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1.
2010年西北太平洋与南海热带气旋活动异常的成因分析 总被引：1，自引：0，他引：1
利用中国气象局热带气旋（TC）资料、NCEP/NCAR 再分析资料和美国 NOAA 向外长波辐射（OLR）等资料,分析了2010年西北太平洋（WNP）及南海（SCS）热带气旋活动异常的可能成因,讨论了同期大气环流配置和海温外强迫对TC生成和登陆的动力和热力条件的影响。结果表明,2010年生成TC频数明显偏少,生成源地显著偏西,而登陆TC频数与常年持平。导致7～10月TC频数明显偏少的大尺度环境场特征为：副热带高压较常年异常偏强、西伸脊点偏西,季风槽位置异常偏西,弱垂直风切变带位置也较常年偏西且范围偏小,南亚高压异常偏强,贝加尔湖附近对流层低高层均为反气旋距平环流,这些关键环流因子的特征和配置都不利于 TC 在WNP的东部生成。影响TC活动的外强迫场特征为：2010年热带太平洋经历了El Ni?o事件于春末夏初消亡、La Ni?a事件于7月形成的转换;7～10月,WNP海表温度维持正距平,140°E以东为负距平且对流活动受到抑制;暖池次表层海温异常偏暖,对应上空850 hPa为东风距平,有利于季风槽偏西和TC在WNP的西北侧海域生成。WNP海表温度和暖池次表层海温的特征是2010年TC生成频数偏少、生成源地异常偏西的重要外强迫信号。有利于7～10月热带气旋西行和登陆的500 hPa风场特征为：北太平洋为反气旋环流距平,其南侧为东风异常,该东风异常南缘可到25°N,并向西扩展至中国大陆地区;南海和西北太平洋地区15°N以南的低纬也为东风异常;在这样的风场分布型下,TC容易受偏东气流引导西行并登陆我国沿海地区。这是2010年生成TC偏少但登陆TC并不少的重要环流条件。 相似文献
2.
THE RELATIONSHIP BETWEEN GLOBAL WARMING AND THE VARIATION IN TROPICAL CYCLONE FREQUENCY OVER THE WESTERN NORTH PACIFIC 总被引：3，自引：1，他引：2
The relationship between global warming and the variation in tropical cyclone (TC) genesis
frequency is analyzed using the data of the Tropical Cyclone Year Book by the China Meteorological
Administration and the National Centers for Environmental Prediction (NCEP) reanalysis data from 1949
to 2007. The observational results indicate that the average sea surface temperature (SST) in the
Intertropical Convergence Zone (ITCZ) region (10°N – 20°N, 100°E – 140°E) increases by 0.6°C against
the background of global warming, while the frequency of tropical cyclone geneses in this region decreases
significantly. Generally, the rise of SSTs is favorable for the genesis of tropical cyclones, but it is now
shown to be contrary to the normal effect. Most of the tropical cyclones in the western North Pacific (WNP)
are generated in the ITCZ. This is quite different from the case in the Atlantic basin in which the tropical
cyclones are mostly generated from the easterly wave. Our research results demonstrate that the ITCZ has a
weakening trend in strength, and it has moved much more equatorward in the past 40 years; both are
disadvantageous to the formation of tropical cyclones. Furthermore, our study also found that the ridge of
the subtropical high tends to shift slightly equatorward, which is another adverse mechanism for the
formation of tropical cyclones. 相似文献
3.
4.
