NORTHERN HEMISPHERE SUMMER TELECONNECTIONS INTERANNUAL OSCILLATION AND ITS POSSIBLE RELATION TO ENSO CYCLE     

谭言科  胡邦辉  何金海 《热带气象学报(英文版)》2000,6(1):46-53

The intense of Northern Hemisphere summer East Asia/Pacific and snow-forced pattern teleconnections have been documented in terms of 43-year summer 500 hPa height data. The analysis results show the phase relationship between these summer teleconnections at quasi-4-year oscillation. The possible relation to ENSO cycle at such time scale has also been deduced.  相似文献   

北半球大气遥相关型与区域尺度大气扰动   总被引：4，自引：2，他引：2       下载免费PDF全文

钱维宏  梁浩原 《地球物理学报》2012,55(5):1449-1461

北极涛动(AO)、北大西洋涛动(NAO)和太平洋-北美型(PNA)等北半球大气遥相关型,可以用大气位势高度的物理分解扰动分量解释.结果发现,AO反映的是北极地区行星尺度纬圈平均扰动分量的变化,PNA与持续性天气尺度扰动分量相联系,NAO是行星尺度纬圈平均扰动与天气尺度扰动共同作用的结果.对行星尺度纬圈平均扰动分量和天气尺度扰动分量用旋转经验正交函数(REOF)展开,不但可以证实人们已经命名的区域性大气涛动,还新发现了北极地区的两对偶极涛动、欧亚涛动(EAO)和"大西洋-欧亚型"(AEA)波列.这些涛动连接了相邻地区的异常天气和异常气候.  相似文献   

ANALYSES OF THE DYNAMIC EFFECTS ON WINTER CIRCULATION OF THE TWO MAIN MOUNTAINS IN THE NORTHERN HEMISPHERE——Ⅰ.RELATIONSHIP AMONG GENERAL CIRCULATION,TELECONNECTION AND STATIONARY WAVES          下载免费PDF全文

邹晓蕾  叶笃正  吴国雄 《Acta Meteorologica Sinica》1992,(4)

The distribution of troughs and ridges of geopotential height,the teleconnection patterns and the propagation pat-terns of stationary waves are the main features of the January mean geopotential height field at 500hPa.Data analysesand numerical experiments indicate that these three characteristics are associated to one another and closely related tothe mechanical forcing of the Rocky Mountains and Tibetan Plateau.There exists a prominent negative correlation inthe intensity variation between the American trough and the Asian trough at high and middle latitudes.Such negativecorrelation,in connection with the interannual variation of the intensity of the jets in front of the two troughs,leads tothe existence of similar teleconnection patterns in North America and East Asia.On the other hand,the different propa-gation behaviour of quasi-stationary waves downstream of the two main mountains results in a fundamental differencein the distribution of correlation chains in North America and East Asia.  相似文献   

Initial tectonothermal evolution within the Scandinavian Caledonide Accretionary Prism: constraints from ⁴⁰Ar/³⁹Ar mineral ages within the Seve Nappe Complex, Sarek Mountains, Sweden     

