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1.
The trends of the sea surface temperature(SST) and SST fronts in the South China Sea(SCS) are analyzed during2003–2017 using high-resolution satellite data. The linear trend of the basin averaged SST is 0.31°C per decade,with the strongest warming identified in southeastern Vietnam. Although the rate of warming is comparable in summer and winter for the entire basin, the corresponding spatial patterns of the linear trend are substantially different between them. The SST trend to the west of the Luzon Strait is characterized by rapid warming in summer, exceeding approximately 0.6°C per decade, but the trend is insignificant in winter. The strongest warming trend occurs in the southeast of Vietnam in winter, with much less pronounced warming in summer. A positive trend of SST fronts is identified for the coast of China and is associated with increasing wind stress. The increasing trend of SST fronts is also found in the east of Vietnam. Large-scale circulation, such as El Ni?o, can influence the trends of the SST and SST fronts. A significant correlation is found between the SST anomaly and Ni?o3.4 index, and the ENSO signal leads by eight months. The basin averaged SST linear trends increase after the El Ni?o event(2009–2010), which is, at least, due to the rapid warming rate causing by the enhanced northeasterly wind. Peaks of positive anomalous SST and negatively anomalous SST fronts are found to co-occur with the strong El Ni?o events.  相似文献   

2.
The annual, interannual and inter-decadal variability of convection intensity of South China Sea (SCS) summer monsoon and air-sea temperature difference in the tropical ocean is analyzed, and their relationship is discussed using two data sets of 48-a SODA (simple ocean data assimilation) and NCEP/NCAR. Analyses show that in wintertime Indian Ocean (WIO), springtime central tropical Pacific (SCTP) and summertime South China Sea-West Pacific (SSCSWP), air-sea temperature difference is significantly associated with the convection intensity of South China Sea summer monsoon. Correlation of the inter-decadal time scale (above 10 a) is higher and more stable. There is inter-decadal variability of correlation in scales less than 10 a and it is related with the air-sea temperature difference itself for corresponding waters. The inter-decadal variability of the convection intensity during the South China Sea summer monsoon is closely related to the inter-decadal variability of the general circulation of the atmosphere. Since the late period of the 1970s, in the lower troposphere, the cross-equatorial flow from the Southern Hemisphere has intensified. At the upper troposphere layer, the South Asian high and cross-equatorial flow from the Northern Hemisphere has intensified at the same time. Then the monsoon cell has also strengthened and resulted in the reinforcing of the convection of South China Sea summer monsoon.  相似文献   

3.
Using the National Center for Enviromental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data and NOAA satellite-obser ved outgoing long-wave radiation (OLR) data, the development of the South China Sea (SCS) summer monsoon and intraseasonal (30-60 d) oscillation (ISO) have been examined. The results show that there exists obvious interannual variability of intraseasonal oscillaiton. Using the 16 a time series of filtered OLR averaged over the SCS, an index is defined to define ““onset events““ over the SCS on the ISO time scales. Of the 16 a examined here, 10 shows a strong ISO signal in the onset of monsoon convection over the SCS. In these cases, the ISO initially suppresses the seasonal development of southwesterly and cyclonic circulation over the SCS before the ISO onset. As the ISO propagates northeastward, the low frequency cyclonic circulation anomaly occurs in the SCS and the low frequency southwesterly wind and convection over here dramatically intensify. The northeast progression of the ISO anomaleis plays a role in the initial suppression and then acceleration of the seasonal cycle of the SCS summer monsoon.  相似文献   

4.
Variations of monsoon wind field in the sea area along the southeastern coast of China during the ENSO events and its influence on the sea level and sea surface temperature (SST) are explored mainly on the basis of the data of monthly mean wind at 850 hPa and five coastal stations during 1973-1987. The results from the analyses of the data and theoretical estimation show that the southwest wind anomalies appeared in the study area during the events, and northeast wind anomalies occurred in general before the events. With the coastline of the area being parallel basically to the direction of the wind, an Ekman transport will result in an accumulation of the water near the coast or a departure of the water from the coast. As a result , the sea level and SST there will be affected markedly. During the events, southwest wind will intensify in the summer, and northeast wind will weaken in the winter. Their total effect is that a large negative anomaly of the sea level and SST will occur. The estimations indi  相似文献   