利用常规气象观测资料、NCEP/NCAR 1°×1°的月平均再分析资料、NOAA卫星观测的OLR资料和中国气象局台风年鉴资料,对2014年8月西北太平洋和南海无TC生成的原因进行了诊断分析,结果表明：极地冷空气南侵,造成8月上中旬副热带高压偏东偏南,下旬冷空气减弱,副热带高压偏西偏南,致使副热带高压南侧偏东信风与赤道西风的汇合区位置异常偏南;马斯克林高压偏弱,导致索马里急流和东印度洋越赤道气流也弱,印度半岛中低层季风低压或季风槽极其不活跃。澳大利亚高压路径偏东或偏西和势力偏弱,则南海南部越赤道气流亦弱。8月上中旬台风主要源地的海表温度明显偏低,不能酿成低层高温高湿的大气;月内西北太平洋和南海大气的对流活动很弱,层结较稳定、风速垂直切变大,均不利于TC发生发展。在南海到菲律宾以东洋面低层为弱的正涡度区和负散度区,有辐合上升运动,但垂直速度很小,不能满足TC尺度的环流发生和发展;南亚高压和副高南侧东风扰动造成对流层高层为弱上升区,不能形成高空辐散机制,不利于上升气流维持和加强。故此,8月在异常偏南的ITCZ中生成的4个热带扰动最终均未能发展成台风。 相似文献
5.
利用1949—2021年中国气象局上海台风研究所热带气旋资料、NCEP/NCAR再分析资料、NOAA重构的海表温度资料（SST）和大气向外长波辐射（OLR）资料,采用线性趋势分析、Mann-Kendall检验等方法分析了近73年7—9月登陆华南热带气旋频数的变化特征。采用合成分析的方法研究7—9月登陆华南热带气旋频数异常与同期大气环流和海温的关系。结果表明,1949—2021年7—9月,登陆华南热带气旋有243个,年均3.3个,占全年登陆总数的70.2%。登陆华南热带气旋频数具有显著的年际和年代际变化特征。1973年最多（7个）,1950年最少（0个）;在1990年代中期由前期偏多转为后期偏少,但没有突变发生。近73年7—9月登陆华南热带气旋频数以0.1（10a）-1的速率减少。7—9月登陆华南热带气旋频数异常与大气环流和海温异常密切相关,在异常多、少年同期：（1）大气环流差值场上,南亚高压偏强、偏东、偏北,副高偏西、偏北、偏强,110°E以东的赤道东风引导气流偏强,季风槽加强,北半球中低纬海平面气压场东高西低,北高南低,同时南海、热带西太平洋对流活动加强。（2）海温差值场上,赤道中东太平洋偏冷,西太平洋暖池偏暖,沃克环流加强。高中低层大气环流和海温这种差异可能是导致登陆华南热带气旋频数异常的原因。 相似文献
6.
In the context of a model of tropical cyclone intensity based on an improved meso-scale atmospheric model, numerical simulation is performed of the track and intensity variation of tropical cyclones(TC) arising from sea surface temperature(SST) variation over a specified sea region. Evidence suggests that the model is capable of modeling quite welt the track and intensity of TC:SST variation leads to an abrupt change in the cyclone intensity:the response of the cyclone to the abrupt SST change lasts 8-12 h. 相似文献
7.
This study evaluates the performance of a regional climate model in simulating two types of synoptic tropical weather disturbances: convectively-coupled Kelvin and easterly waves. Interest in these two wave modes stems from their potential predictability out to several weeks in advance, as well as a strong observed linkage between easterly waves and tropical cyclogenesis. The model is a recent version of the weather research and forecast (WRF) system with 36-km horizontal grid spacing and convection parameterized using a scheme that accounts for key convective triggering and inhibition processes. The domain spans the entire tropical belt between 45°S and 45°N with periodic boundary conditions in the east–west direction, and conditions at the meridional/lower boundaries specified based on observations. The simulation covers 6 years from 2000 to 2005, which is long enough to establish a statistical depiction of the waves through space-time spectral filtering of rainfall data, together with simple lagged-linear regression. Results show that both the horizontal phase speeds and three-dimensional structures of the waves are qualitatively well captured by the model in comparison to observations. However, significant biases in wave activity are seen, with generally overactive easterly waves and underactive Kelvin waves. Evidence is presented to suggest that these biases in wave activity (which are also correlated with biases in time–mean rainfall, as well as biases in the model’s tropical cyclone climatology) stem in part from convection in the model coupling too strongly to rotational circulation anomalies. Nevertheless, the model is seen to do a reasonable job at capturing the genesis of tropical cyclones from easterly waves, with evidence for both wave accumulation and critical layer processes being importantly involved. 相似文献
8.
