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1.
Interannual Relationship between the Winter Aleutian Low and Rainfall in the Following Summer in South China 
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下载免费PDF全文 Using observations and reanalysis data, this study investigates the interannual relationship between the winter Aleutian Low(AL) and the rainfall anomalies in the following summer in South China(SC). Results show that the winter AL is significantly positively(negatively) correlated with the SC rainfall anomalies in the following July(August). Specifically, SC rainfall anomalies have a tendency to be positive(negative) in July(August) when the preceding winter AL is stronger than normal. The winter AL-related atmospheric circulation anomalies in the following summer are also examined. When the winter AL is stronger, there is a significant anticyclonic(cyclonic) circulation anomaly over the subtropical western North Pacific in the following July(August). Southerly(northerly) wind anomalies to the west of this anomalous anticyclonic(cyclonic) circulation increase(decrease) the northward moisture transportation and contribute to the positive(negative) rainfall anomalies over SC in July(August). This study indicates that the AL in the preceding winter can be used as a potential predictor of the rainfall anomalies in the following July and August over SC. 相似文献
2.
The aim of this paper is to investigate different aspects of the seasonal-to-interannual temperature variability in Eastern Patagonia, the southernmost area of South America, east of the Andes Cordillera. Homogenous regions of seasonal variability and the atmospheric circulation patterns associated with warm and cold conditions in each of them are described in this study. Relationships between temperature in Eastern Patagonia and that registered in other areas of southern South America are also addressed. Results show that the northern and southern areas of Eastern Patagonia have different temperature variability in summer and autumn whereas the temperature variability tends to be more homogeneous within the region during winter and spring. Warm (cold) conditions in the northern areas are associated with reinforced (weakened) westerlies in summer, winter and spring whereas northerly (southerly) advections of warm (cold) air toward the region produce such conditions in autumn. Temperature in the southern portion of Eastern Patagonia is affected by anticyclonic (cyclonic) anomalies that enhance (reduce) the incoming solar radiation and induce reinforced (weakened) westerlies promoting warm (cold) conditions in the region. Furthermore, cyclonic (anticyclonic) anomalies at subpolar latitudes hinder (favor) outbreaks of cold air increasing (decreasing) the temperature over areas of Eastern Patagonia. The circulation anomalies associated with warm (cold) conditions in Eastern Patagonia also promote cold (warm) conditions over areas of northern Argentina, Paraguay and southern Brazil. Consequently, a dipole of temperature is detected in southern South America with centers of opposite sign over these regions. 相似文献
3.
从2011/2012和2015/2016年冬季大气环流异常看北极海冰以及前期夏季北极大气环流异常的作用 总被引：1，自引：0，他引：1
利用美国NCEP/NCAR、欧洲中心ERA-Interim再分析资料,以及英国哈得来中心海冰密集度资料,通过诊断分析和数值模拟试验,研究了2011/2012和2015/2016年两个冬季大气环流异常的主要特征和可能原因。结果表明,尽管热带太平洋海温背景截然不同（分别为弱的拉尼娜事件和强厄尔尼诺事件）,但这两个冬季西伯利亚高压均异常偏强,自1979年以来其强度分别排第1和第5位。前期秋季北极海冰异常偏少是导致这两个冬季西伯利亚高压偏强的主要原因。更为重要的是,前期夏季北冰洋表面反气旋风场,以及其上空对流层中、低层平均气温偏高,加强了北极海冰偏少对冬季大气变率的负反馈,进一步促进了西伯利亚高压的加强,从而有利于东亚地区冬季阶段性强严寒的出现。因此,夏季北极大气环流的动力和热力状态不仅影响夏、秋季北极海冰,而且对海冰偏少影响亚洲冬季气候变率有重要调节作用。2015/2016年冬季强厄尔尼诺事件并不能掩盖来自北极海冰和大气环流的影响。 相似文献
4.
