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1.
华西秋雨准4年周期特征及其与赤道太平洋海表温度的关系 总被引：6，自引：0，他引：6
利用1959～2011年华西地区气象台站资料、NCEP/NCAR再分析资料、NOAA海表温度资料, 采用多锥度—奇异值分解(MTM-SVD)方法, 研究了华西秋雨的准4年周期特征及其与赤道太平洋海表温度的协同变化关系。研究结果表明:华西秋雨具有显著的准4年周期, 其典型循环表现为"偏强, 略偏强, 偏弱, 略偏弱"的特点。在准4年周期上赤道中太平洋海表温度对华西秋雨的协同变化表现为"偏低, 略偏低, 偏高, 略偏高", 这种协同变化从初夏就体现出来, 并一直持续到秋末。同时在准4年周期上, 华西秋雨对ENSO事件也存在一定的响应, 但是主要体现在发生强ENSO事件时。准4年周期的环流分析表明, 夏季到秋季赤道中太平洋海表温度偏低(高)时, 秋季500 hPa高度场出现东亚/太平洋(EAP)遥相关波列正(负)异常, 西太平洋副热带高压偏西(东), 华西地区来自南海西太平洋和孟加拉的水汽输送偏多(少), 华西秋雨偏强(弱)。 相似文献
2.
利用1960-2006年NCEP/NCAR逐月再分析资料、NOAA月平均海表温度资料和湖南月降水资料等,在计算分析湖南主汛期旱涝变化特征的基础上,对湖南主汛期旱涝大气环流及其与春季海温的关系进行了分析。结果表明,湖南主汛期洪涝指数增大趋势显著,1990年代以来处于洪涝多发期。洪涝指数具有20年、9年和3~4年的周期;干旱指数存在22年、10年和2~4年周期。湖南主汛期旱涝与西太平洋副热带高压、中高纬度环流、南亚高压、低层流场、水汽输送等持续异常有关。当西太平洋副热带高压面积偏大,强度偏强,脊线偏南,西伸脊点偏西,鄂霍次克海地区多阻塞活动,南亚高压主体位置较常年偏西,来自南海的水汽输送较常年强,低层湖南大部分地区处于辐合气流控制之下,湖南主汛期易洪涝;反之,当西太平洋副热带高压面积偏小,强度偏弱,脊线偏北,西伸脊点偏东,鄂霍次克海地区少阻塞活动,南亚高压主体位置较常年偏东,来自南海的水汽输送较常年弱,低层湖南大部分地区为辐散气流控制,湖南主汛期易干旱。春季印度洋、赤道中东太平洋和黑潮海温是湖南主汛期旱涝变化的重要短期气候预测信号,春季印度洋和赤道中东太平洋海温偏高(低)有利于湖南主汛期降水偏多(少),黑潮海温偏低湖南主汛期易少雨干旱。 相似文献
3.
4.
利用河北省及邻近区域73个气象站1961—2009年逐年降水资料,同期NCEP/NCAR再分析资料,NOAA太平洋海温等资料,分析了河北省干旱的时空变化特征,并应用奇异值分解、合成分析等方法,研究了河北省典型旱涝年份与同期太平洋海温场和环流场的异常特征.结果表明：河北省旱涝异常的空间型分布主要有2种,这些空间型的时间变化除了具有明显的年际变化外,还存在显著的年代际变化.SVD（奇异值分解）分析揭示的河北省旱涝和海气异常的关系表明,当赤道东太平洋年平均海温异常偏低,北太平洋海盆中部年平均海温异常偏高的年份,河北省大部分地区容易偏涝,反之,易干旱.典型干旱年,500 hPa平均高度场上贝加尔湖西南部以及极地500 hPa年平均高度场为正异常,阿留申地区南部为负异常;亚洲中高纬地区环流从西到东呈现-+-的环流异常纬向分布.而典型雨涝年500 hPa平均高度场上贝加尔湖西南部以及极地500 hPa年平均高度场为负异常,阿留申地区南部为正异常;亚洲中高纬地区环流从西到东呈现-+的环流异常纬向分布. 相似文献
5.