采用1948—2014年NCEP/NCAR大气再分析资料以及延伸重建海温资料,基于大气海洋间不同的主导关系对冬季北太平洋大范围海温异常进行分类,探究其相应的海气结构特征。结果表明:1)大气影响海洋的个例多于海洋影响大气的个例,即在冬季北太平洋大气强迫海洋占主要地位,但也存在海洋对大气的反馈作用。2)对于大气影响海洋而言,SST(Sea Surface Temperature)暖异常区上空主要伴随着东北—西南走向的相当正压高低压异常(东北高西南低),对应东南风异常以及显著的深厚暖异常,表现出相当正压暖/脊结构,冷异常情况与此相反。SST异常为净热通量异常与风速异常共同作用引起。3)对于海洋影响大气而言,在SST暖异常区上空西部为南北向高低压异常(北高南低),东部为低压异常,对应偏东风异常。在SST冷异常区上空为偶极型的南北向高低压异常(南高北低),对应偏西风异常;位势高度异常表现出相当正压结构且较大气影响海洋时相对偏弱,大气暖(冷)温度异常比较浅薄且主要局限于对流层低层。4)海洋温度结构异常主要表现为,在大气影响海洋时海温异常由表层下传,海洋影响大气时为上下一致的温度异常。 相似文献
9.
Climate responses in the tropical pacific associated with atlantic warming in recent decades 总被引：2，自引：0，他引：2
Soojin Hong In-Sik Kang Ildae Choi Yoo-Geun Ham 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(2):209-217
In this study, we investigated the impact of the Atlantic decadal-scale sea surface temperature (SST) variation on the tropical Pacific climate using a Atmospheric General Circulation Model (AGCM). During the recent decade from 2000 to 2010 when the Atlantic SST has sharply increased, observations have shown that the strong easterly and increased precipitation anomalies appeared over the western-central Pacific. It is different from the conventional Gilltype response in which the easterly due to heating in the Atlantic is expected to be extended to the Indian Ocean. We have found that the warm pool over the western Pacific plays an important role in enhancing the atmospheric response to the Atlantic SST forcing in the Pacific basin. Simplified Aqua planet GCM experiments showed that the central location of the anomalous easterly over the Pacific produced by the Atlantic SST forcing highly depends on the location of the idealized warm pool. The reason for this is because the moisture feedback is strongest over the warm pool region, which leads to additional local anomalous convergence, and therefore the easterly produced by the Atlantic SST forcing is enhanced only over the east of the warm pool region. 相似文献
10.
利用1978-2013年美国NOAA逐候MJO指数和中国气象局上海台风研究所热带气旋资料,研究了MJO与影响广西热带气旋发生发展的联系。结果表明,当MJO处于非洲大陆和西印度洋时,热带气旋生成区域上空为异常东风带;而当MJO处于西太平洋时,热带气旋生成区域北侧为东风异常带、南侧为西风异常带,有利于季风槽或气旋性环流加强,导致影响广西热带气旋频数偏多。当MJO处于东印度洋时,南海上空风场存在明显的向南分量,热带气旋生成数少、位置偏南;而当MJO处于东太平洋时,热带西太平洋对流受到抑制,导致影响广西热带气旋偏少。 相似文献
11.
Previous studies suggest that spring SST anomalies over the northern tropical Atlantic(NTA) affect the tropical cyclone(TC) activity over the western North Pacific(WNP) in the following summer and fall. The present study reveals that the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is not stationary. The influence of spring NTA SST on following summer–fall WNP TC genesis frequency is weak and insignificant before, but strong and significant after, the late 1980 s. Before the late 1980 s, the NTA SST anomaly-induced SST anomalies in the tropical central Pacific are weak, and the response of atmospheric circulation over the WNP is not strong. As a result, the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is insignificant in the former period. In contrast,after the late 1980 s, NTA SST anomalies induce pronounced tropical central Pacific SST anomalies through an Atlantic–Pacific teleconnection. Tropical central Pacific SST anomalies further induce favorable conditions for WNP TC genesis,including vertical motion, mid-level relative humidity, and vertical zonal wind shear. Hence, the connection between NTA SST and WNP TC genesis frequency is significant in the recent period. Further analysis shows that the interdecadal change in the connection between spring NTA SST and following summer–fall WNP TC genesis frequency may be related to the climatological SST change over the NTA region. 相似文献
12.