R. D. DALLMEYER  P. G. ANDRÉASSON  O. SVENNINGSEN 《Journal of Metamorphic Geology》1991,9(2):203-218

In the Caledonide orogen of northern Sweden, the Seve Nappe Complex is dominated by rift facies sedimentary and mafic rocks derived from the Late Proterozoic Baltoscandian miogeocline and offshore-continent–Iapetus transition. Metamorphic breaks and structural inversions characterize the nappe complex. Within the Sarek Mountains, the Sarektjåkkå Nappe is composed of c. 600-Ma-old dolerites with subordinate screens of sedimentary rocks. These lithological elements preserve parageneses which record contact metamorphism at shallow crustal levels. The Sarektjåkkå Nappe is situated between eclogite-bearing nappes (Mikka and Tsäkkok nappes) which underwent high-P metamorphism at c. 500 Ma during westward subduction of the Baltoscandian margin. ⁴⁰Ar/³⁹Ar mineral ages of c. 520–500 Ma are recorded by hornblende within variably foliated amphibolite derived from mafic dyke protoliths within the Sarektjåkkå Nappe. Plateau ages of 500 Ma are displayed by muscovite within the basal thrust of the nappe and are consistent with metamorphic evidence which indicates that the nappe escaped crustal depression as a result of detachment at an early stage of subduction. Cooling ages recorded by hornblende from variably retrogressed eclogites in the entire region are in the range of c. 510–490 Ma and suggest that imbrication of the subducting miogeocline was followed by differential exhumation of the various imbricate sheets. Hornblende cooling ages of 470–460 Ma are recorded from massive dyke protoliths within the Sarektjåkkå Nappe. These are similar to ages reported from the Seve Nappe Complex in the central Scandinavian Caledonides. Probably these date imbrication and uplift related to Early Ordovician arrival of outboard terranes (e.g. island-arc sequences represented by structurally lower horizons of the Köli Nappes). Metamorphic contrasts and the distinct grouping of mineral cooling ages suggest that the various Seve structural units are themselves internally imbricated, and were individually tectonically uplifted through argon closure temperatures during assembly of the Seve Nappe Complex. The cooling ages of 520–500 Ma recorded within Seve terranes and along terrane boundaries of the Sarek Mountains provide evidence of significant accretionary activity in the northern Scandinavian Caledonides in the Late Cambrian–Early Ordovician.  相似文献   

Global surface temperature in relation to northeast monsoon rainfall over Tamil Nadu   总被引：3，自引：0，他引：3  

S. Balachandran  R. Asokan  S. Sridharan 《Journal of Earth System Science》2006,115(3):349-362

The local and teleconnective association between Northeast Monsoon Rainfall (NEMR) over Tamil Nadu and global Surface Temperature Anomalies (STA) is examined using the monthly gridded STA data for the period 1901–2004. Various geographical regions which have significant teleconnective signals associated with NEMR are identified. During excess (deficient) NEMR years, it is observed that the meridional gradient in surface air temperature anomalies between Europe and north Africa, in the month of September is directed from the subtropics (higher latitudes) to higher latitudes (subtropics). It is also observed that North Atlantic Oscillation (NAO) during September influences the surface air temperature distribution over north Africa and Europe. Also, the NAO index in January shows significant inverse relationship with NEMR since recent times. The central and eastern equatorial Pacific oceanic regions have significant and consistent positive correlation with NEMR while the western equatorial region has significant negative correlation with NEMR. A zonal temperature anomaly gradient index (ZTAGI) defined between eastern equatorial Pacific and western equatorial Pacific shows stable significant inverse relationship with NEMR  相似文献   

影响我国冬季温度的若干气候因子   总被引：23，自引：3，他引：23  

李勇  陆日宇  何金海 《大气科学》2007,31(3):505-514

综合分析了西伯利亚高压、北极涛动、ENSO和西太平洋遥相关型（WP）在年际和年代际时间尺度上对中国冬季温度的影响，结果表明在年际尺度上，WP和西伯利亚高压都对温度有显著影响，WP的影响主要存在于中国东部从东北南部至广东沿海一带大陆边缘区，而西伯利亚高压的影响范围则大得多，几乎涵盖了除黄河长江上游部分地区外的整个中国。在年代际尺度上，北极涛动和ENSO都与东亚冬季风有关联，北极涛动比ENSO的影响范围大，除长江上游沿江地区外的其他地区基本上都是关联区，ENSO与温度的关联区位于35°N以北的整个北方及长江中下游地区。  相似文献   

Teleconnection between Sea Ice in the Barents Sea in June and the Silk Road,Pacific–Japan and East Asian Rainfall Patterns in August   总被引：3，自引：0，他引：3  

Shengping HE  Yongqi GAO  Tore FUREVIK  Huijun WANG  Fei LI 《大气科学进展》2018,35(1):52-64