利用欧洲中心１９８０～１９８９年逐日２００ｈＰａ、８５０ｈＰａ风场及日本气象研究所提供的ＧＭＳ观测的ＴＢＢ逐日资料,探讨了夏季东亚热带、副热带季风的强弱对中国东部夏季降水的影响．指出东亚夏季风系统中的两条辐合带热带辐合带（热带季风槽）和副热带辐合带（副热带梅雨锋）的强度的变化呈相反趋势,即热带季风槽偏弱时（弱季风）,副热带梅雨锋偏强;反之热带季风槽偏强时（强季风）,副热带梅雨锋偏弱．江淮流域的降水与热带季风槽、副热带梅雨锋的强度密切相关,即热带季风槽偏弱（弱季风）,梅雨锋偏强时,江淮流域的降水偏多;热带季风槽偏强（强季风）,梅雨锋偏弱时,江淮流域的降水偏少．研究表明：热带季风槽和副热带梅雨锋的强度与偏西气流的加强密切相关．当赤道东太平洋海温偏高,赤道西太平洋海温偏低,黑潮地区的海温偏高时,赤道东西太平洋上空的Ｗａｌｋｅｒ环流和西太平洋中纬度Ｈａｄｌｅｙ环流的下沉支气流减弱,东亚季风槽较弱（弱季风）,梅雨锋较强;当赤道东太平洋海温偏低、西太平洋海温偏高,黑潮地区的海温偏低时,赤道东西太平洋上空的Ｗａｌｋｅｒ环流和西太平洋中纬度Ｈａｄｌｅｙ环流的下沉支气流加强,东亚季风槽较强（强季风）,梅雨锋较弱． 相似文献
6.
利用1961-2009年NCEP/NCAR再分析资料及ERSST-v3海温资料,研究了湘中雨季结束日期的变化特征及其与前期大气环流和海温的关系.结果表明,近49 a湘中雨季结束日期具有较显著的年际和年代际变化特征,呈2.6天/10a的较显著变晚趋势.湘中雨季结束偏早(晚)年在大气环流上的前兆信号表现为前期冬春季北半球副热带高压、鄂霍茨克海高压和阿留申低压强度弱(强),东亚大槽较浅(深),冷空气活动偏弱(强).前期冬春季中东赤道及以北太平洋和印度洋海温异常是湘中雨季结束的重要短期气候预测信号,前期冬春季赤道中东太平洋、印度洋区域海温偏低(高),北太平洋区域海温偏高(低),湘中雨季结束日期偏早(晚). 相似文献
7.
本文分析了近几十年谷物产量和百余年海平面气压场及降水资料。揭示我国东部长江下游粮产区的天气和谷物天气产量存在30—40年的长周期振动和2—3年的短周期振动,并且与特定的相一致的大型环流系统振动相配合。通过分析讨论,提出了一个“环流一天气一天气产量”同步振动模式。简言之,即当冬季贝加尔湖冷高压偏弱和澳洲低压偏强,相应地,春季赤道低压偏强以及夏季南方涛动偏强时,则长江下游处于(长周期振动的)多水期或(短周期振动的)多水年型,谷物天气产量偏低。反之,则处于少水期或少水年型,谷物天气产量偏高。 相似文献
8.
夏季气候异常的前期信号特征分析一直是短期气候预测工作的重点。利用1948—2004年NCEP/NCAR月平均再分析资料、1961—2004年云南124个站的月平均降水和1948—2003年英国Hadley中心的月平均海温资料, 分析了云南夏季旱涝的时空特征, 探讨了云南夏季旱涝与前期大气环流和大气热力状态变化的关系, 发现云南夏季旱涝前冬12月—1月, 特别是1月东亚中高纬度地区的大气环流变化和赤道附近高低层大气的热力状态对云南夏季旱涝有重要的指示意义, 当前冬东亚大槽强 (弱), 冬季风强 (弱), 赤道附近高低层大气温度偏低 (高) 时, 后期云南夏季降水偏多 (少)。同时, 初步探讨了东亚冬夏季风环流变化的相互联系及热带海温变化的可能影响, 指出冬季到夏季印度洋和赤道西太平洋地区持续的海温异常有可能通过改变夏季海陆的热力对比, 进而影响夏季风活动和云南夏季降水的变化。 相似文献
9.