Christos H. Halios Costas G. Helmis Helena A. Flocas Stephan Nyeki Dimosthenis N. Assimakopoulos 《Meteorology and Atmospheric Physics》2012,118(3-4):107-115
Synoptic climatology relates the atmospheric circulation with the surface environment. The aim of this study is to examine the variability of the surface meteorological patterns, which are developing under different synoptic scale categories over a suburban area with complex topography. Multivariate Data Analysis techniques were performed to a data set with surface meteorological elements. Three principal components related to the thermodynamic status of the surface environment and the two components of the wind speed were found. The variability of the surface flows was related with atmospheric circulation categories by applying Correspondence Analysis. Similar surface thermodynamic fields develop under cyclonic categories, which are contrasted with the anti-cyclonic category. A strong, steady wind flow characterized by high shear values develops under the cyclonic Closed Low and the anticyclonic H–L categories, in contrast to the variable weak flow under the anticyclonic Open Anticyclone category. 相似文献
5.
Influence of North Atlantic sea surface temperature (SST) anomalies on tropical Pacific SST anomalies is examined. Both summer and winter North Atlantic SST anomalies are negatively related to central-eastern tropical Pacific SST anomalies in the subsequent months varying from 5 to 13?months. In particular, when the North Atlantic is colder than normal in the summer, an El Ni?o event is likely to be initiated in the subsequent spring in the tropical Pacific. Associated with summer cold North Atlantic SST anomalies is an anomalous cyclonic circulation at low-level over the North Atlantic from subsequent October to April. Corresponded to this local response, an SST-induced heating over the North Atlantic produces a teleconnected pattern, similar to the East Atlantic/West Russia teleconnection. The pattern features two anticyclonic circulations near England and Lake Baikal, and two cyclonic circulations over the North Atlantic and near the Caspian Sea. The anticyclonic circulation near Lake Baikal enhances the continent northerlies, and strengthens the East-Asian winter monsoon. These are also associated with an off-equatorial cyclonic circulation in the western Pacific during the subsequent winter and spring, which produces equatorial westerly wind anomalies in the western Pacific. The equatorial westerly wind anomalies in the winter and spring can help initiate a Pacific El Ni?o event following a cold North Atlantic in the summer. 相似文献
6.
Conventional average values of Wallace-Gutzler indices for the regional circulations and average values of major variability
components of the fields of the North Atlantic surface temperature anomalies are plotted on the geographical map used to analyze
the total daily precipitation fields. The computation conditions of average values are defined by the dates classified according
to three equiprobable gradations of total precipitation. A projection of conditional average values to the precipitation field
points enables to estimate the atmospheric and oceanic “tracks” within the marked out gradations of total precipitation. The
stratification and computation of characteristics are carried out for the summer and winter seasons. Large regions are revealed
of statistically significant interrelation of the atmospheric circulation and major components of variability of the sea surface
temperature anomalies with the extreme gradations of total precipitation for summer and winter seasons. The recommendations
are formulated for the use of obtained results in the practice of the seasonal forecasting of meteorological conditions. 相似文献
7.
冬季热带西太平洋海平面气压与后期亚洲夏季风的关系 总被引：1，自引：0，他引：1
利用月平均的NCEP/NCAR再分析资料(1958-1996),基于一个新的冬季热带西太平区域环流指数,研究了冬季热带西太平洋环流的极端异常及其随时间的演变。研究发现,冬季热带西太平洋环流异常与北半球亚洲大陆高纬度地区的气候变化有紧密的联系。随着季节发展,冬季出现在热带西太平洋的一个反气旋(气旋)环流异常逐渐向东北方向移动并向西扩展,其东西方向的轴线逐渐被拉长。因此,位于反气旋(气旋)环流异常南部的异常东风(西风)连续向西伸展到印度半岛,导致南亚夏季风减弱(增强)。同时,随着季节发展,源于热带西太平洋的气压异常逐渐移近并最终占据亚洲大陆,进而影响夏季亚洲大陆热低压。 相似文献
8.
