粤东北雷暴时空的变化特征及环流背景分析  

Analysis of the characteristics of spatial and temporal variations of thunder and their circulation background in northeast Guangdong Province

作　　者：段海花 侯学源 甘海 

机构地区：[1]河源市气象局,广东河源517000

出　　处：《广东气象》2012年第6期4-8,共5页Guangdong Meteorology

基　　金：中国气象局气候变化专项(CCSF-09-03);广东省气象局2011B18项目共同资助

摘　　要：统计分析1965～2008年粤东北12个站点的雷暴气候资料。结果表明:粤东北雷暴日总体呈明显减少的趋势,年代差异较大,并在1986年发生了减少性突变;在空间分布上有自北向南逐渐增加的特征;从气候趋势系数的空间分布来看,全区皆呈一致的减少趋势;一致性和西北-东南反位相异常变化特征是粤东北雷暴日的两个主要空间模态。利用NCEP/NCAR再分析资料,分析夏季雷暴日异常年500 hPa高度场和850 hPa风场特征发现,在正(异)常年500 hPa位势高度偏低,副热带高压偏弱、位置偏东,南支槽显著加深,中高纬阻塞高压偏强;850 hPa西太平洋和南海的2支气流使粤东北处于水汽辐合区。Statistical analysis is performed of the climatological data of thunder for 12 sites of observation in the northeastern part of Guangdong province from 1965 to 2008. The results showed that the number of thunder days shows a general tend of significant decrease in the region with large interdecadal variations, and an abrupt change occurred in 1986 that brought the number downwards. The number of thunder days shows a trend of increasing from the north to the south and the spatial distribution is consistently decreasing of the coefficient of climatological trends throughout the region. Two main spatial modes-one being consistent and the other NW-SE anti-phased-are present in the anomalous variation of the number of thunder days in this region. Using the NCEP/NCAR reanalysis, this work studies the 500 hPa geopotential heights and 850 hPa winds associated with the abnormal years of the number of summer thunder days with the finding presented as follows： the 500 hPa geopotential heights are relatively low, the subtropical high is relatively weak and located relatively eastward, the southern branch of the westerlies is significantly deep, and a mid-and higher-latitude blocking high is relatively strong in the abnormal years. Besides, two 850 hPa airflows over the West Pacific and South China Sea are so situated that the eastern part of Guangdong is in a zone of water vapor convergence.

关 键 词：气候学 雷暴 气候特征 环流背景 粤东北 

分 类 号：P46[天文地球—大气科学及气象学]