我国华南3月份降水年代际变化的特征 总被引：5，自引：2，他引：3
利用1951～2005年华南3月份降水资料、太平洋年代际振荡(PDO)指数以及NCEP再分析资料,对华南3月份降水年代际变化特征、及其对应的大尺度环流以及与PDO的关系进行了分析。结果表明,华南3月份降水存在显著的年代际变化特征,并且Mann-Kendal突变检验表明华南3月份降水在1978年左右发生年代际突变,从之前的降水偏少转变为降水偏多。我国华南3月份降水与PDO有着显著的相关。进一步研究表明,在年代际降水偏少时期,PDO处于负位相(北太平洋海温偏高,中东太平洋海温偏低),北太平洋海平面气压场和高度场偏高,亚洲大陆海平面气压场和高度场偏低,赤道西太平洋到赤道东印度洋附近的海平面气压场偏低,赤道辐合带附近地区的高度场偏低,东亚对流层大气偏暖,西太平洋副热带高压偏东,东亚高空急流偏北,东亚Hadley环流偏弱。在年代际降水偏多时期,PDO处于正位相,情况则与降水偏少时期相反。 相似文献
10.
本文分析了我国华南水稻天气产量、降水天气、大型气压环流三者的联系。揭示了“环流—天气—天气产量”具有20—30年左右的长周期振动和2—3年的短周期振动。长期振动模式描述为,北半球春季由太平洋赤道低压带与澳洲附近高压带组合的“南方涛动”偏弱时,相应地,夏季北太平洋高压偏强,华南处于多水期。水稻天气产量偏低。反之,华南处于少水期,水稻天气产量偏高。 相似文献
11.
Interdecadal variability of the relationship between the East Asian winter monsoon and ENSO 总被引：2，自引：0，他引：2
W. Zhou X. Wang T. J. Zhou C. Li J. C. L. Chan 《Meteorology and Atmospheric Physics》2007,98(3-4):283-293
Summary The authors examine relationships between the East Asian winter monsoon and the ENSO, particularly on the interdecadal timescales.
Based on the analyses of SLP data from 1899 to 1997, the East-Asian winter monsoon index (WMI) is defined as the zonal difference
of SLP between ∼120° E and ∼160° E. It is found that 18 out of 28 strong winter monsoon years are either before the development
of an El Ni?o or during the decaying La Ni?a event, 12 out of 28 weak winter monsoon are before the development of a La Ni?a
or during the decaying El Ni?o event. There is a significant positive correlation coefficient value of about 0.49 between
the normalized 11-yr running mean of WMI and ENSO index, however, the WMI-ENSO relationship is not consistently highly correlated.
The temporal evolution of correlation between WMI and ENSO indices in both 11-yr and 21-yr moving window shows that the WMI-ENSO
relationship clearly undergo low-frequency oscillation. Obviously, both observational and IPSL air-sea coupled modeling WMI
index has a near-decadal peak with PDO timescales and internal peaks with ENSO timescales by applying the Multitaper method.
Moreover, the cross wavelet and wavelet coherence analysis of WMI/ENSO indicate that there is a larger significant sections
with an in phase behavior between WMI and ENSO at period of 20–30 yrs, suggesting that the interdecadal variation of the WMI-ENSO
relationship might exist. 相似文献
12.
A simplified data set with 8°×8° grid system in a region of 32°S-32°N from 1951 to 1979 for the elements of sea surface temperature (SST),zonal wind at sea level (U),sea level pressure (SLP) and total cloud amount (CA) is made from the COADS.The oscillation components with periods of 2 years (QBO),3.5 years (SO) and 5.5 years (FYO) in interannual low-frequency oscillations have been studied by using the methods of extended EOF (EEOF) and lag comelation analysis with the oscillational components of SST in the equator of eastern Pacific as the reference element.In our paper,the relationship between oscillation components and occumence of El Nino is also investigated. 相似文献
13.
