西伯利亚高压强度与北大西洋海温异常的关系
投稿时间: 2015-12-18  最后修改时间: 2016-05-05  点此下载全文
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作者单位E-mail
李栋梁 南京信息工程大学大气科学学院 lidl@nuist.edu.cn 
蓝柳茹 南京信息工程大学大气科学学院 liuru_lan@126.com 
基金项目:国家重点基础研究发展计划(973计划)项目(2013CB430202);公益性行业(气象)科研专项(GYHY201506001-1)共同资助
中文摘要:利用NCEP/NCAR再分析资料和NOAA海温等资料,采用EOF、相关分析等方法,分析了西伯利亚高压(SH)强度和北大西洋海表温度( SST) 的变化特征,揭示了二者联系及其时空变化。结果表明:(1)冬季SH在1960s中后期开始异常偏弱,2003年后又稍显增强。(2)四季北大西洋SST指数(全区平均SST的标准化距平)均在1960s中期由偏高变为偏低, 1990s末后又偏高。北大西洋海温三极子位相由正转负的时间在春冬季(1970s初)晚于夏秋季(1960s初),而后均在1990s中期后进入正位相。(3)四季北大西洋SST指数的异常偏高(低)和北大西洋海温三极子正(负)位相均有利于冬季SH偏强(弱),但前者与SH的关系更显著,且从秋至冬增大到最强。北大西洋北部和西南部始终是影响SH强度的关键区,但SH对北部SST异常的响应范围在冬季最大,夏秋季较小,而对西南部的响应范围在夏季最大,冬季最小。(4)当冬季大西洋SST指数异常偏高时,下游激发出的罗斯贝波列可使乌拉尔山高压脊显著加强,脊前的西北气流将较强的负涡度输送到SH上空,使SH上层负相对涡度平流增大,高层辐合和低层辐散均增强,整个对流层下沉气流深厚,促使SH增强,反之亦然。
中文关键词:西伯利亚高压强度  北大西洋海温异常  时空联系  相关分析
 
Relationship between Siberian High Intensity and SST Anomaly in the North Atlantic
Abstract:By using the NCEP /NCAR reanalysis data, Sea Surface Temperature(SST) data from NOAA and other data,the variation characteristics of Siberian High (SH) and SST in North Atlantic are investigated with methods of EOF and correlation analysis.Moreover, their connection and its temporal and spatial change are also revealed. The results are as followings: (1) the winter SH intensity changed from strong to weak in the mid to late 1960s, but enhanced slightly again after 2003. (2) The North Atlantic SST index in four seasons all deceased in the mid 1960s,but they rose again from the late 1990s. The time in which North Atlantic SST tripole converted from positive phase to negative phase came relatively later in spring and winter(early 1970s) than summer and autumn(early 1960 s), but then the tripole of four seasons all turned into positive phase again in the mid 1990s. (3) The anomalous highness(lowness) of North Atlantic SST index and the positive(negative) phase of North Atlantic SST tripole at all seasons both can make winter SH strengthen (weaken). Further by comparison, the relation between the former and SH intensity is more outstanding, and their correlation gradually increases to the strongest from autumn to winter. At all seasons the northern part and southwest part of North Atlantic both are the key regions that has a positive impact on SH intensity. the SH’s response range to the SST anomaly of the north part is widest in winter and smaller in summer and autumn, while for the SST anomaly of the southwest part, the SH’s response range is maximum in summer and minimum in winter. (4) When the North Atlantic SST index is anomalously high in winter, a Rossby wave train is aroused in the downstream Eurasia,making the Ural mountain high-pressure ridge enhanced prominently, then bigger negative vorticity is delivered to the up levels of SH by the northwest airstream in front of the Ural ridge. As a result, the negative relative vorticity advection over the SH increases, along with the reinforce of the high level convergence and low level divergence, the downdraft in the whole troposphere grows significantly as well. The above situation causes the enhancement of SH intensity, and vice versa.
keywords:Siberian High intensity  North Atlantic SST Anomaly  time-space relationship  correlation analysis
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