Effects of atmosphere-ocean interaction on the interannual variability of winter temperature in Taiwan and East Asia 总被引：1，自引：0，他引：1
This study investigated the ocean-atmosphere interaction effect on the winter surface air temperature in Taiwan. Temperature
fluctuations in Taiwan and marine East Asia correlated better with a SST dipole in the western North Pacific than the SST
in the central/eastern equatorial Pacific. During the warm (cold) winters, a positive (negative) SST anomaly appears in marine
East Asia and a negative (positive) SST anomaly appears in the Philippine Sea. The corresponding low-level atmospheric circulation
is a cyclonic (anticyclonic) anomaly over the East Asian continent and an anticyclonic (cyclonic) circulation in the Philippine
Sea during the warm (cold) winters. Based on the results of both numerical and empirical studies, it is proposed that a vigorous
ocean-atmosphere interaction occurring in the western North Pacific modulates the strength of the East Asian winter monsoon
and the winter temperature in marine East Asia. The mechanism is described as follows. The near-surface circulation anomalies,
which are forced by the local SST anomaly, strengthen (weaken) the northeasterly trade winds in the Philippine Sea and weaken
(strengthen) the northeasterly winter monsoon in East Asia during warm (cold) winters. The anomalous circulation causes the
SST to fluctuate by modulating the heat flux at the ocean surface. The SST anomaly in turn enhances the anomalous circulation.
Such an ocean-atmosphere interaction results in the rapid development of the anomalous circulation in the western North Pacific
and the anomalous winter temperature in marine East Asia. This interaction is phase-locked with the seasonal cycle and occurs
most efficiently in the boreal winters.
Received: 22 October 1999 / Accepted: 5 June 2000 相似文献
9.
我国西南地区秋季降水年际变化的空间差异及其成因 总被引：3，自引：0，他引：3
使用1980～2010年全国站点降水资料、ERA-Interim再分析环流资料、哈德莱海表温度资料,运用聚类分析和旋转经验正交函数分解,对西南地区的秋季降水按照其年际变化规律进行分区,进而分析影响各区域降水变化的物理过程和机理。结果表明:西南地区被分为东、西两个区域。西南东、西区域秋季降水的年际变化、显著周期、旱涝异常年份、相关的环流系统都有明显差异。西南东部秋季降水主要与热带海温异常有关,受低纬度环流影响。当赤道东太平洋为暖海温异常,热带印度洋为西正东负的偶极子型海温异常时,分别激发出西北太平洋反气旋和孟加拉反气旋,共同向西南东部输送水汽,造成西南东部降水偏多。西南西部降水在秋季三个月份与不同的环流形势对应:9月降水由中南半岛反气旋输送的暖湿气流决定;10月降水受高原以东反气旋环流和孟加拉湾低槽共同影响;11月降水主要受中高纬环流异常的影响,与斯堪的纳维亚遥相关存在显著负相关。 相似文献
10.
Juan Andrés García-Valero Juan Pedro Montavez Sonia Jerez Juan José Gómez-Navarro Raquel Lorente-Plazas Pedro Jiménez-Guerrero 《Theoretical and Applied Climatology》2012,110(1-2):291-310
A seasonal analysis of the atmospheric circulation over the Iberian Peninsula (IP) based on circulation types (CTs) obtained from sea level pressure and 500-hPa geopotential height is presented. The study covers the period of 1958–2008, when a high variability and important changes in winter and spring precipitation and temperature have been reported. Frequency, persistence, and the most probable transitions of the circulation types are analyzed. Among the clustering methods available in the literature, two of the most reliable classification methods have been tested, K-means and simulated annealing and diversified randomization. A comparison of both methods over the IP is presented for winter (DJF). The quality of the circulation types obtained through both methods as well as the better stability achieved by K-means suggest this method as more appropriated for our target area. Twelve CTs were obtained for each season and were analyzed. The patterns obtained were regrouped in five general situations: anticyclonic, cyclonic, zonal, summertime, and hybrid-mixed. The analysis of frequencies of these situations offers a similar characterization of the atmospheric circulation that others previously obtained by subjective methods. The analysis of the trends in frequency and persistence for each CT shows few significant trends, mainly in winter and spring with a general decrease of the cyclonic patterns and an increase of the anticyclonic situations. This can be related to the negative precipitation trends reported by other authors. Regarding the persistence, an interesting result is that there is a high interannual variability of the persistence in autumn and spring, when patterns can persist longer than in other seasons. An analysis of the most probable transitions between the CTs has been performed, revealing the existence of cyclic sequences in all seasons. These sequences are related to the high frequency of certain patterns such as the anticyclonic situations in winter. Finally, a clear seasonal dependence of the transitions between cyclonic situations associated with extratropical disturbances was found. This dependence suggests that the transitions of low-pressure systems towards the south of the IP are more likely in spring and autumn than in winter. 相似文献
11.