R. D'Arrigo E. Cook R. Villalba B. Buckley J. Salinger J. Palmer K. Allen 《Climate Dynamics》2000,16(8):603-610
The limited length and spatial coverage of instrumental climate data for many areas of the Southern Hemisphere impedes the
study of atmosphere-ocean dynamics prior to the past century. Such analyses are important for understanding interannual to
decadal variation of the Southern Hemisphere circulation and whether recent changes are related to anthropogenic effects rather
than natural variability. We use a middle- to high-latitude tree-ring width data set (from Tasmania, New Zealand and Tierra
del Fuego) to reconstruct sea-level pressure (SLP) variability spanning the Tasman Sea and vicinity since ad 1740. The variables reconstructed are austral summer (November–March) SLP for Hobart, Tasmania (43°S, 147°E) and the Chatham
Islands, New Zealand (44°S, 177°E), as well as a meridional circulation index (Hobart-Chatham Islands index) which measures
the pressure gradient between these two stations. The three reconstructions are well verified statistically and capture between
40 and 48% of the variance in the SLP data. The instrumental and estimated SLP show similar spatial patterns of correlation
with the sea surface temperature (SST) field for the Pacific. Statistically significant (above 95% level) 3–3.5 year spectral
peaks are identified in the three reconstructions using multitaper spectral analysis, and a significant 4–5 year peak is found
in both the Chatham Islands and Hobart-Chatham Islands SLP reconstructions. These two modes are within the bandwidth of the
El Nino-Southern Oscillation. Although very speculative, they may also correspond to a proposed Antarctic circumpolar wave
of SLP, SST, wind and sea-ice extent, believed to play a key role in atmosphere-ocean circulation for the Southern Hemisphere.
Received: 30 November 1998 / Accepted: 13 December 1999 相似文献
14.
Anatomy of the synoptic conditions occurring over southern Greece during the second half of the 20th century. Part I. Winter and summer 总被引：1，自引：0，他引：1
P. A. Kassomenos 《Theoretical and Applied Climatology》2003,75(1-2):65-77
Summary ?In this study a methodology for grouping seasonal circulation types occurring over an area is introduced. This procedure
combines the surface air mass characteristics affecting the area with the synoptic conditions prevailing over it. Factor Analysis
and Cluster Analysis are used to derive the circulation types, based on surface meteorological data and surface pressure grid
data. The methods are applied to Athens, Greece, using data over the period 1954–1999 for winter (December, January, February)
and summer (June, July, August) seasons. The daily circulation types are analyzed at surface level and their temporal evolution
is examined via transition matrices. 315 grid points are used covering the area between 25° N to 60° N and 10° W to 40° E.
This analysis derives 8 circulation types for the winter and 4 for the summer.
A reduction in cyclonic activity and an increase in anticyclonic activity in the Central Mediterranean are detected in the
late 1980s and early 1990s during the winter period. During summer the etesian winds and the local flows are dominant over
Athens.
Received February 20, 2002; accepted January 9, 2003
Published online May 26, 2003 相似文献
15.
东亚地区低频振荡的经向传播及中纬度的低频波动 总被引：11，自引：3，他引：11
本文利用1981年6—9月欧洲中期天气预报中心(ECMWF)网格点资料分析了东亚地区低频(准40天)振荡的传播特性与结构特征,发现在120°E经度上的高空(低空)副热带地区有一个低频纬向风(经向风)经向传播的分离带(汇合带),指出中纬度低频纬向风振荡是准地转的,且高低空振荡同位相。同时揭示出:亚洲地区中纬度(35°N)高空低频纬向风的向东传播是波长为60—90个经度、移速为1.5—2.0个经度/d的中纬度低频波动东移的结果。这种低频涡旋移至东亚沿海地区常会发展,这种发展可能与急流中心附近正压不稳定能量的供给有关。 相似文献
16.
利用2003~2011年TIDI(TIMED Doppler Interferometer)风场观测数据研究了中间层顶区域80~105 km纬向平均风场年振荡和半年振荡振幅和相位的全球分布结构,并给出了它们的年际变化。在热带地区,纬向风半年振荡最显著。振幅峰值中心位于南半球10°S~20°S范围,出现与平流层半年振荡类似的相对于赤道不对称的分布,并且振幅峰值与以前在该区域的研究结果存在较大差别。在中高纬度地区,纬向风和经向风被年振荡所控制。纬向风在高度100 km以下中高纬度都存在振幅大值中心;经向风年振荡只出现在两半球中纬度高度95 km以下,并且南北半球振幅峰值中心分布不一致。分析结果还显示年振荡和半年振荡振幅存在显著地年际变化,相位的年际变化则较小,但北半球热带地区经向风年振荡振幅和相位表现出2年周期的变化。 相似文献
17.
Summary Monthly rainfall totals at 7 stations across Turkey and sea level pressure (SLP) in 16 grid points in the region delimited
by the 20° E and 50° E longitudes and by the 30° N and 45° N latitudes were analysed. Data were available for a period longer
than sixty years. The standard deviations of SLP at each grid point for each month, were calculated and mapped. For each station,
months were defined as dry or wet according to their z scores: ≤ −1.0 or ≥ 1.0 respectively. Maps showing the SLP z scores of the corresponding dry or wet months for each station were prepared. The maps, enable to distinguish between SLP patterns associated with dry or wet conditions.
