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1.
Based on the simulations of 31 global models in CMIP5, the performance of the models in simulating the Hadley and Walker circulations is evaluated. In addition, their change in intensity by the end of the 21 st century(2080–2099) under the RCP4.5 and RCP8.5 scenarios, relative to 1986–2005, is analyzed from the perspective of 200 h Pa velocity potential.Validation shows good performance of the individual CMIP5 models and the multi-model ensemble mean(MME) in reproducing the meridional(zonal) structure and magnitude of Hadley(Walker) circulation. The MME can also capture the observed strengthening tendency of the winter Hadley circulation and weakening tendency of the Walker circulation. Such secular trends can be simulated by 39% and 74% of the models, respectively. The MME projection indicates that the winter Hadley circulation and the Walker circulation will weaken under both scenarios by the end of the 21 st century. The weakening amplitude is larger under RCP8.5 than RCP4.5, due to stronger external forcing. The majority of the CMIP5 models show the same projection as the MME. However, for the summer Hadley circulation, the MME shows little change under RCP4.5 and large intermodel spread is apparent. Around half of the models project an increase, and the other half project a decrease. Under the RCP8.5 scenario, the MME and 65% of the models project a weakening of the summer southern Hadley circulation. 相似文献
2.
Changes in the Tropical Cyclone Genesis Potential Index over the Western North Pacific in the SRES A2 Scenario 总被引：1，自引：0，他引：1
The Tropical Cyclone Genesis Potential Index (GPI) was employed to investigate possible impacts of global warming on tropical cyclone genesis over the western North Pacific (WNP). The outputs of 20th century climate simulation by eighteen GCMs were used to evaluate the models’ ability to reproduce tropical cyclone genesis via the GPI. The GCMs were found in general to reasonably reproduce the observed spatial distribution of genesis. Some of the models also showed ability in capturing observed temporal vari... 相似文献
3.
现阶段使用的热带气旋潜在生成指数(Genesis Potential Index,GPI)在气候场的空间分布上能很好地拟合热带气旋的生成情况,但在热带气旋的年际变化拟合上效果很差。本研究考虑了相对涡度在热带气旋年际变化拟合上的重要作用,并以此为出发点,尝试改善GPI在西北太平洋地区的拟合效果。基于对1979—2011年美国联合飓风警报中心提供的热带气旋最佳路径数据和NCEP/NCAR再分析资料数据集的研究,将之前GPI中的绝对涡度项替换为修正过的相对涡度项。科氏力项仍然保留;将南海(100°～120°E,5°～25°N)与西北太平洋地区(120°～180°E,5°～40°N)热带气旋生成的差异性也纳入了考量,并在这两个区域分别构建GPI公式,改善了对热带气旋生成的气候分布模拟。除此之外,较之已存的GPI指数,改进后的GPI还很大程度提高了GPI对热带气旋生成年际变化的拟合效果,特别是对弱热带气旋年际变化的拟合效果有了显著提升。 相似文献
4.
The possible changes of tropical cyclone(TC) tracks and their influence on the future basin-wide intensity of TCs over the western North Pacific(WNP) are examined based on the projected large-scale environments derived from a selection of CMIP5(Coupled Model Intercomparison Project Phase 5) models. Specific attention is paid to the performance of the CMIP5 climate models in simulating the large-scale environment for TC development over the WNP. A downscaling system including individual models for simulating the TC track and intensity is used to select the CMIP5 models and to simulate the TC activity in the future.The assessment of the future track and intensity changes of TCs is based on the projected large-scale environment in the21 st century from a selection of nine CMIP5 climate models under the Representative Concentration Pathway 4.5(RCP4.5)scenario. Due to changes in mean steering flows, the influence of TCs over the South China Sea area is projected to decrease,with an increasing number of TCs taking a northwestward track. Changes in prevailing tracks and their contribution to basin-wide intensity change show considerable inter-model variability. The influences of changes in prevailing track make a marked contribution to TC intensity change in some models, tending to counteract the effect of SST warming. This study suggests that attention should be paid to the simulated large-scale environment when assessing the future changes in regional TC activity based on climate models. In addition, the change in prevailing tracks should be considered when assessing future TC intensity change. 相似文献
5.
