摘要
根据阻高的天气学定义,利用1950—2004年NCEP/NCAR 500 hPa逐日位势高度场、风场再分析资料,检索出近55 a欧亚大陆中高纬地区出现阻高1 169次。统计表明,阻塞高压中心的频次分布具有明显的季节性地理差异。春季阻高活动多集中在乌拉尔山地区;夏季阻高活动频繁,阻塞形势复杂,阻高频繁活动区域有4个,分别是乌拉尔山地区、贝加尔湖以西地区、贝加尔湖以东地区和鄂霍次克海地区;秋季是阻高发生最少的季节;冬季阻高高发区位于乌拉尔山附近。贝加尔湖地区仅夏季出现阻高的日数就占到全年的69%。夏季欧亚大陆阻塞高压中心逐日累积频次存在明显的随时间东传特征。55 a中平均每年夏季欧亚大陆中高纬上空有11 d存在双阻形势,占夏季阻高日数的1/5左右。欧亚大陆阻高活动具有明显的年际变化,不同地区的年际变化特征各有不同。
Activity of blocking high over Eurasia continent is examined according to data of 500 hPa geopotential height and zonal winds for the period 1950-2004 ,which are provided by NCEP/NCAR. Results show that blockings in Eurasia posses distinct seasonal variations and geographic diversities. In spring blockings occun＇ed frequently over the Ural Mts. In summer blockings occun＇ed frequently over four regions, namely the Ural Mts, West of the Lake Baikal, East of the Lake Baikal, and the Sea of Okhotsk. Much fewer blockings occun＇ed in autumn. In winter most blockings occun＇ed over around the Ural Mts. The occun＇ence frequency of blockings over the Lake Baikal in summer accounts for 69 percent of its annual total. There is an intraseasonal variation of the occun＇ence frequency of blocking in Eurasia with a significant period of 30-60 days as well as eastward propagation of the blocking high centers in summer. In addition, blocking activities have significant interannual variations, which behave differently in various areas.
出处
《南京气象学院学报》
CSCD
北大核心
2007年第3期338-344,共7页
Journal of Nanjing Institute of Meteorology
基金
2005年江苏省"六大人才高峰"项目
江苏省气象灾害重点实验室基金资助项目(KLME05012)
关键词
阻高
地理分布
年际变化
季节内变化
blocking
geographic distribution
interannual variation
intra-seasonal variation
