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1.
1998年南海西南季风活动的初步分析 总被引：11，自引：3，他引：8
利用NCEP再分析资料和OLR、SST观测数据,分析了1998年南海西南季风的建立日期、强度的多时间尺度变化特征、与海面温度的相互作用以及对广东降水的影响.得出南海西南季风建立的日期为5月17日(5月4候).1998年为弱季风年,OLR具有1个月左右的振荡周期,西南风具有半个月左右的振荡周期.孟加拉湾地区季风和105°E越赤道气流是南海季风低频变化的重要策源地.1998年南海季风弱,主要是由于初春赤道东太平洋海温正距平,并导致南海-阿拉伯海海温正距平的结果. 相似文献
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南海夏季风活动的年际和年代际特征 总被引：40，自引：1，他引：40
利用NCEP风场资料和候平均向外长波辐射（OLR）资料分析了南海区域低层风场与对流活动的关系,在此基础上,采用南海中南部的纬向风平均值来定义南海夏季风的爆发,确定了长序列（1949～1998）的南海夏季风爆发日期和强度指数,并研究南海夏季风活动的年际和年代际变化特征。结果表明：南海夏季风爆发日期和强度指数呈显著的反相关;50年来的气候趋势是,爆发日期逐渐偏晚,强度指数逐渐减弱。二者都存在着明显的年际和年代际变化,它们在不同阶段上的波动是各种时间尺度振荡叠加的结果,而年代际尺度具有非常重要的作用。东印度洋海温异常在南海夏季风爆发前后,均与南海夏季风强度指数呈显著的反相关。东太平洋海温异常在南海夏季风爆发之前,与强度指数反相关,而爆发之后,与强度指数正相关。这体现了南海夏季风活动与ENSO事件的密切关系。 相似文献
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The influence of the biweekly sea surface temperature (SST) in the South China Sea (SCS) on the SCS summer monsoon, especially during the Indian Ocean Dipole (IOD) is presented using the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) SST and rainfall data for April to June from 1999 to 2013. During positive IOD (PIOD) years the biweekly SST anomalies over the SCS lead the rain anomalies by three days, with a significant correlation (r?=?0.8, at the 99% confidence level), whereas during negative IOD (NIOD) years, the correlation is only 0.2. The biweekly SST is observed to influence the westward and northward propagating rainfall anomalies over the SCS and, hence, affect the SCS summer monsoon, especially during PIOD years. No such propagation was seen during NIOD years. The biweekly intraseasonal oscillation of SST in the SCS results in enhanced sea level pressure and surface shortwave radiation, especially during PIOD years. The potential findings here indicate that the biweekly SST in the SCS is strongly (weakly) influenced during PIOD (NIOD) years. Further, it is observed that SST in the SCS has a strong (weak) effect on the SCS summer monsoon by westward and northward propagation of rainfall, especially during PIOD (NIOD) years. When a PIOD or NIOD exists over the tropical Indian Ocean, the SCS SST will be strongly (r?=?0.6, at the 99% confidence level) or weakly correlated with the residual index, respectively. 相似文献
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Based on 1948 - 2004 monthly Reynolds Sea Surface Temperature (SST) and NCEP/NCAR atmospheric reanalysis data, the relationships between autumn Indian Ocean Dipole Mode (IODM) and the strength of South China Sea (SCS) Summer Monsoon are investigated through the EOF and smooth correlation methods. The results are as the following. (1) There are two dominant modes of autumn SSTA over the tropical Indian Ocean. They are the uniformly signed basin-wide mode (USBM) and Indian Ocean dipole mode (IODM), respectively. The SSTA associated with USBM are prevailing decadal to interdecadal variability characterized by a unanimous pattern, while the IODM mainly represents interannual variability of SSTA. (2) When positive (negative) IODM exists over the tropical Indian Ocean during the preceding fall, the SCS summer monsoon will be weak (strong). The negative correlation between the interannual variability of IODM and that of SCS summer monsoon is significant during the warm phase of long-term trend but insignificant during the cool phase. (3) When the SCS summer monsoon is strong (weak), the IODM will be in its positive (negative) phase during the following fall season. The positive correlation between the interannual variability of SCS summer monsoon and that of IODM is significant during both the warm and cool phase of the long-term trend, but insignificant during the transition between the two phases. 相似文献