This study investigates the circulation and precipitation anomalies associated with different configurations of the western North Pacific subtropical high(WNPSH) and the East Asian westerly jet(EAJ) in summer on interannual timescales. The in-phase configuration of the WNPSH and EAJ is characterized by the westward(eastward) extension of the WNPSH and the southward(northward) shift of the EAJ, which is consistent with the general correspondence between their variations. The out-of-phase configuration includes the residual cases. We find that the in-phase configuration manifests itself as a typical meridional teleconnection. For instance, there is an anticyclonic(cyclonic) anomaly over the tropical western North Pacific and a cyclonic(anticyclonic) anomaly over the mid-latitudes of East Asia in the lower troposphere. These circulation anomalies are more conducive to rainfall anomalies over the Yangtze River basin and south Japan than are the individual WNPSH or EAJ. By contrast, for the out-of-phase configuration, the mid-latitude cyclonic(anticyclonic) anomaly is absent, and the lower-tropospheric circulation anomalies feature an anticyclonic(cyclonic)anomaly with a large meridional extension. Correspondingly, significant rainfall anomalies move northward to North China and the northern Korean Peninsula. Further results indicate that the out-of-phase configuration is associated with the developing phase of ENSO, with strong and significant sea surface temperature(SST) anomalies in the tropical central and eastern Pacific which occur simultaneously during summer and persist into the following winter. This is sharply different from the in-phase configuration, for which the tropical SSTs are not a necessity. 相似文献
12.
C. Michailidou P. Maheras A. Arseni-Papadimititriou F. Kolyva-Machera C. Anagnostopoulou 《Theoretical and Applied Climatology》2009,97(1-2):163-177
This paper presents a method for grouping weather types that occur over an area, which combines meteorological parameters, reflecting air mass characteristics at the surface, with synoptic conditions prevailing over an area. Five quantitative meteorological parameters are used in the procedure: temperature, precipitation, relative humidity, wind velocity and sunshine duration. In addition, two qualitative variables related to the prevailing circulation type and whether it is cyclonic or anticyclonic are also included. The study period is 43 years (1958–2000) and is restricted to the cold and wet sub-period of the year, December–March. Weather types are defined using a relatively new method of cluster analysis, two-step cluster analysis, which allows the simultaneous use of both quantitative and qualitative variables. The aim of the present study is to distinguish primary weather patterns so that the investigation into the relationship between weather patterns and circulation types will be more effective. For Athens, six weather types are created, whereas for Thessaloniki five are produced. For both stations, only two weather types are related to anticyclonic situations. The majority of the identified weather types correspond to a distinctive and well-defined synoptic situation. Each weather type differs from the others, not only in terms of the circulation conditions referring to it, but also with reference to meteorological variables such as temperature and precipitation. The results of the evaluation of the aforementioned procedure are considered to be highly satisfactory. 相似文献
13.
Monthly mean surface pressure patterns in the European area are reconstructed for those winter and summer seasons of the 16th century with outstanding climatic anomalies being either widespread over Europe or remarkably intensive in some European regions. From the available documentary information about weather characteristics and their sequences, it proved possible to infer prevalent processes of lower tropospheric advection of typical air masses and to assess the position and strength of major surface pressure centres on a monthly scale. For comparison with modern pressure patterns, monthly mean sea level pressure (SLP) grids from the 20th century have been selected for seasons with similar climatic anomalies. There are broad coincidences between these pressure patterns of the 16th and the 20th centuries except for cold summer seasons. Finally, results from the 16th century are discussed in terms of circulation dynamics (different phases of the North Atlantic Oscillation (NAO) in winter, decreasing frequency of anticyclonic ridging in summer). 相似文献
14.
Changes in atmospheric circulation over Europe detected by objective and subjective methods 总被引：1，自引：0，他引：1
Summary Changes in atmospheric circulation over Europe since 1958 were examined using both objective (modes of low-frequency variability
and objective classification of circulation types) and subjective (Hess-Brezowsky classification of weather types) methods.