基于美国冰雪资料中心(NSIDC)提供的卫星遥感雪水当量资料,评估了26个CMIP5(Coupled Model Inter-comparison Project)耦合模式对1981~2005年欧亚大陆冬季雪水当量的模拟能力,在此基础上应用多模式集合平均结果,预估了21世纪欧亚大陆雪水当量的变化情况。结果表明,CMIP5耦合模式对欧亚大陆冬季雪水当量空间分布具有一定的模拟能力,能够再现出欧亚大陆冬季雪水当量由南向北递增、青藏高原积雪多于同纬度其他地区的特征;就雪水当量的幅值而言,几乎所有模式均显著低估了西伯利亚中部雪水当量的大值中心,对中国东北地区雪水当量的模拟也显著偏低,但模式对乌拉尔山以西的东欧平原、我国北方及蒙古地区冬季雪水当量的模拟却比卫星遥感资料显著偏大,此外模式对堪察加半岛及以北的西伯利亚东北部地区的雪水当量也明显偏大。对于青藏高原地区,虽然部分模式可以模拟出青藏高原东部的雪水当量大值区,但大多数模式对青藏高原西部雪水当量的模拟却明显偏大,存在虚假的大值中心。对遥感反演资料的EOF(Empirical Orthogonal Function)分解表明,对于EOF第一个模态所对应欧亚大陆全区一致的年代际变化特征,仅有少数模式具有一定的模拟能力,大多数模式以及多模式集合的结果均未能予以反映;对应于欧亚大陆雪水当量年际变化的EOF第二模态而言,仅有少数模式(如俄罗斯的INMCM4)具有一定的再现能力,绝大多数模式对该模态及其时间演变的特征没有模拟能力。比较CMIP5多模式的集合预估结果与1981~2005年基准时段的雪水当量,可以发现在RCP4.5排放情景下,西伯利亚中东部地区的雪水当量相对于基准时段显著增加,区域平均的增加量在21世纪前、中、后期分别为4.1mm、5.4 mm和6.8 mm,且随时间增加得更显著;对90°E以西的欧洲大陆和青藏高原地区,其雪水当量则相对减少,减少的幅度和显著性也随时间而增大。就雪水当量的相对变化而言,在欧亚大陆东北部存在雪水当量相对变化的大值区,在21世纪后期相对变化显著区大都在5%~10%;但在青藏高原、斯堪的纳维亚半岛进和东欧平原,并没有发现雪水当量相对变化的髙值区,这是由于这些区域冬季雪水当量的幅值较大的缘故。RCP8.5情景下欧亚大陆雪水当量的变化特征与RCP4.5相类似,只是变化的幅度更大。 相似文献
6.
8个CMIP5模式对中国极端气温的模拟和预估 总被引：14，自引：0，他引：14
利用8个耦合模式比较计划第五阶段（CMIP5）模式结果,采用加权平均方法进行多模式集合,并与NCEP再分析资料进行对比分析,评估了CMIP5模式对中国极端气温的模拟效果,在此基础上,对未来极端气温进行预估。CMIP5模式对中国8个极端气温指数和20年一遇最高（低）气温有模拟能力,所有极端气温指数模拟和观测结果的时间相关均达到0.10显著性水平,20年一遇最高、最低气温模拟和观测结果空间相关系数均超过0.98。在中等排放RCP4.5情景下,未来中国极暖（冷）日数增多（减少）,到21世纪中期热浪指数增加2.6倍,到21世纪末期寒潮指数减少71%,20年一遇最高（低）气温在中国地区均呈现升高趋势,局部升温幅度达到4℃。 相似文献
7.
Tropical Cyclone Genesis Potential Index over the Western North
Pacific Simulated by LASG/IAP AGCM 
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下载免费PDF全文 Tropical cyclone genesis potential index(GPI) is a useful metric for gauging the performance of global climate models in the simulation of tropical cyclone(TC) genesis.The performance of LASG/IAP AGCM GAMIL2.0 in the simulation of GPI over the western North Pacific(WNP) is assessed in this paper.Since GPI depends on large scale environmental factors including low-level vorticity at 850 hPa,relative humidity at 700 hPa,vertical wind shear between 850 and 200 hPa,maximum potential intensity(MPI),and vertical velocity,the bias of GPI simulation is discussed from the perspective of thermal and dynamical factors.The results are compared with the ECMWF reanalysis data(ERA40).The analyses show that both the climatological spatial pattern and seasonal cycle of GPI over the WNP are reasonably simulated by GAMIL2.0,but due to the overestimation of relative humidity,the simulated GPI extends to 170°E,about 10°east to that in the reanalysis data.It is demonstrated that the bias in the simulation of monsoon trough,which is about 5°north to the reanalysis,leads to an overestimation of GPI during May-June and September-October,but an underestimation during July-August.Over the WNP,the response of GPI to ENSO is well captured by GAMIL2.0,including the eastward(westward) shift of TC genesis location during El Nin o(La Nin a) years.However,the anomalous convective center associated with El Nin o shifts westward about 20°in comparison to ERA40,which leads to the biases in both vertical velocity and relative humidity.These eventually result in the westward deflection of the boundary between the positive and negative GPI centers along 20°-30°N.The results from this study provide useful clues for the future improvement of GAMIL2.0. 相似文献
8.
