The Sorts of 500 hPa Blocking High in Asia and It’s Relations to Cold Vortex and Aestival Low Temperature in Northeast of China
The Sorts of 500 hPa Blocking High in Asia and It’s Relations to Cold Vortex and Aestival Low Temperature in Northeast of China
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发表时间：
2012
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通讯作者：
L. Gang
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作者：
L. Gang
利用1948 - 2009年NECP /NCAR逐日500 hPa高度场再分析资料，采用客观分类和公认的方法，分析了亚洲夏季阻塞高压的时空分布特征。结果表明，近62年夏季共发生阻塞事件1337次，其中阻塞次数最多的1337次，阻塞次数最少的1337次，阻塞次数最多的1337次，阻塞事件的活跃期以3-7天为主，占80.1%，根据阻塞事件的累积次数和日数，将阻塞事件划分为东向型（鄂霍次克海阻塞高压），向西型（阻塞高过乌拉尔山），中央型（贝加尔湖阻塞高压）和其它四种阻塞类型，分别占27.5%、30.4%、18.3%和23.8%。鄂霍次克地区的阻塞事件在世纪开始开始呈上升趋势，鄂霍次克地区的阻塞事件呈明显下降趋势，阻塞事件与东北冷涡有显著的正相关关系，阻塞高压是造成我国东北地区夏季低温的重要环流系统之一，在6月向西向型阻塞事件强烈活跃的年份，在20°E ~ 140°E，40°N ~ 55°N地区，850 hPa有一股较强的偏东气流，有利于冷空气从鄂霍次克地区东北路径侵入东北亚和我国东北地区。
Based on the daily NECP /NCAR reanalysis data of 500 hPa height field from 1948 to 2009,an objective classification and widely-agreed method was applied to analyze the temporal and spatial distributions of atmospheric blockings high in Asia during summer,In addition,the location and numbers of blockings high was automatically determined.The results show that there are 1 337 blocking events during the last 62 summers.According to the active period of blocking events,a period of 3-7 days are dominant during all the events which account for 80.1%.Based on the accumulative numbers and days,the blockings are divided into eastward type(blocking high over the Okhotsk Sea),westward type(blocking high over Ural Mountain),central type(blocking high over Baikal Lake) and the others,totally four types,occupying at 27.5%,30.4%,18.3%,and 23.8 %,respectively.Since 1990s,blocking events in Ural region are in a weak period,otherwise in Okhotsk region are in a strong period,but blocking events in Ural region begin taking upward trend at the beginning of 21st century.Bblockings in Okhotsk region take a clear downward trend.There is a significant positive relationship between blocking events and cold vortex in Northeast China,but a negative correlation between blocking events and temperature of Changchun and Harbin in summer.Blocking high is one of important circulation system which causes the low temperature in Northeast of China in summer.During westward type blocking events strongly active years in June,a strong easterlies air flow in 850 hPa is found over the region of 20°E-140°E,40°N-55°N,It is advantageous for cold air come from the northeast path in Okhotsk region to invade Northeast Asia and the northeast area in China.