The analysis was performed with an emphasis on the differences between the winter (DJF) and summer (JJA) seasons, and between
objectively and subjectively based results. Majority of the most important changes in atmospheric circulation are same or
similar for the objective and subjective methods: they include the strengthening of the zonal flow in winter since the 1960s
to the early 1990s; the increase (decrease) in frequency of anticyclonic (cyclonic) types in winter from the late 1960s to
the early 1990s, with a subsequent decline (rise); and the sharp increase in the persistence (measured by the mean residence
time) of all groups of circulation types in winter around 1990 and of anticyclonic types in summer during the 1990s. Differences
between the findings obtained using the objective and subjective methods may result from the intrinsically different approach
to the classification (e.g. the Hess-Brezowsky weather types have a typical duration of at least 3 days while objective types
typically last 1–3 days). Generally, changes in atmospheric circulation which have taken place since the 1960s were more pronounced
in winter than in summer. The most conspicuous change seems to be the considerable increase in the persistence of circulation
types during the 1990s, which may be also reflected in the increase in the occurrence of climatic extremes observed in Europe
during recent years. 相似文献
15.
韵律与长期天气预报 总被引：4，自引：1，他引：4
本文讨论了对长期天气预报比较重要的韵律问题,共有三部分内容:(1)分析广大台站在相关普查中发现的隔季相关现象,相关间隔自2个月到11个月不等,其中大约半年左右的比较常见,并且地理分布区域性强,大洋上最明显,指出这是韵律现象。 (2)月平均环流与海温的相似性分析表明,北半球环流与海温都存在着隔季相似性。例如,春或夏海温距平相似时,大约6个月之后又相似。而秋冬春三季大气环流的相似容易造成夏季大气环流的相似。指出这是大气环流与海洋的韵律活动的表现。 (3)讨论了两种可能的韵律形成过程,一种是北太平洋西风漂流区夏季海温通过韵律关系影响半年后的冬季海温,从而影响大气环流和天气。另一种是冬季低纬东太平洋海温与大气环流相互作用,通过韵律关系影响半年之后夏季低纬太平洋的环流,从而影响西太平洋副高及我国天气。 相似文献
16.
Anthropogenic aerosols (AA) have significantly caused anomalous winter mean atmospheric circulation over the Northern Hemisphere, but the main daily patterns of winter large-scale circulation change are not well understood. Here a self-organizing map analysis is applied to identify the leading patterns in AA-induced winter daily geopotential height (Z) anomaly fields simulated by three atmospheric general circulation models, with a focus on fast adjustments. Two winter daily circulation response patterns with a synoptic time scale are found: one pattern shows concurring Z anomalies over North America and North Asia with the same sign and the Bering Sea seeing the opposite, resembling the Asia–Bering–North American teleconnection; while the other is the Arctic Oscillation-like pattern with similar Z anomalies over North Pacific and North Atlantic and the opposite over the Arctic region. The AA-induced anomalous precipitation over the tropics and anomalous synoptic eddy activities over the extratropical oceans concur to support and maintain these circulation anomaly patterns. The winter-mean climate responses to AA can be understood as a result of these daily anomaly patterns, especially over the higher latitudes. Specifically, the associated changes in surface air temperature (SAT) over the mid-high latitudes are caused by the AA-driven meridional movements of polar (cold and dry) airmass and midlatitude (warm and moist) airmass in the regions, mainly through the relevant surface downward longwave radiation. This study highlights the role of AA in altering daily weather patterns, which is not sufficiently captured by seasonal mean responses. 相似文献
17.
我国华南3月份降水异常的可能影响因子分析 总被引：4，自引：3，他引：1
利用1951～2005年华南地区3月份的降水资料、NOAA海温资料、Ni?o3.4指数和NCEP再分析资料,分析了华南3月份降水异常与同期环流场、全球海温场的关系,从环流和海温的角度揭示了华南3月份降水异常的可能原因。结果表明,当华南3月份降水偏多(少)时,在对流层中低层,北太平洋海区存在气旋(反气旋)性环流异常,西太平洋及南海海面上存在反气旋(气旋)性环流异常,这样的环流异常有利(不利)于东南暖湿气流与北方东部异常冷空气在华南地区形成水汽辐合,导致降水显著增多(减少)。进一步的分析表明,ENSO和北印度洋及南海附近海温是影响华南3月份降水异常的重要外强迫因子,ENSO对华南3月降水异常的影响是通过影响春季西太平洋副热带高压和低层风场异常实现的,而北印度洋及南海附近海温对华南3月降水异常的影响则是通过垂直环流场异常和低层风场以及西太平洋副热带高压异常来实现的。 相似文献
18.