本文择优选取了国际耦合模式比较计划第五阶段（CMIP5）中19个气候模式的试验数据，预估了RCP4.5和RCP8.5典型浓度路径情景下21世纪末（2080～2099年）西北太平洋地区（0°～40°N，100°E～180°）台风环境场和台风生成潜力指数（IGP）变化。结果表明，相对于1986～2005年参考时段，21世纪末西北太平洋海洋表面温度（SST）增加，垂直风切变（VWS）和向外长波辐射（OLR）均在其与台风频数呈显著负相关的区域减少，有利于台风生成和发展；由大陆向南海延伸的低压系统减弱，不利于台风活动。总体上，在RCP8.5情景下台风环境场的变化较RCP4.5情景相对更大。利用信噪比进一步考察了模式间差异性，SST变化的信噪比在大部分地区大于3.0，在低压系统控制区海平面气压变化的信噪比大于1.0，模式间一致性较好；对于VWS和OLR，信噪比小于0.6，模式间差异较大；但在与台风频数显著负相关的地区，对OLR变化方向的模拟在模式间高度一致。与以上环境场变化相对应，未来西北太平洋IGP显著增加。 相似文献
9.
GFDL_RegCM对21世纪西北太平洋热带气旋活动的情景预估 总被引：1，自引：0，他引：1
首先评估了GFDL模式对西北太平洋热带气旋(TC)环境热力及动力因子的模拟性能,再利用夏威夷大学国际太平洋研究中心高分辨率区域气候模式( IPRC-RegCM),进行降尺度研究西北太平洋TC活动特征,在此基础上预估21世纪全球变暖背景下(A1B)西北太平洋TC活动的主要特点.结果显示,在西北太平洋TC活动区,GFDL控制试验的海平面温度(SST)比ERSST偏低.与NCEP/NCAR再分析资料相比,GFDL模拟的1980-1999年大尺度环流平均场表现为:副高脊线平均位置近乎一致,西伸脊点偏东,强度偏弱,面积偏小；季风槽槽线的范围偏小,强度偏弱；水平风垂直切变值在南海及菲律宾群岛海域偏小,而在160°E～170°W的20°N以南偏强.与NCEP/NCAR强迫的模拟结果相比,GFDL强迫得到的TC源地频数在南海偏少,菲律宾群岛以东海域偏多,两者的季节及年际变化特征相似.路径频数在南海北部和我国华南沿岸显著偏多.AlB情景下,西北太平洋TC生成数目将增加一倍,生成源地偏北且同时向东部洋而扩展,路径频数增多主要发生在20°N以北的中东部洋面上,移经西北太平洋西部的TC频数减少,由此影响我国的TC将减少.TC频数的季节分布发生较大变化,最多的月份在10月.TC平均强度增强,最大强度在10月增加最多,这与10月SST的增加和环境风切变的减小均为最大值有密切的关系. 相似文献
10.
西北太平洋热带气旋频数的气候变化及其与环境要素间的联系 总被引：7，自引：4，他引：3
使用Emanuel和Nolan完善的潜在生成指数(GPI)的计算方法,利用美国联合台风警报中心提供的热带气旋(TC)资料和欧洲中期数值天气预报中心提供的全球ERA-40再分析资料,比较了1970-2001年西北太平洋海域的TC生成频数和GPI的气候特征,分析了包含于GPI中的环境要素对西北太平洋TC频数年代际变化空间分布的影响.结果表明:GPI能近似地表述西北太平洋TC频数的季节变化和空间分布.各环境要素对TC、较弱类TC和较强类TC生成频数的影响有显著差异,相对湿度随着TC强度的增强而减弱,风速垂直切变则相反.西北太平洋TC频数年代际变化空间分布的正异常主要分布于130°E以东,(15°N,140°E)附近最大的正异常频数中心主要受绝对涡度和相对湿度正异常变化的影响;负的风速垂直切变和正的相对湿度异常变化引起了(10～15°N,160°E)附近的TC频数正异常. 相似文献
11.
