ENSO及印度洋海盆模态关联的南海SST异常年代际变化及海洋平流输送的贡献

采用国际海-气综合数据集（The International Comprehensive Ocean-Atmosphere Data Set, ICOADS）船舶观测资料及简单海洋同化分析数据（Simple Ocean Data Assimilation, SODA）, 研究了厄尔尼诺（El Nino-Southern Oscillation, ENSO）和印度洋海盆模态（Indian Ocean Basin, IOB）对南海海表温度（sea surface temperature, SST）影响的年代际变化, 并着重讨论了不同时期海洋平流输送对SST 异常的影响.结果表明, ENSO 事件对南海SST 的影响呈现显著的年代际变化特征;在1870-2007 年期间, 扣除资料较少的时期, 有4 个显著不同的时段, 分别是1892-1915 年、1930-1940 年、1960-1983年、1984-2007 年.在1950 年之前的两个时段, 南海在ENSO 期间出现一次显著的增暖, 而在1950 年之后的两个时段中, 南海出现了两次显著的增暖.除第一个时段外, 其余三个时段ENSO 发展期冬季大气潜热及短波辐射异常是导致南海增暖的主要原因, 海洋平流作用较弱; 而在最近的两个时段中, 海洋平流对ENSO 消亡年夏季南海增暖有重要影响.不同时段海洋平流对南海增暖贡献的差异说明ENSO 及IOB 对南海区域气候的影响具有明显的年代际变化特征.

Sea surface temperature anomalies in the South China Sea during mature phase of ENSO

Based on the 18-year （1993-2010） National Centers for Environmental Prediction optimum interpolation sea surface temperature （SST） and simple ocean data assimilation datasets, this study investigated the patterns of the SST anomalies （SSTAs） that occurred in the South China Sea （SCS） during the mature phase of the E1 Nifio/Southem Oscillation. The most dominant characteristic was that of the out- of-phase variation between southwestern and northeastern parts of the SCS, which was influenced primarily by the net surface heat flux and by horizontal thermal advection. The negative SSTA in the northeastern SCS was caused mainly by the loss of heat to the atmosphere and because of the cold-water advection from the western Pacific through the Luzon Strait during E1 Nifio episodes. Conversely, it was found that the anomalous large-scale atmospheric circulation and weakened western boundary current during E1 Nifio episodes led to the development of the positive SSTA in the southwestern SCS.

A NUMERICAL STUDY OF THE INFLUENCE OF SEA SURFACE TEMPERATURES WITH DIFFERENT TEMPORAL RESOLUTIONS ON TYPHOON DUJUAN OVER THE SOUTH CHINA SEA

Daily and weekly sea surface temperature data of Tropical Rainfall Measuring Mission (TRMM) Microwave Imager and Advanced Microwave Scanning Radiometer-Earth Observing System sensors are used as forcing of the underlying sea surface in the mesoscale numerical model to simulate Typhoon Dujuan that moved across the South China Sea in 2003. The numerical results show that different SSTs near the typhoon center result in differences in the atmospheric wind field, indicating that the model has a fast and obvious response to SSTs. Different SST influences the intensity and track of Dujuan to some degree and has significant impacts on its precipitation and latent heat flux near the eye. The SST influence on Dujuan is mainly fulfilled by changing the latent heat flux between the ocean surface and the atmosphere above.

Characteristics of Tropical Sea Surface Temperature Anomalies and Their Influences on the Onset of South China Sea Summer Monsoon

The characteristics of sea surface temperature anomalies （SSTAs） in the tropical oceans and their influences on the onset of South China Sea summer monsoon （SCSSM） have been studied.The anomaly of SST in tropical Pacific Ocean exerts persistence impact for one to three months on atmospheric circulations.If the warm pool becomes anomalously warmer during an earlier period from February to April,the SCSSM breaks out earlier,and vice versa.Singular value decomposition （SVD） and composite analysis have shown that,in La Ni（n）a pattern,the convection over Western Pacific will occur earlier and be stronger than normal,which favors the convergence at a lower layer over Western Pacific,as well as the strengthening of upwelling branch of Walker circulation,leading to an earlier burst of westerly in the southern South China Sea.Moreover,the convection in Sumatra appears earlier than normal and favors the westerly evolution in eastern Indian Ocean,resulting in the splitting of the subtropical high belt and an early onset of SCSSM.However,the atmospheric circulation anomaly is reversed in El Ni（n）o pattern.

The Different Effects of Sea Surface Temperature and Aerosols on Climate in East Asia During Spring

In this study, we used the NCAR CAM3.0 model to study the climate effects of both decadal global Sea Surface Temperature(SST) changing and the increasing aerosol concentration in East Asia in boreal spring. In the decadal SST changing experiment, a prominent sea surface cyclone anomaly occurred west of the Northwest Pacific warming SST. The cyclone anomaly is conductive to anomalous rising motion and more rainfall over the Northwest Pacific and southeast coast areas of China, but less rainfall in central China. Caused by the only aerosol concentration increasing, the change of climate in East Asia is totally different from that induced by the regime shift of SST around 1976/77 with the same model. The sulfate and black carbon aerosol concentrations were doubled respectively and synchronously in East Asia(20?–50?N, 100?–150?E) to investigate the climate effects of these two major aerosol types in three experiments. The results show that, in all three aerosol concentration changing experiments, the rainfall during boreal spring increases in North China and decreases in central China. It's worth noting that in the DTWO experiment, the rainfall diminishes in central China while it increases in the north and southeast coast areas of China, which is similar to observations. From the vertical profile between 110?E and 120?E, it is found that sulfate and black carbon aerosols first change the temperature of lower troposphere owing to their direct radiative effect, and then induce secondary meridional circulation anomaly through the different dynamic mechanisms involved, and at last generate precipitation and surface temperature anomalous patterns mentioned above.

Modeling the contribution of the microbial carbon pump to carbon sequestration in the South China Sea

The two key mechanisms for biologically driven carbon sequestration in oceans are the biological pump(BP) and the microbial carbon pump(MCP); the latter is scarcely simulated and quantified in the China seas. In this study, we developed a coupled physical-ecosystem model with major MCP processes in the South China Sea(SCS). The model estimated a SCSaveraged MCP rate of 1.55 mg C m^(-2) d^(-1), with an MCP-to-BP ratio of 1:6.08 when considering the BP at a depth of 1000 m.Moreover, the ecosystem responses were projected in two representative global warming scenarios where the sea surface temperature increased by 2 and 4°C. The projection suggested a declined productivity associated with the increased near-surface stratification and decreased nutrient supply, which leads to a reduction in diatom biomass and consequently the suppression of the BP. However, the relative ratio of picophytoplankton increased, inducing a higher microbial activity and a nonlinear response of MCP to the increase in temperature. On average, the ratio of MCP-to-BP at a 1000-m depth increased to 1:5.95 with surface warming of 4°C, indicating the higher impact of MCP in future ocean carbon sequestration.