in a period from 13:00 to 15:00. Both of the start time and the end time of thunderstorm had an obvious trend of delay. On the spatial distribution, the area of Daxing'an Mountains was the area with high occurrence and long duration of the thunderstorm. The two dominant EOF modes from the EOF analysis results indicated that the thunderstorm days decreased over the whole of Hulun Buir and had opposite phases in east and west area.