DECADAL CHANGES IN WESTERN NORTH PACIFIC TROPICAL CYCLONES ASSOCIATED WITH MADDEN–JULIAN OSCILLATION
This study focuses on the decadal variability of tropical cyclones (TC) over the Western North Pacific (WNP) and how these changes are related to the Madden–Julian Oscillation (MJO). It was done with the help of the Real-time Multivariate MJO index from the Australian Government Bureau of Meteorology of the Centre for Australian Weather and Climate Research, TC data from the Joint Typhoon Warming Center best track datasets, and daily and monthly datasets from the NCEP/NCAR reanalysis center. The results show that the TC frequency in the WNP exhibited a statistically significant decrease during 1998–2010 compared to during 1979–1997. The decrease in TC frequency in the WNP mainly occurred during MJO active phases (i.e., phases 4, 5, 6, and 7). Further investigation of the climate background and the propagation differences of the MJO between 1979–1997 and 1998–2010 was performed. The La Ni?a-like tropical sea surface temperature cooling caused stronger Walker circulation and thus induced unfavorable atmosphere conditions for WNP TC genesis including a low-level easterly anomaly, a negative relative vorticity anomaly, an increase in sea-level pressure, and stronger vertical wind shear. Moreover, shortening of the MJO cycle, decline in the duration of the active phases in the WNP, and easterly anomaly and shrinkage of the convection area during MJO active phases may also partly explain the decadal variation of TC. 相似文献
12.
利用1979—2012年西北太平洋热带气旋最佳路径资料,Hadley中心的海温资料和NCEP/NCAR再分析资料等,研究了夏季(6—10月)热带北大西洋海温异常与西北太平洋热带气旋(Tropical Cyclone,TC)生成的关系及其可能机制。结果表明,夏季热带北大西洋海温异常与同期西北太平洋TC生成频次之间存在显著的负相关关系。热带北大西洋海温的异常增暖可产生一对东—西向分布的偶极型低层异常环流,其中气旋性异常环流位于北大西洋/东太平洋地区,反气旋异常环流位于西北太平洋地区。该反气旋环流异常使得TC主要生成区的对流活动受到抑制、低层涡度正异常、中低层相对湿度负异常、中层下沉气流异常,这些动力/热力条件均不利于TC生成。此外,西北太平洋地区低层涡旋动能负异常,同时来自大尺度环流的涡旋动能的正压转换也受到抑制,不能为TC的生成和发展提供额外能量源。反之亦然。 相似文献
13.
中国降水季节性的预估 总被引：2，自引：1，他引：1
本文使用国际耦合模式比较计划第五阶段（CMIP5）中共46个全球气候模式的数值试验数据,通过评估择优选取了14个模式来预估21世纪中国各季节降水百分率及其变率。结果表明,模式集合平均能够较好地模拟各季节降水百分率及其变率,但模式与观测间、各模式间都存在一定不同,空间上西部差异较大,季节上夏季差异明显。21世纪中国降水百分率整体表现为夏季大冬季小,但存在区域性,如华南春季降水百分率大于夏季。与1986~2004年相比,中国降水百分率整体表现为在夏季显著减少,冬春季显著增加,但高原则与之相反。此外,模式对于长江中下游地区降水百分率的预估存在较大不确定性。RCP8.5情景下降水季节性变幅要大于RCP4.5情景。降水季节性的变率在四季均表现出一定的增加趋势,但21世纪早、中和末期与1986~2004年相比并无显著差异（置信水平为95%）。 相似文献
14.
Water vapor transport and cross-equatorial flow over the Asian-Australia monsoon region simulated by CMIP5 climate models 总被引：1，自引：0，他引：1
The summer mean water vapor transport (WVT) and cross-equatorial flow (CEF) over the Asian-Australian monsoon region simulated by 22 coupled atmospheric-oceanic general circulation models (AOGCMs) from the World Climate Research Programme’s Coupled Model Intercomparison Project Phase 5 (CMIP5) were evaluated. Based on climatology of the twentieth-century simulations, most of models have a reasonably realistic representation of summer monsoon WVT characterized by southeast water vapor conveyor belt over the South Indian Ocean and southwest belt from the Arabian Sea to the East Asian. The correlation coefficients between NCEP reanalysis and simulations of BCC-CSM1-1, BNU-ESM, CanESM2, FGOALS-s2, MIROC4h and MPI-ESM-LR are up to 0.8. The simulated CEF depicted by the meridional wind along the equator includes the Somali jet and eastern CEF in low atmosphere and the reverse circulation in upper atmosphere, which were generally consistent with NCEP reanalysis. Multi-model ensemble means (MME) can reproduce more reasonable climatological features in spatial distribution both of WVT and CEF. Ten models with more reasonable WVT simulations were selected for future projection studies, including BCC-CSM1-1, BNU-ESM, CanESM2, CCSM4, FGOALS-s2, FIO-ESM, GFDL-ESM2G, MRIOC5, MPI-ESM-LR and NorESM-1M. Analysis based on the future projection experiments in RCP (Representative Concentration Pathway) 2.6, RCP4.5, RCP6 and RCP8.5 show that the global warming forced by different RCP scenarios will results in enhanced WVT over the Indian area and the west Pacific and weaken WVT in the low latitudes of tropical Indian Ocean. 相似文献
15.