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1998年南海夏季风低频振荡特征分析 总被引：9，自引：8，他引：9
利用NCEP/NCAR1998年再分析资料和SST资料，研究了南海夏季风的低频振荡特征。结果表明，南海夏季风的低频振荡对南海夏季风的爆发具有加强的作用；南海低频低层辐合（散）区对应低频降水正（负）值区；南海地区的大气低频振荡以向北、向东传播为主，南海地区低频散度在垂直方向呈现出相互补偿的特征。 相似文献
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利用NCEP/NCAR(美国国家环境预报中心/国家大气研究中心)再分析资料,对南海强夏季风年和弱夏季风年进行合成分析,结果表明,无论是在夏季风爆发前的1月份或是夏季风盛行的7月份,强弱夏季风年的平均经圈环流和平均纬圈环流都有明显差异。在强夏季风年,1月份的哈特莱环流、7月份的瓦克环流和季风经圈环流都比弱夏季风年同期的明显。强夏季风年的西太平洋副热带高压比弱夏季风年明显偏弱。利用OLR资料分析强夏季风年(1981年)和弱夏季风年(1983)4～9月份赤道东印度洋和南海对流活动的季节内振荡,发现在南海强夏季风年,季节内振荡的次数偏少而强度偏强,在弱夏季风年,季节内振荡的次数偏多而强度偏弱。相比之下,在南海强夏季风年,赤道东印度洋的季节内振荡比南海的更具典型性。 相似文献
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Renguang Wu 《Climate Dynamics》2010,34(5):629-642
Analysis of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) data for the period 1998–2007 reveals large
subseasonal fluctuations in sea surface temperature (SST) of the South China Sea during the summer monsoon onset. These subseasonal
SST changes are closely related to surface heat flux anomalies induced by surface wind and cloud changes in association with
the summer monsoon onset. The SST changes feed back on the atmosphere by modifying the atmospheric instability. The results
suggest that the South China Sea summer monsoon onset involves ocean–atmosphere coupling on subseasonal timescales. While
the SST response to surface heat flux changes is quick and dramatic, the time lag between the SST anomalies and the atmospheric
convection response varies largely from year to year. The spatial–temporal evolution of subseasonal anomalies indicates that
the subseasonal variability affecting the South China Sea summer monsoon onset starts over the equatorial western Pacific,
propagates northward to the Philippine Sea, and then moves westward to the South China Sea. The propagation of these subseasonal
anomalies is related to the ocean–atmosphere interaction, involving the wind-evaporation and cloud-radiation effects on SST
as well as SST impacts on lower-level convergence over the equatorial western Pacific and atmospheric instability over the
Philippine Sea and the South China Sea. 相似文献
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CHARACTERISTICS OF FREQUENCY SPECTRUM VARIATION OF INTRASEASONAL OSCILLATION OF CONVECTION DURING SOUTH CHINA SEA SUMMER MONSOON 总被引：1，自引：1，他引：1
1 INTRODUCTIONSituated in the region of East Asian Monsoon(EAM), weather and climate in China are deeplyinfluenced by the activities of EAM. Especially inflood seasons, distribution of precipitation, movementof rain-bands and occurrence of droughts and fl… 相似文献
11.
Datasets of equivalent temperature of black body (TBB) and sea surface temperature (SST)
ranging from 1980 to 1997 are used to diagnose and analyze the characteristics of frequency spectrum and
strength of intraseasonal variation of convection. The relationship between the strength of intraseasonal
oscillation of convection, strength of convection itself and SST in the South China Sea (SCS) is studied. It is
shown that, there are distinguishable annual, interannual and interdecadal variations in both strength and
frequency spectrum of intraseasonal variation of convection in SCS. There are connections between strength of
convection, strength of ISO1 in the summer half (s.h.) year and SST in ensuing winter half (w.h.) year in SCS.
The strong (weak) convection and strong (weak) ISO1 are associated with negative (positive) bias of SST in
ensuing w.h. year in SCS. 相似文献
12.