Changes of atmospheric circulation in central Europe and their influence on climatic trends in the Czech Republic 总被引：1，自引：1，他引：0
This work deals with the influence of changes of atmospheric circulation on observed trends of 11 climatic elements at 21 stations in the Czech Republic in the period 1961–1998. Atmospheric circulation in central Europe is described by the German (Hess-Brezowsky) and Czech-Slovak (Brádka’s) subjective catalogues of synoptic types. In the study period there is a strong downward trend in the occurrence of anticyclonic types in Brádka’s catalogue in all seasons, this trend being most prominent in autumn. Westerly and northwesterly types become more frequent in autumn and winter, less frequent in spring and summer under both classifications. In the Hess-Brezowsky catalogue, the occurrence of anticyclonic types increases in winter, spring, and summer. To assess the effect of circulation changes on observed climate trends we have used the method of “hypothetical” seasonal trends that are calculated from a daily series, constructed by assigning the long-term monthly average of the given climatic element under a specific circulation type to each day classified with this type. The ratio of these circulation-conditioned trends and observed seasonal trends shows that changes in atmospheric circulation are the primary cause of massive winter warming and autumn cooling, which is connected with increasing precipitation and humidity. Summer climate trends are unrelated to changes in atmospheric circulation. Simultaneous use of more circulation classifications for the detection of climatic changes is highly recommended, as the long-term circulation trends depend on the catalogue applied. 相似文献
19.
我国四季极端雨日数时空变化及其与海表温度异常的关系 总被引：3，自引：0，他引：3
利用1960—2004年我国586个气象站的逐日降水观测资料,对每个季节和每个站点,以雨日降水量升序排列的第90个百分位值定义极端日降水阈值,分析揭示了我国四季极端雨日数的时空变化特征、与海表温度异常的关系以及相联系的大气环流异常型。结果表明,我国长江流域极端雨日数在冬季和夏季呈显著增加趋势,华北地区极端雨日数在冬季显著增加、而在夏季显著减少,华南地区极端雨日数在春季显著增加,东北地区极端雨日数在冬季和春季显著增加,而西北地区极端雨日数在四季均显著增加。各季极端雨日数在线性趋势变化之上表现年际和年代际变化特征,并且其典型异常型明显不同,春、秋季表现为长江以南与以北地区反位相的"偶极型"变化,夏季表现为长江流域与华南、华北地区反位相的"三极型"变化,冬季表现为全国大部分地区同位相的"单极型"变化。我国季节极端雨日数与印度洋-太平洋海表温度异常的关系主要表现为与ENSO的关系,而ENSO影响我国极端降水异常是通过相应的大气环流异常型来实现的。 相似文献
20.
利用中国东北地区1981—2018年166个地面气象观测站资料, 定义了中国东北地区秋冬季霾日指数, 分析了年际尺度上该地区霾日数与同期大气环流异常的内在关系。结果表明: 中国东北地区秋冬季霾日指数存在显著的年际变化特征, 欧亚—太平洋遥相关型(Eurasia-Pacific Teleconnection Pattern, EUP)负位相、东亚大槽偏弱等大气环流异常配置导致中国东北地区秋冬季霾的发生频次增加。巴伦支海与喀拉海北部海域是影响中国东北地区秋冬季霾日年际变化的海冰关键区, 该区域海冰面积与霾日数呈显著负相关, 北极海冰通过改变大气环流间接影响中国东北地区秋冬季霾日发生频次, 当北极海冰异常偏少时, 东亚冬季风偏弱, 近地面风速偏低, 环境湿度偏高, 中国东北地区受东北亚异常反气旋西侧的异常偏南风控制, 且受“EUP”负位相模态影响, 东亚大槽减弱, 有利于大气污染物和水汽向中国东北地区输送, 该地区秋冬季霾的发生频次增加。 相似文献