5.
南海沿海季节性海平面异常变化特征及成因分析   总被引:1,自引:1,他引:0  
Based on sea level, air temperature, sea surface temperature(SST), air pressure and wind data during 1980–2014,this paper uses Morlet wavelet transform, Estuarine Coastal Ocean Model(ECOM) and so on to investigate the characteristics and possible causes of seasonal sea level anomalies along the South China Sea(SCS) coast. The research results show that:(1) Seasonal sea level anomalies often occur from January to February and from June to October. The frequency of sea level anomalies is the most in August, showing a growing trend in recent years. In addition, the occurring frequency of negative sea level anomaly accounts for 50% of the total abnormal number.(2) The seasonal sea level anomalies are closely related to ENSO events. The negative anomalies always occurred during the El Ni?o events, while the positive anomalies occurred during the La Ni?a(late El Ni?o) events. In addition, the seasonal sea level oscillation periods of 4–7 a associated with ENSO are the strongest in winter, with the amplitude over 2 cm.(3) Abnormal wind is an important factor to affect the seasonal sea level anomalies in the coastal region of the SCS. Wind-driven sea level height(SSH) is basically consistent with the seasonal sea level anomalies. Moreover, the influence of the tropical cyclone in the coastal region of the SCS is concentrated in summer and autumn, contributing to the seasonal sea level anomalies.(4) Seasonal variations of sea level, SST and air temperature are basically consistent along the coast of the SCS, but the seasonal sea level anomalies have no much correlation with the SST and air temperature.  相似文献   

6.
The variability of the sea surface temperature(SST) in the China seas has been studied in seasonal,interannual and interdecadal scales based on the monthly data of HadISST spanning from 1870 to 2007. The main results obtained are SST in the China offshore changes most actively at the seasonal scale with the intensity diminishing from north to south,as the temperature differences between summer and winter reaching 17 and 4 C in the northern and southern areas,respectively. Moreover,seasonal variation near the coastal regions seems relatively stronger than that far from the coastline;significant interannual variations are detected,with the largest positive anomaly occurring in 1998 in the overall area. But as far as different domains are concerned,there exists great diversity,and the difference is also found between winter and summer. Differed from the seasonal variations,where the strongest interannual variability takes place,resides to the south of that of the seasonal ones in the northern section,nevertheless in the South China Sea,the most significant interannual variability is found in the deep basin;interdecadal changes of summer,winter and annual mean SST in different domains likewise present various features. In addition,a common dominant warming in recent 20 a are found in the overall China offshore with the strongest center located in the vicinity of the Changjiang Estuary in the East China Sea,which intensifies as high as 1.3 C during the past 130 a.  相似文献   

7.
SST Rhythm and Long-range Sea-ice Forecast   总被引:1,自引:0,他引:1  
In this note, the rhythm of sea surface temperature (SST) is studied. It is found thatover the North Pacific the summer (July to October), SST correlates well with the SST inwinter (January to March), which is called SST rhythm. It is shown that the SST rhythm links the summer SST in the North Pacific with thewinter sea--ice in the Bohai Sea. This relationship may be used to make long--range sea-ice prediction. Unfortunately the available series of sea--ice is too short. But the experience  相似文献   

8.
In order to quantitatively estimate the volume and property transports between the South China Sea and Indonesian Seas via the Karimata Strait, two trawl-resistant bottom mounts, with ADCPs embedded, were deployed in the strait to measure the velocity profile as part of the South China Sea-Indonesian Seas transport/exchange (SITE) program. A pair of surface and bottom acoustic modems was employed to transfer the measured velocity without recovering the mooring. The advantage and problems of the instruments in this field work are reported and discussed. The field observations confirm the existence of the South China Sea branch of Indonesian throughflow via the Karimata Strait with a stronger southward flow in boreal winter and weaker southward bottom flow in boreal summer, beneath the upper layer northward (reversal) flow. The estimate of the averaged volume, heat and freshwater transports from December 2007 to March 2008 (winter) is (-2.7 ± 1.1) × 10 6 m3/s, (-0.30 ± 0.11) PW, (-0.18 ± 0.07) × 106m3/s and from May to September 2008 (summer) is (1.2 ± 0.6) × 106m3/s, (0.14 ± 0.03) PW, (0.12 ± 0.04) × 106m3/s and for the entire record from December 2007 to October 2008 is (-0.5 ± 1.9) × 10 6 m3/s, (-0.05 ± 0.22) PW, (-0.01 ± 0.15) × 106m3/s (negative/positive represents southward/northward transport), respectively. The existence of southward bottom flow in boreal summer implies that the downward sea surface slope from north to south as found by Fang et al. (2010) for winter is a year-round phenomenon.  相似文献   