Summer Monsoon Impacts on Chlorophyll-a Concentration in the Middle of the South China Sea: Climatological Mean and Annual Variability 
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下载免费PDF全文 Climatological mean and annual variations of Chlorophyll-a(Chl-a) distribution,sea surface wind(SSW),and sea surface temperature(SST) from 1998 to 2008 were analyzed in the middle of the South China Sea(SCS),focusing on the typical region off the east coast of Vietnam(8.5-14°N,109.5-114°E).Based on remote sensing data and SCS summer monsoon index(SCSSMI) data,high Chl-a concentrations in the middle of the SCS in the southwest summer monsoon season(June-September) may be related to strong Ekman pumping and strong wind stress.The maximum of the monthly averaged climatological Chl-a in the summer appeared in August.According to the annual variation,there was a significant negative correlation(r =-0.42) between the SCSSMI and SST,a strongly positive correlation(r=0.61) between the SCSSMI and Chl-a,and a strongly negative correlation(r =-0.74) between the SST and Chl-a in the typical region off the east coast of Vietnam during 1998-2008.Due to the El Ni?o event specifically,the phenomena of a low Chl-a concentration,high SST and weak SCSSMI were extremely predominant in the summer of 1998.These relationships imply that the SCSSMI associated with the SST could be used to predict the annual variability of summer Chl-a in the SCS. 相似文献
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Influence of sea surface temperature on the intraseasonal variability of the South China Sea summer monsoon 总被引：6，自引：4，他引：2
The objective of this study is to examine, based on recently available high resolution satellite and observational data, the evolution and role of sea surface temperature (SST) in influencing the intraseasonal variability of the South China Sea (SCS) summer monsoon (SM). The study focuses on the 30–60?day timescale when the northward propagating anomalies are dominant over the SCS. Composite analysis of the SST maximum events during SCS SM shows that increased SST anomalies over the SCS are significantly influenced by the downward shortwave radiation flux anomalies, with the suppressed surface latent heat flux anomalies supplementing to it. A thermal damping of the positive SST anomalies induces positive upward heat fluxes, which then destabilize the lower atmosphere between 1,000 and 700?hPa. The positive SST anomalies lead the positive precipitation anomalies over the SCS by 10?days, with a significant correlation (r?=?0.44) between the SST-precipitation anomalies. The new findings here indicate an ocean-to-atmosphere effect over the SCS, where underlying SST anomalies tend to form a favorable condition for convective activity and sustain enhanced precipitation during the SCS SM. It is also argued, based on our observations, that the negative sea level pressure anomalies induced by the positive SST anomalies play a role in enhancing the northward propagation of the intraseasonal anomalies over the SCS. 相似文献