In contrast to previous studies that have tended to focus on the influence of the total Arctic sea-ice cover on the East Asian summer tripole rainfall pattern, the present study identifies the Barents Sea as the key region where the June sea-ice variability exerts the most significant impacts on the East Asian August tripole rainfall pattern, and explores the teleconnection mechanisms involved. The results reveal that a reduction in June sea ice excites anomalous upward air motion due to strong near-surface thermal forcing, which further triggers a meridional overturning wave-like pattern extending to midlatitudes.Anomalous downward motion therefore forms over the Caspian Sea, which in turn induces zonally oriented overturning circulation along the subtropical jet stream, exhibiting the east–west Rossby wave train known as the Silk Road pattern. It is suggested that the Bonin high, a subtropical anticyclone predominant near South Korea, shows a significant anomaly due to the eastward extension of the Silk Road pattern to East Asia. As a possible descending branch of the Hadley cell, the Bonin high anomaly ultimately triggers a meridional overturning, establishing the Pacific–Japan pattern. This in turn induces an anomalous anticyclone and cyclone pair over East Asia, and a tripole vertical convection anomaly meridionally oriented over East Asia. Consequently, a tripole rainfall anomaly pattern is observed over East Asia. Results from numerical experiments using version 5 of the Community Atmosphere Model support the interpretation of this chain of events.  相似文献   

Modoki对南半球中高纬度气候及海冰异常的影响     

袁博仑  潘增弟  刘娜  陈红霞 《海洋学报》2014,36(3):104-112

利用诊断分析方法分析研究了热带太平洋ENSO Modoki现象对南半球中高纬度气候和海冰的影响。分析了ENSO Modoki现象的季节变化特征,并定义了ENSO Modoki的活跃年和活跃季节。利用偏相关分析、合成分析和超前滞后相关分析等诊断分析方法,分析了1979年1月到2010年12月间ENSO Modoki影响南半球中高纬气候及海冰异常的遥相关模态及可能的遥相关动力机制。研究结果显示费雷尔环流的异常变化是两者之间遥相关的可能方式。  相似文献   

秋季南极涛动异常对冬季中国南方降水的影响   总被引：2，自引：0，他引：2  

钱卓蕾 《大气科学》2014,38(1):190-200

本文针对秋季南极涛动（AAO）和冬季中国南方降水的关系作了研究,发现两者之间存在显著的反向年际变化关系。AAO正（负）异常年,副热带西风急流显著增强（减弱）,欧洲西部槽、乌拉尔山高压脊和东亚沿岸大槽均偏强（偏弱）,阿留申低压、南支槽和西太平洋副高偏弱（偏强）,西南急流上的扰动不活跃（活跃）,我国大部分地区出现异常偏北风（偏南风）和OLR弱正距平,导致南方降水偏少（偏多）。两半球存在东亚—南半球高纬地区和纵贯太平洋南北的两个遥相关型,海洋性大陆对流活动可能是秋季AAO影响南方冬季降水的一个机制。因此,秋季南极涛动的异常很可能对预测我国南方冬季降水有显著指示意义。  相似文献   

陕西盛夏极端降水频次及其与全球海温的遥相关研究     

程肖侠  方建刚  雷向杰 《干旱气象》2014,(1):38-45

基于陕西省78个测站1961~2011年盛夏逐日降水量资料以及NOAA全球2°×2°海温场资料,分析了陕西盛夏极端降水事件气候特征及其与海温场的遥相关关系。结果表明:(1)盛夏,陕西南部、关中西部及陕北南部是极端降水事件高发区;(2)近年来盛夏极端降水事件呈上升趋势,1976年后显著上升;(3)极端降水事件与前期海温场具有较好的遥相关关系,与同期(同月)海温场相关性不显著;(4)上年秋季、冬季赤道中东太平洋和上年秋季阿拉伯海海温异常偏暖,赤道中东太平洋南北两侧海温偏冷,以及前期2月印度洋和中国近海海温异常偏暖,关中中东部及陕南中东部局地7月极端降水偏多,反之亦然;上年秋季印度洋和赤道东太平洋、上年冬季及当年春季印度洋西部海温异常偏暖,关中中西部地区8月极端降水偏多,反之亦然。  相似文献