9.
On the basis of hydrographic data obtained in August 2000 cruise, the circulation in the South China Sea (SCS) is computed by the modified inverse method in combination with SSH data from TOPEX/ERS-2 analysis. For study of the dynamical mechanism, which causes the pattern of summer circulation in the SCS, the diagnostic model (Yuan et al. 1982. Acta Oceanologica Sinica,4(1):1-11; Yuan and Su. 1992. Numerical Computation of Physical Oceanography.474-542) is used to simulate numerically the summer circulation in the SCS. The following results  相似文献   

10.
A correlation analysis is performed to investigate the relationship between El Nino-Southern Oscillation (ENSO) and the Antarctic oscillation (AAO) at the quasi-quadrennial (QQ) timescale.It is found that the cold tongue index (CTI) and the AAO index (AAOI) are negatively correlated with about a 7-month lead-time,while they are positively correlated with about a 15-month lag-time.To further explore this relationship,complex empirical orthogonal function analysis is employed in the QQ sea level pressure (SLP) anomalies from 1951 to 2002.The results indicate that,during the ENSO cycle,there exists one kind of global tropical wave of wavenumber 1 (GTW1) propagating eastward.With the traveling of GTW1,the tropical SLP anomaly tends to intrude into the southern mid-latitudes.Accordingly,three strong signals travel synchronously along the circumSouth-Pacific path,and a relatively weak signal extends eastward and poleward over the South Ocean in the Atlantic-Indian Ocean sector.Following the propagation of these signals,the AAO phase tends to be reversed progressively.As a result,there exists an evident lead-lag correlation between CTI and AAOI.It can be concluded that ENSO plays a key role in the phase transition of AAO at the QQ timescale.It is also noticed that this regular relationship is only evident in the canonical ENSO events,for which sea surface temperature (SST) anomalies extend westward from the tropical eastern Pacific.On the other hand,the similar relationships are not found among those atypical ENSO events for which SST anomalies spread eastward from the central Pacific,such as the 1982-1983 ENSO event.  相似文献   

11.
用南海西沙站观测资料诊断研究南海季风季节内振荡   总被引:1,自引:0,他引:1  
应用Lanczos滤波和小波变换方法,对1958~2000年南海北部西沙站降水和1980~2001年850hPa风场观测资料进行分析,发现西沙站每日降水和850hPa风场都存在谱长度10~50d左右其峰值为10~20,30~50d的季节内振荡,降水和850hPa风场的季节内振荡都有明显的年变化.降水季节内振荡开始于5月中旬结束于10月中旬,与南海夏季风的爆发时间和终止时间一致.850hPa风场谱长度10~50d左右其峰值为10~20,30~50d的季节内振荡在一年中的大部分时间都存在.降水和850hPa风场季节内振荡的强弱年与南海夏季风的强弱年并不一致.研究表明南海夏季风存在季节内振荡,而南海夏季风与季节内振荡的关系比较复杂.  相似文献   

12.
应用广东境内分布较均匀的20个测站的降水资料,分析了E1Nino事件与广东各区域夏季(本文指5—8月,下同)降水的关系,以及赤道东太平洋海温、南海海温的变化对广东夏季降水的影响,并探讨了E1Nino事件与广东各区域历史旱涝的关系。结果表明,把广东看为一个整体,E1Nino事件与其夏季旱涝关系不明显。但把广东划分为西北部、东北部、中部及西南部,则在E1Nino事件当年,西北部偏旱,西南部偏涝;在E1Nino事件次年,西北部偏涝,西南部偏旱;而东北部及中部在E1Nino事件当年和次年雨量均偏多,但当年比次年的偏多率大。  相似文献   