CMIP5模式对冬季北极涛动的模拟和预估 总被引：1，自引：0，他引：1
基于NCEP/NCAR再分析资料和CMIP5的19个模式结果,从异常模态、年代际趋势和周期特征等方面评估了CMIP5耦合模式对冬季北极涛动(Arctic Oscillation,AO)的模拟能力,并对未来RCP4.5、RCP8.5两种浓度路径下AO的可能变化趋势给出了定性的预估。CMIP5模式历史试验结果显示,大多数模式都能够模拟出AO模态的基本结构,但是对中心位置、强度的模拟存在较大的偏差,其中MPI-ESM-LR和Had GEM2-AO能较好地模拟出AO整体模态来。在历史演变和周期特征的刻画方面,模式的冬季海平面气压经验正交函数分解第一模态时间序列(Principal Component,PC1)基本能够反映出1950~1970年以来的减弱趋势,但对1970年以后的增长趋势模拟并不明显,而北半球环状模指数(Zonal Index,ZI)序列对两个阶段的趋势均可模拟出来,模式的PC1和ZI序列总体表现为正的变化趋势。有一半以上的模式对2~3 a高频周期模拟较好,但对20 a左右的周期模拟较差,其中仅有Can ESM2、CNRM-CM5、GFDL-ESM2G这3个模式对ZI指数的两个周期变化模拟较好。在RCP4.5和RCP8.5两种浓度路径下,ZI序列有显著的上升趋势,从长期趋势系数看RCP4.5路径下有14个模式呈现正的变化趋势,其中有10个模式通过了检验。RCP8.5浓度路径下,16个模式为正变化趋势,有11个模式通过了检验,集合平均结果正变化趋势较为显著。两种浓度路径下不同时段的海平面气压变化趋势表明,ZI序列的年代际变化明显,存在3个不同的变化阶段——2006~2039年、2070~2100年为两个上升阶段,2040~2069年为缓慢下降阶段。 相似文献
16.
利用中国高空探空资料和NCEP/NCAR、ERA以及MERRA三种再分析资料,讨论了再分析资料风速场在中国区域的适用性问题。结果表明:在中国区域的年平均场上,高空风速在我国对流层高层和中层均存在长期减弱的趋势,在我国东部和南部地区的对流层低层也存在减弱趋势,ERA-interim资料和MERRA资料适用性相对较好。再分析资料风速在多年年平均场上普遍小于探空风速。在对流层高层,1980年代至1990年代ERA-interim资料适用性好,而21世纪以后,NCEP/NCAR的适用性较好;在对流层中层和低层,NCEP/NCAR资料适用性较好。在中国区域的季节平均场上,高空风速在冬季的对流层高层和中层中普遍存在增加的趋势,而在春季、夏季和秋季的对流层高层和中层存在减小的趋势。探空资料与再分析资料在冬季偏差最小,在夏季偏差最大。在对流层中层和低层,NCEP/NCAR资料和MERRA资料在冬季的可信度相对较好,MERRA资料在夏季的可信度相对较好;在对流层高层和平流层低层,ERA-interim资料和MERRA资料在四季中的可信度都相对较好。 相似文献
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利用中亚地区30个观测台站逐月降水资料及同期ERA-40再分析资料,结合8个CMIP5全球气候模式模拟与未来预估大尺度环流场,使用基于变形典型相关分析的统计降尺度方法（BP-CCA）建立降尺度模型,评估多个气候模式对当前气候下中亚地区春季降水的降尺度模拟能力,并对春季降水进行降尺度集合未来预估。结果表明,建立的降尺度模型能够很好地模拟出交叉检验期内春季降水的时间变化和空间结构：降尺度春季降水与相应观测序列的平均时间相关系数为0.35,最高为0.62,平均空间相关系数为0.87。气候模式对中亚春季降水的模拟能力通过降尺度方法得到了显著提高：8个模式降尺度后模拟的降水气候平均态相对误差绝对值降至0.2%—8%,相比降尺度前减小了10%—60%,模拟的降水量场与相应观测场的空间相关均超过0.77;对比降尺度前多模式集合结果,多模式降尺度集合模拟的相对误差绝对值由64%减小至4%,空间相关系数由0.47增大至0.81,标准化均方根误差降至0.59,且多模式降尺度集合结果优于大部分单个模式降尺度结果。多模式降尺度集合预估结果表明,在RCP4.5排放情景下,21世纪前期（2016—2035年）、中期（2046—2065年）和末期（2081—2100年）的全区平均降水变化率分别为-5.3%、3.0%和17.4%。21世纪前期中亚大部分地区降水呈减少趋势,降水呈增多趋势的站点主要分布在南部。21世纪中期整体降水变化率由减少变为增多趋势,21世纪末期中亚大部分台站降水增多较为明显。21世纪初期和末期可信度高的台站均主要位于中亚西部地区。 相似文献
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The middle and lower Yangtze River basin (MLYRB) suffered persistent heavy rainfall in summer 2020, with nearly continuous rainfall for about six consecutive weeks. How the likelihood of persistent heavy rainfall resembling that which occurred over the MLYRB in summer 2020 (hereafter 2020PHR-like event) would change under global warming is investigated. An index that reflects maximum accumulated precipitation during a consecutive five-week period in summer (Rx35day) is introduced. This accumulated precipitation index in summer 2020 is 60% stronger than the climatology, and a statistical analysis further shows that the 2020 event is a 1-in-70-year event. The model projection results derived from the 50-member ensemble of CanESM2 and the multimodel ensemble (MME) of the CMIP5 and CMIP6 models show that