Furthermore, correlations between monthly rainfall in each of the stations and SLP at each grid point were performed. The
correlation coefficients were mapped.
(a) The variability of the SLP decreases from the Balkans towards the Arabian Peninsula and is much larger in winter as compared
with summer. (b) Relationship between rainfall in Turkey and the regional SLP is large in winter and non existing in summer.
(c) Pressure patterns associated with dry conditions, show usually positive SLP departures, whereas, pressure patterns associated with wet conditions show usually negative SLP departures. (d) There is a great resemblance between pressure patterns associated with
wet conditions and correlation maps of the same months.
Received September 4, 2000 Revised January 15, 2001 相似文献
18.
A new winter Aleutian Low (AL) intensity index was defined in this paper. A centurial-long time series of this index was constructed
using the sea level pressure (SLP) data of nearly 100 years. The features of interannual and decadal variability of the winter
AL intensity since 1900 were analyzed by applying the wavelet analysis. The relationship between the winter AL intensity and
atmospheric circulation was examined. The cross-wavelet analysis technique was used to further reveal the relationship between
the AL intensity and sea surface temperature (SST) in the equatorial eastern Pacific (EEP) and tropical Indian Ocean (TIO)
in winter. The results indicate that: 1) On the interannual timescale, the winter AL intensity displays 3–7-yr oscillations,
while on the decadal timescale, 8–10-yr and 16–22-yr oscillations are more obvious. 2) Of the linkage to atmospheric circulation,
both AO (Arctic Oscillation) and PNA (Pacific North America pattern) are closely associated with winter AL intensity on the
interannual timescale, but only PNA contributes to the variation of winter AL intensity on the decadal timescale. 3) As to
the ocean impact, winter EEP SST is a major factor affecting the winter AL intensity on the interannual timescale, especially
on the 3–7-yr periods. However, on the decadal timescale, though both the TIO and EEP SSTs are associated with the AL intensity
in winter, the TIO SST impact is more significant. 相似文献
19.
RESEARCH ON INTERANNUAL CHANGE ABOUT TELECONNECTION OF GENERAL CIRCULATION IN SUMMER DURING 1980s OVER THE NORTHERN HEMISPHERE 
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下载免费PDF全文 In the paper the 5°×10°latitude-longitude grid point data of daily 500 hPa geopotential height over the NorthernHemisphere(NH)in summer(June—August)during 1980s are used.The base point(20°N,120°E)is selected to calcu-late point correlation between the base point and other grid points.We find that the summer heat source anomaly of thetropical western Pacific causes anomaly of summer general circulation over NH and teleconnection of general circula-tion similar to PNA pattern forms from East Asia to North America.The teleconnections show great interannualchanges. 相似文献
20.
选取热带测雨卫星(Tropical Rainfall Measuring Mission,TRMM)微波成像仪(TRMM Microwave Imager,TMI)液态水路径(liquid water path,LWP)轨道像元数据为研究对象,探讨了将瞬时探测以及逐月的像元数据进行格点化(0.1°、0.25°、0.5°、1.0°和2.5°五种格点分辨率)时,格点数据的失真情况。对TMI瞬时探测的个例分析结果表明,细分辨率(0.1°、0.25°和0.5°)格点能保留原始像元数据的细节;而随着网格变粗,细节受到较大的平滑。因此对于中尺度到天气尺度的天气系统分析而言,将卫星轨道数据处理到网格尺度不大于0.5°的格点更合适。对逐月LWP像元资料格点化处理的分析表明,细分辨率格点能保留LWP空间分布细节,尽管5种分辨率下LWP的概率密度分布(probability density function,PDF)均相近。因此,对月尺度及以上的气候分析研究而言,格点尺度大小对卫星像元数据格点化的影响不显著。最后利用本实验室计算的TMI/LWP格点数据与欧洲中期数值预报中心再分析资料(European Centre for Medium-range Weather Forecasts Interim reanalysis,ERA-Interim)和NCEP再分析资料(NCEP Climate Forecast System Reanalysis,NCEP CFSR)进行了对比,发现两种再分析资料都高估了LWP;TMI/LWP格点数据与两种再分析资料LWP的多年变化趋势大致相同。 相似文献