13.
有孔虫在生长发育过程中能够捕获或黏附周围海水中的钙质或硅质形成自己的壳体,因此有孔虫的地球化学特征能够记录古气候、古海洋和古环境信息。以2017年蛟龙号第136潜次在南海珍贝海山底部约2500 m水深位置精准采集的柱状样品为研究对象,对其中的G.ruber以及G.sacculifer两类浮游有孔虫壳体的Mg/Ca以及碳氧同位素组成进行了分析测试。结果表明自12.6 ka以来该海域表层海水温度(SST)的变化范围为24.4~29.3℃,平均温度为26.2℃,并能够识别出明显的气候突变事件,在时间范围上与新仙女木事件和全新世东亚夏季风突变事件大致吻合。这些突变事件可能受控于ENSO活动和热带辐合带(ITCZ)平均位置的纬向移动,并与北大西洋冰筏事件具有遥相关。此外,发现全新世期间浮游有孔虫G.sacculifer和G.ruber的碳同位素分馏值Δ^13CG.sacculifer-G.ruber与SST变化有关,SST降低时,Δ^13CG.sacculifer-G.ruber呈负偏;而在SST升高时,Δ^13CG.sacculifer-G.ruber呈正偏。  相似文献   

14.
利用零降水日对广东沿海夏季降水的年代际变化成因进行统计相关分析,结果表明:南海表层海温(SST)对次年夏季广东沿海地区降水有明显影响,并且这种影响作用在20世纪70年代有一个明显的年代际变异;南海SST影响广东省夏季降水的敏感区域在不同的年代际阶段都非常靠近广东省,局地性非常明显。局地的海气相互作用对广东沿海夏季降水的短期气候预测有显著的意义。  相似文献   

15.
Changes and fluctuations in sea surface temperature (SST) around the South African coast are analysed at a monthly scale from 1982 to 2009. There is a statistically significant negative trend of up to 0.5 °C per decade in the southern Benguela from January to August, and a cooling trend of lesser magnitude along the South Coast and in the Port Elizabeth/Port Alfred region from May to August. The cooling is due to an increase in upwelling-favourable south-easterly and easterly winds. There is a positive trend in SST of up to 0.55 °C per decade in most parts of the Agulhas Current system during all months of the year, except for KwaZulu-Natal where warming is in summer. The warming was attributed to an intensification of the Agulhas Current in response to a poleward shift of westerly winds and an increase in trade winds in the South Indian Ocean at relevant latitudes. This intensification of the Agulhas Current could also have contributed to the coastal cooling in the Port Alfred dynamic upwelling region. The El Niño Southern Oscillation (ENSO) is significantly positively correlated at a 95% level with the southern Benguela and South Coast from February to May, and negatively correlated with the Agulhas Current system south of 36° S. The correlation with the Antarctic Annular Oscillation is weaker and less coherent. El Niño suppresses upwelling along the coast, whereas La Niña increases it. Although there does not seem to be a linear relationship between the strength of the ENSO and the magnitude of coastal SST perturbation, El Niño and La Niña appear to be linked to major warm and cool events, respectively, at a seasonal scale in summer in the southern Benguela and along the South Coast. However, care must be taken in interpreting low-resolution reanalysed climate data (ERA40 and NCEP) and optimally interpolated Reynolds SST, such as used here.  相似文献   

16.
1Introduction Indian Ocean dipole(IOD),a kind of localcharacteristics of variation of sea surface temperature(SST)in the Indian Ocean,behaves with an oppo-site SSTA symbol between the east and west parts ofthe tropical Indian Ocean(Yu and Liu,2004;Rongand…  相似文献   

17.
根据观测资料和海气耦合模式初值试验结果,通过比较分析热带太平洋SST主模态(ENSO模)和热带印度洋SST主模态(海盆模)对夏季南亚高压的影响,揭示了印度洋海盆模的"充电/放电"作用:赤道中东太平洋海温异常首先对印度洋进行"充电",形成热带印度洋SST对太平洋EN-SO的响应模态——海盆模。该模态在ENSO发生翌年春季达到峰值位相,而且有很好的持续性,可以从春季持续到夏季,该暖(冷)模态可以引起大气的"Matsuno-Gillpattern"响应,并通过亚洲夏季平均西南季风的异常水汽输送等使得夏季南亚高压偏强(弱),即为"放电"过程。而赤道中东太平洋海温异常对夏季南亚高压的直接影响并不显著,并指出了夏季南亚高压和超前3~12个月Nio3指数之间高的显著正相关关系只是一个表象,并不是太平洋海温异常对南亚高压的直接影响结果,而是通过印度洋海盆模态的"充电/放电"作用引起的。  相似文献   

18.
Having been calculated and analysed, it is found in this research paper that there exist a close lag relationship between sea surface temperature (SST) change in the north of the North Atlantic and height change at 500 hPa level in South Asia. In this paper, it is focused on the analysis of physical processes of the relation between SST and height and their effect on summer monsoon in South Asia.  相似文献   

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