Spring Arctic Oscillation-East Asian summer monsoon connection through circulation changes over the western North Pacific 总被引：5，自引：0，他引：5
Dao-Yi Gong Jing Yang Seong-Joong Kim Yongqi Gao Dong Guo Tianjun Zhou Miao Hu 《Climate Dynamics》2011,37(11-12):2199-2216
In the present study the links between spring Arctic Oscillation (AO) and East Asian summer monsoon (EASM) was investigated with focus on the importance of the North Pacific atmospheric circulation and sea surface temperature (SST). To reduce the statistical uncertainty, we analyzed high-pass filtered data with the inter-annual time scales, and excluded the El Ni?o/Southern Oscillation signals in the climate fields using a linear fitting method. The significant relationship between spring AO and EASM are supported by the changes of multi-monsoon components, including monsoon indices, precipitation, and three-dimensional atmospheric circulations. Following a stronger positive spring AO, an anomalous cyclonic circulation at 850?hPa appears in southeastern Asia and the western North Pacific in summer, with the easterly anomalies spanning from the Pacific to Asian continent along 25°N?C30°N and the westerly anomalies south of 15°N. At the same time, the summer western North Pacific subtropical high becomes weaker. Consistently, the positive precipitation anomalies are developed over a broad region south of 30°N stretching from southern China to the western Pacific and the negative precipitation anomalies appear in the lower valley of the Yangtze River and southern Japan. The anomalous cyclone in the western North Pacific persisting from spring to summer plays a key role in modulating EASM and monsoon precipitation by a positive air-sea feedback mechanism. During spring the AO-associated atmospheric circulation change produces warmer SSTs between 150°E?C180° near the equator. The anomalous sensible and latent heating, in turn, intensifies the cyclone through a Gill-type response of the atmosphere. Through this positive feedback, the tropical atmosphere and SST patterns sustain their strength from spring to summer, that consequently modifies the monsoon trough and the western North Pacific subtropical high and eventually the EASM precipitation. Moreover, the SST response to AO-circulation is supported by the numerical simulations of an ocean model, and the anomalous atmospheric circulation over the western North Pacific is also reproduced by the dedicated numerical simulations using the coupled atmosphere?Cocean model. The observation evidence and numerical simulations suggest the spring AO can impact the EASM via triggering tropical air-sea feedback over the western North Pacific. 相似文献
13.
IMPACT OF TROPICAL INTRASEASONAL OSCILLATION ON THE TRACKS OF TROPICAL CYCLONES IN THE WESTERN NORTH PACIFIC 总被引：1，自引：1，他引：0
In this work,an index of tropical 20-90 d oscillation(intra-seasonal oscillation;ISO)in the western North Pacific(WNP)was determined via the combined empirical orthogonal function(EOF)method using daily outgoing longwave radiation(OLR)field data from the National Oceanic and Atmospheric Administration(NOAA),daily wind field data(at 850 hPa)from the European Centre for Medium-Range Weather Forecasts(ECMWF)and referencing the Madden-Julian oscillation(MJO)index proposed by Wheeler and Hendon.An in-depth investigation was conducted to examine the impact of the ISO on changes in tropical cyclone(TC)tracks in the WNP during different ISO phases.The research results indicate that during the easterly phase of the ISO,under the impact of the northeastern airflow of anti-cyclonic ISO circulation,the easterly airflow south of the western Pacific subtropical high is relatively weak,and TCs generated in the subtropical high tend to change their tracks east of 140°E;during the westerly phase,there is a relatively high probability that TCs change their tracks west of 140°E.This work also analyzed the ISO flow field situation in cases of typhoons and determined that the track of a tropical cyclone will experience a sudden right turn when the center of the ISO cyclonic(anti-cyclonic)circulation coincides with that of the cyclone. 相似文献
14.