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1INTRODUCTIONLocatingatthesoutheasternpartofAsia,theSouthChinaSea(SCS)linkstheIndianOceanandwesternPacificandimmediatelyborderswiththeSouthAsiamonsoonregion.ItisanimportantlocationinwhichtheEastAsiamonsoonsysteminteractswiththeIndianOceanoneandamostdirectsourceofmoistureforthesubtropicalmonsoonsysteminEastAsia.TheSCSmonsoonanomaliescandirectlyaffectonthetemporal-spatialdistributionofprecipitationinthesouthofChinaandtheChangjiangRivervalleysothatseriousfloods/droughtsarecaused.Com… 相似文献
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利用NCEP再分析资料和OLR、SST观测数据, 研究了南海地区西南季风的多时间尺度变化特征, 对比分析了强弱西南季风年大气环流的差异. 南海西南季风的强弱变化与海表面温度 (SST) 之间存在显著的相互作用, 年际或以上时间层次变化主要表现为南海西南季风强弱与东太平洋海温、南海-阿拉伯海海温存在显著负相关.对月季时间层次, 东太平洋海温变化对西南季风强度变化的影响仍起重要作用, 南海-阿拉伯海海温与西南季风之间相互作用不但表现为西南季风对海温的作用 (西南季风强 (弱) 导致后期海温降低 (升高)), 同时海温变化对西南季风也起相当重要的作用, 前期海温正 (负) 距平有利于西南季风增强 (减弱). 相似文献
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在对南海夏季风的爆发及中南半岛陆面过程的可能影响进行了诊断分析的基础上,应用MM5/NOAHLSM模式,研究了中南半岛陆气相互作用对2004年南海夏季风爆发过程的可能影响。结果发现:在南海夏季风爆发前,中南半岛南海地区低层气温差确实出现低值,甚至负值;尽管短期内中南半岛土壤湿度和降水的变化没有引起季风爆发日期的改变,但对季风爆发的强度有影响。土壤湿度和降水变化引起的干异常可导致地表感热通量的增大和地表温度的升高,致使中南半岛与南海之间低层的温差异常(负温差)减小,季风爆发强度减弱;不同的是,湿异常可引起季风爆发强度增强。这一结果说明,在南海夏季风爆发前期,中南半岛上空对流活动和降水异常及其引起的土壤湿度的异常变化在一定程度上会影响到季风爆发的过程。文章还比较了不同温湿地表条件下低层大气状态的差异和地表能量、水分平衡过程的不同,分析了陆气相互作用对季风活动产生影响的物理机制。 相似文献
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NUMERICAL SIMULATION EXPERIMENTS OF THE IMPACTS OF LOCAL LAND-SEA THERMODYNAMIC CONTRASTS ON THE
SCS SUMMER MONSOON ONSET 总被引：1，自引：0，他引：1
1INTRODUCTIONAmongdrivingfactorsfortheEastAsianmonsoonareplanetary-scaleland-seathermodynamiccontrast(e.g.betweentheEurasiancontinentandthePacificOcean)andsub-planetary-scaleone(e.g.betweentheIndochinaandtheSouthChinaSea).ItisovertheSouthChinaSea(SCS)andadjoiningareasthattheEastAsiansummermonsoonfirstbreaksout.ItthenadvancestotheregionsofEastAsiaandSouthAsia.ItisthereforenaturaltofindlocalgeographicandtopographiceffectsoftheSCSregionevidentlyshownontheonsetoftheSCSsummermonsoon… 相似文献
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基于1980—2018年罗格斯大学全球积雪实验室积雪面积、英国气象局哈得来中心海温、欧洲中期天气预报中心（ECMWF）第5代再分析（ERA-5）土壤湿度、美国国家环境预报中心和美国国家大气研究中心（NCEP/NCAR）再分析、美国国家海洋大气管理局（NOAA）气候预测中心降水（CMAP）和全球降水气候计划降水（GPCP）等数据,采用相关、合成和回归等分析方法,分析了前期青藏高原积雪和厄尔尼诺-南方涛动（ENSO）年际尺度变化对南海夏季风强度及降水的协同影响。结果表明:在年际尺度上,青藏高原积雪、ENSO与南海夏季风变率有密切关系,当青藏高原春季积雪西部偏多且东部偏少时,夏季高原西部对流层温度偏低,在高原上空产生异常下沉气流并向外辐散,引起中国南海地区对流层中低层为异常下沉气流。另外,赤道中东太平洋海温异常偏高则会使夏季印度洋海温异常偏高,对流层温度偏高,在西北太平洋产生东北风异常,加强西北太平洋和中国南海上空的反气旋性环流异常。在青藏高原积雪和ENSO共同影响下,夏季850 hPa中国南海上空反气旋异常进一步加强,南海夏季风强度减弱,降水减少。 相似文献
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不同资料揭示南海夏季风爆发特征的比较 总被引：3，自引：1，他引：3
利用全球月平均海温资料，近地面的风、气温、湿度资料，以及海表感热和潜热资料，在综合分析海温和气象要素变化的基础上，确定了7个全球海气相互作用的关键区，并运用相关分析法，着重分析了各关键海区上空气象要素场与海温的时滞相关，以揭示不同关键海区海气相互作用的异同。分析表明：不同海区海气热力相互作用较强，海温与气温比湿有较好的互代性，特别是中东太平洋和南印度洋海区。动力作用对海温的影响各海区差异较大，中西太平洋海区的动力影响可能更关键。在感热潜热与海温的相关中，东西太平洋海区和西北太平洋及南印度洋两季风区都较关键。通过分析各海区海温和各气象要素相邻月的持续相关概率，进一步了解哪些要素、哪些区在哪些时段其异常持续性好，或异常持续性容易发生破坏，这不仅对做预报有一定的参考价值，也为我们讨论海气相互作用的物理机制提供了依据。 相似文献
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利用南海季风试验分析场和NCAR向外长波辐射通量(OLR)资料研究了1998年孟加拉湾季风和南海季风爆发期间副热带环流的大尺度和天气尺度特征,探讨了孟加拉湾季风爆发与南海季风爆发之间的物理联系及孟加拉湾季风气旋的对流凝结潜热释放对副热带高压“撤出”南海的影响。结果表明,1998年5月爆发的东亚季风展现出典型的从孟加拉湾地区东传发展到南海地区的过程。随着孟加拉湾季风爆发和对流活动增强、北移,南海北部出现了低层西风和对流活动,领先于副热带高压在南海地区减弱和撤退。结果还显示南海北部地区的对流凝结加热有助于该地区经向温度梯度的反转,在热成风关系的制约下南海上空副热带高压脊面的垂直倾斜由冬季型转向夏季型,季风爆发。 相似文献