| 西伯利亚高压强度与北大西洋海温异常的关系 |
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| 引用本文： | 李栋梁,蓝柳茹.西伯利亚高压强度与北大西洋海温异常的关系[J].大气科学学报,2017,40(1):13-24. |
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| 作者姓名： | 李栋梁 蓝柳茹 |
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| 作者单位： | 南京信息工程大学 气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044;南京信息工程大学 气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044;柳州市气象局, 广西 柳州 545001 |
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| 基金项目： | 公益性行业（气象）科研专项（GYHY201506001-1）；国家重点基础研究发展计划（973计划）项目（2013CB430202） |
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| 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,研究了西伯利亚高压(Siberian High,SH)强度和北大西洋海表温度(SST)的变化特征,揭示了二者的联系及其时空变化。结果表明:1)冬季SH在1960s中后期开始偏弱,2003年后略增强。2)各季北大西洋SST指数(全区平均SST的标准化距平)均在1960s中期后偏低,1990s末后偏高。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)各季偏高(低)的北大西洋SST指数和海温三极子正(负)位相均有利于冬季SH偏强(弱),但前者与SH的关系更显著,且冬季最强。北大西洋北部和西南部是影响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,而对西南部的响应范围在夏季最大。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使乌拉尔山高压脊加强,使SH上空负相对涡度平流增大,高层辐合和低层辐散增强,整个对流层下沉气流深厚,促使SH增强,反之亦然。
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| 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 |
| 收稿时间： | 2015/12/18 0:00:00 |
| 修稿时间： | 2016/5/22 0:00:00 |
Relationship between the intensity of the Siberian High and the SST anomaly in the North Atlantic |
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| LI Dongliang and LAN Liuru.Relationship between the intensity of the Siberian High and the SST anomaly in the North Atlantic[J].大气科学学报,2017,40(1):13-24. |
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| Authors: | LI Dongliang and LAN Liuru |
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| Institution: | Key Laboratory of Meteorological Disaster, Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing 210044, China;Key Laboratory of Meteorological Disaster, Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD), Nanjing University of Information Science & Technology, Nanjing 210044, China;Liuzhou Meteorological Bureau, Liuzhou 545001, China |
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| Abstract: | As an important component of the East Asian winter monsoon,the Siberian High(SH) can cause low temperatures,snowy weather and strong wind,which has a substantial influence on the winter climate of China.In order to mitigate the effects of the SH,it is important to study in depth the climate characteristics of the SH and its impact factors.Using NCEP/NCAR reanalysis monthly data and sea surface temperature(SST) data from NOAA and other data for the period 1951-2014,this study investigates the variational characteristics of the SH and SST in the North Atlantic,employing the methods of empirical orthogonal function(EOF) analysis,conventional synthesis analysis,Gaussian filtering,and the t-test of statistical significance.Moreover,their connection and its temporal and spatial changes are also revealed,based on correlation analysis and regression analysis.The results are as follows:(1) The intensity of the SH in winter changed from strong to weak in the mid to late 1960s,but enhanced slightly again after 2003.The SH expands outward significantly in strong anomaly periods,whereas it shrinks obviously in weak anomaly periods;and the swing amplitude of its east and north edge is bigger than that of the west and south edge.(2) The North Atlantic SST index(normalized anomaly value of the whole region''s average SST) decreased in all seasons in the mid-1960s,but rose again from the late 1990s.The time in which the North Atlantic SST tripole converted from positive to negative phase came relatively later in the early 1970s(spring and winter) than in the early 1960s(summer and autumn),but then the tripole of all four seasons turned into a positive phase again in the mid-1990s.The phase variation of the North Atlantic SST tripole commonly induces the change of the North Atlantic SST index.(3) An anomalously high(low) North Atlantic SST index and positive(negative) phase of the North Atlantic SST tripole in all seasons can together make the winter SH strengthen(weaken).Furthermore,by comparison,the relationship between the former and the SH intensity is more outstanding,and their correlation gradually decreases to a minimum from spring to summer,meaning the period is the relationship conversion period,and then gradually increases to a maximum from autumn to winter.In all seasons the northern part and southwest part of the North Atlantic are both key regions having 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;whereas 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,the winter 500 hPa height above its northern waters is abnormally high owing to the heating of the underlying surface,and a Rossby wave train is excited in downstream Eurasia,making the Ural Mountains'' high-pressure ridge enhance prominently,and resulting in a larger negative vorticity being delivered to the upper levels of the SH by the northwest airstream in front of the Urals ridge.As a result,negative relative vorticity advection over the SH increases and,along with the reinforcement of high-level convergence and low-level divergence,the downdraft in the whole troposphere also grows significantly.The above situation causes the enhancement of SH intensity,and vice versa. |
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| Keywords: | Siberian High intensity North Atlantic SST anomaly spatiotemporal relationship correlation analysis |
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