the occurrence probability of the 2020PHR-like event will dramatically increase under global warming. Based on the Kolmogorov–Smirnoff test, one-third of the CMIP5 and CMIP6 models that have reasonable performance in reproducing the 2020PHR-like event in their historical simulations are selected for the future projection study. The CMIP5 and CMIP6 MME results show that the occurrence probability of the 2020PHR-like event under the present-day climate will be double under lower-emission scenarios (CMIP5 RCP4.5, CMIP6 SSP1-2.6, and SSP2-4.5) and 3–5 times greater under higher-emission scenarios (3.0 times for CMIP5 RCP8.5, 2.9 times for CMIP6 SSP3-7.0, and 4.8 times for CMIP6 SSP5-8.5). The inter-model spread of the probability change is small, lending confidence to the projection results. The results provide a scientific reference for mitigation of and adaptation to future climate change. 相似文献
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This study investigates the influences of tropical Indian Ocean(TIO) warming on tropical cyclone(TC)genesis in different regions of the western North Pacific(WNP) from July to October(JASO) during the decaying El Nio. The results show significant negative TC frequency anomalies localized in the southeastern WNP. Correlation analysis indicates that a warm sea surface temperature anomaly(SSTA) in the TIO strongly suppresses TC genesis south of 21°N and east of 140°E in JASO. Reduced TC genesis over the southeastern WNP results from a weak monsoon trough and divergence and subsidence anomalies associated with an equatorial baroclinic Kelvin wave. Moreover,suppressed convection in response to a cold local SSTA, induced by the increased northeasterly connected by the wind-evaporation-SST positive feedback mechanism, is found unfavorable for TC genesis. Positive TC genesis anomalies are observed over higher latitudinal regions(at around 21°N, 140°E) and the western WNP because of enhanced convection along the northern flank of the WNP anomalous anticyclone and low-level convergence,respectively. Although local modulation(e.g., local SST) could have greater dominance over TC activity at higher latitudes in certain anomalous years(e.g., 1988), a warm TIO SSTA can still suppress TC genesis in lower latitudinal regions of the WNP. A better understanding of the contributions of TIO warming could help improve seasonal TC predictions over different regions of the WNP in years of decaying El Nio. 相似文献
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Connections Between the South Asian Summer Monsoon and the Tropical Sea Surface Temperature in CMIP5 下载免费PDF全文
下载免费PDF全文 The South Asian summer monsoon (SASM) precipitation is analyzed based on reanalysis datasets and historical simulation results from 23 climate models of the Coupled Model Intercomparison Project phase ... 相似文献