The sea surface temperature (SST) or sea level pressure (SLP) has usually been used to measure the strength of El Niño–Southern Oscillation (ENSO) events. In this study, two new indices, based on the upper-ocean heat content (HC), are proposed to quantify the two “flavours” of El Niño (i.e., the Cold Tongue El Niño (CTE) and Warm Pool El Niño (WPE)). Compared with traditional SST or SLP indices, the new HC-based indices can distinguish CTE and WPE events much better and also represent the two leading modes of the interannual variability of the atmosphere–ocean coupled system in the tropical Indo-Pacific region. The two leading modes are obtained by performing multivariate Empirical Orthogonal Function analysis on two oceanic variables (SST and HC) over the tropical Pacific (30°S–30°N, 120°E–80°W) and six atmospheric variables (outgoing longwave radiation, SLP, streamfunction, and velocity potential at 850?hPa and 200?hPa) over the tropical Indo-Pacific region (30°S–30°N, 60°E–80°W) for the period 1980–2010. Because the two new HC-based indices are capable of better depicting coherent variations between the ocean and atmosphere, they can provide a supplementary tool for ENSO monitoring of and climate research into the two flavours of El Niño. 相似文献
15.
Using a suite of lateral boundary conditions, we investigate the impact of domain size and boundary conditions on the Atlantic tropical cyclone and african easterly Wave activity simulated by a regional climate model. Irrespective of boundary conditions, simulations closest to observed climatology are obtained using a domain covering both the entire tropical Atlantic and northern African region. There is a clear degradation when the high-resolution model domain is diminished to cover only part of the African continent or only the tropical Atlantic. This is found to be the result of biases in the boundary data, which for the smaller domains, have a large impact on TC activity. In this series of simulations, the large-scale Atlantic atmospheric environment appears to be the primary control on simulated TC activity. Weaker wave activity is usually accompanied by a shift in cyclogenesis location, from the MDR to the subtropics. All ERA40-driven integrations manage to capture the observed interannual variability and to reproduce most of the upward trend in tropical cyclone activity observed during that period. When driven by low-resolution global climate model (GCM) integrations, the regional climate model captures interannual variability (albeit with lower correlation coefficients) only if tropical cyclones form in sufficient numbers in the main development region. However, all GCM-driven integrations fail to capture the upward trend in Atlantic tropical cyclone activity. In most integrations, variations in Atlantic tropical cyclone activity appear uncorrelated with variations in African easterly wave activity. 相似文献
16.
利用印度气象局（India Meteorological Department,IMD）、国际气候管理最佳路径档案库（International Best Track Archive for Climate Stewardship,IBTrACS）提供的1982—2020年阿拉伯海热带气旋路径资料,美国国家环境预报中心（National Centers for Environmental Prediction,NCEP）再分析资料,对近39 a阿拉伯海热带气旋源地和路径特征、活跃区域、频数及气旋累积能量（accumulated cyclone energy,ACE）指数的季节特征和年际变化特征进行分析,并结合环境因素,说明其物理成因。结果表明：阿拉伯海热带气旋多发于10°~25°N,65°~75°E海域,5—6月、9—12月发生频数较高且强度较强,1—4月、7—8月发生频数较低且气旋近中心最大风速均小于35 kn;频数的季节变化主要受控于垂直风切变要素;阿拉伯海热带气旋发生频数和ACE近年有上升趋势,年际变化主要受控于海面温度（sea surface temperature,SST）和850 hPa相对湿度要素。 相似文献
17.
基于1979～2019年日本气象厅提供的地表感热与大气环流再分析资料,美国国家海洋和大气管理局提供的月均海表温度数据和国家气象信息中心提供的月降水数据,分析了夏季伊朗高原感热和热带印度洋海温与同期塔里木盆地降水的可能联系。奇异值分解分析表明,两个地区热力异常均与塔里木盆地夏季降水联系紧密,可以通过影响500 hPa风场和水汽输送来调制塔里木盆地夏季降水的变化。当伊朗高原感热和热带印度洋海温均偏强（弱）时,对应中亚上空受异常气旋（反气旋）控制,蒙古高原上空为反气旋（气旋）控制,二者共同作用塔里木盆地上空盛行异常偏南（北）风,形成有利（不利）的动力条件;同时印度半岛上空受异常反气旋（气旋）环流控制,中亚上空为异常气旋（反气旋）,阿拉伯海水汽可（不可）由以上两个系统两步输送至新疆上空,导致盆地夏季降水整体偏多（少）。当伊朗高原和热带印度洋热力异常反相变化时,盆地降水空间差异性较大,部分区域降水偏多,部分地区降水偏少。 相似文献
18.
A significant negative correlation between the total rainfall averaged over South Korea and the Niño-3.4 index was found for the month of September. To find out the reason for this negative correlation, composite analyses were carried out for the highest and lowest 8 years of the Niño-3.4 index. During the strong El Niño year, an anomalous anticyclone occurs in the continental East Asia, while an anomalous cyclone emerges in the subtropical western Pacific. The resultant eastward pressure gradient force induces anomalous northerlies in most regions of East Asia, which produces anomalous cold and dry conditions throughout the troposphere between 120° and 140°E, reducing the Korean rainfall. It is also found that during El Niño year, tropical cyclones (TCs) tend to recurve far east offshore of Japan because the weakening of the western North Pacific subtropical high (WNPSH). During La Niña years, on the other hand, the strengthening and westward extension of the WNPSH render more TCs influencing the Korean peninsula. Therefore, the TC track changes associated with El Niño-Southern Oscillation is another contributor to change of the Korean rainfall. 相似文献
19.
青藏高原动力和热力作用对热带大气环流影响的数值研究 总被引：7，自引：28，他引：7
应用在CCM3气候模式基础上发展的一个CCM3(R15L9)长期预报模式 ,进一步研究了青藏高原热力和动力作用对夏季热带地区大气环流的影响。结果表明 :在 6月初夏季节 ,青藏高原动力和热力作用在 30°N和 30°S一带有明显的增温效果 ,有利于北半球副热带西风减弱北移、热带高层东风增强北进、南半球西风带北压和赤道中低层西风形成和加强。加速了季节转换过程 ,有利于增强越赤道气流和南北半球的大气交换作用 ,还有利于在南海、菲律宾以东海面上热带气旋的形成和发展 ,以及140°E以东热带太平洋地区的东风波动的形成和发展 相似文献
20.
ERA40再分析资料揭示的北半球和东亚地区温带气旋生成频率变化 总被引：6，自引：0，他引：6
本文利用欧洲中心再分析数据ERA40的6小时间隔海平面气压场和一种改进的客观判定和追踪方法研究19582001年北半球和东亚地区温带气旋生成频率的气候态、年代际变化及可能原因。结果表明:(1)北半球温带气旋的源地主要位于北美东部(落基山下游地区)、西北大西洋地区、格陵兰至欧洲北部地区、蒙古地区和日本至西北太平洋地区。大洋的西岸和陡峭地形的背风坡有利于大气斜压性的增强和正涡度的发展,从而有利于地面气旋的形成。(2)年、冬季和春季30°～60°N气旋生成数目呈现减少的变化趋势,60°～90°N地区的气旋生成数呈增加的变化趋势。这在一定程度上支持了北半球风暴路径北移的观点。60°N以南和以北的温带气旋数目同北极涛动指数(AO)分别呈现负相关和正相关,这种相关性在年、春季和秋季最为显著。(3)1 958—2001年东亚地区的年气旋数目呈现明显的年代际变化。20世纪60年代至80年代中期40°～60°N、80°～140°E地区气旋数目呈增加趋势,而80年代中期之后温带气旋数目则锐减,主要原因是80年代以后该地区大气斜压性减弱,更高纬度地区的大气斜压性增强,从而导致了气旋源地的北移。在较低纬带的20°～40°N、110°～160°E地区气旋数目线性增加,这主要是由于位于40°～55°N的北太平洋风暴轴有向低纬度偏移的变化趋势造成的。 相似文献