南海18°N断面中层水的年代际变化     

赵德平  王卫强  覃慧玲  毛庆文  王东晓  陈荣裕 《海洋学报》2014,36(9):56-64

利用中国科学院南海海洋研究所历史温盐剖面观测资料和WOD09(World Ocean Database2009)中的CTD、OSD、PFL温盐剖面资料,分析了1965-2012年间南海18°N跨海盆断面中层水的变化特征。研究结果表明:中层水平均盐度呈现显著的年代际变化,20世纪60年代中期至70年代末,中层水平均盐度约为34.432,80年代盐度增加至34.440,90年代之后至今盐度明显降低;在年代际尺度变异调制下,不同年代中层水盐度变化有不同的变化趋势,1967-1977年呈现显著的下降趋势,1990-1997年中层水盐度从34.450迅速降为34.414,而在1997年之后表现出明显上升趋势,与此同时,中层水温度有着相似的变化特征,与90年代之前相比,21世纪以来温度与盐度同步下降,并且变化幅度变小。与大洋的中层水团年代际变异相比,南海18°N断面中层水呈现出与大洋不同的特征。另外,中层水盐度有着十分显著的年际变化,其振幅远大于年代际尺度变异,并且与ENSO密切相关,在厄尔尼诺年达到极小值。  相似文献   

1982—1999年珠江流域归一化植被指数与降水年际变化分析     

王银霞  施平  曾丽丽  谢强  王东晓 《热带海洋学报》2011,(4)

利用1982—1999年月平均归一化植被指数(normalized difference vegetation index,NDVI)和降水资料,采用经验正交函数(EOF)方法分别研究了珠江流域的NDVI和降水在年和年际尺度上的异常关系,并分析了NDVI与降水及其他一些气象因子的相关关系。研究发现流域NDVI和降水在年内异常上具有较好的空间一致性,在时间上具有1—2个月的滞后;年际尺度上两者异常空间差异明显,流域东部(下游)异常为负相关,西部(上游)异常为正相关。NDVI和各气候因子的相关关系存在明显的空间和季节差异:流域东部NDVI和降水负相关明显,和温度及太阳短波辐射正相关明显;流域西部NDVI和降水滞后正相关明显,和温度相关不明显;NDVI在夏季和降水呈显著负相关,在春、秋季节滞后于降水,呈明显正相关,且滞后3个月正相关最为明显。  相似文献   

Numerical simulation of the structure and variation of upwelling off the east coast of Hainan Island using QuikSCAT winds   总被引：3，自引：0，他引：3  

李毅能  彭世球  杨威  王东晓 《中国海洋湖沼学报》2012,30(6):1068-1081

The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by QuikSCAT winds. The model produced good simulations of the summer upwelling and the seasonal and annual variability. Strong upwelling occurs from mid-July to mid-August with a peak east of Hainan Island associated with the southwesterly monsoon in the South China Sea. Sensitivity experiments indicated that when the local wind stress controls the variability of the upwelling, the large-scale circulation significantly enhances the upwelling northeast of Hainan Island by inducing a local upwelling and transporting cold water northeast-ward along the island’s east coast. The joint effects of the local wind stress and large-scale circulation result in stronger upwelling northeast of Hainan Island. This implies that the annual variation of the upwelling northeast of Hainan Island is controlled not only by the local alongshore wind stress but also by the large-scale circulation. This result will help us investigate the decadal variation of the upwelling in this region in the future.  相似文献   

A dipole wind curl pattern induced by Taiwan Island and its effect on upper stratification in the northeastern South China Sea   总被引：1，自引：0，他引：1  

邓奕  施平  周文  杜岩  谢强  庄伟  王东晓 《中国海洋湖沼学报》2012,30(6):944-952

Using hydrographic data sampled during four successive late summer-early autumn cruises in 2004-2007, vertical stratification along transects in the lee of Taiwan Island was analyzed to investigate upper ocean responses to orographically induced dipole wind stress curl (WSC). Results indicate that mixed-layer depth (MLD) and its relationship with thermocline depth varied under different local wind forcings. Average MLD along the transects from the 2004 to 2007 cruises were 18.5,30.7,39.2 and 24.5m, respectively. The MLD along the transects deepened remarkably and resulted in thermocline ventilation in 2005 and 2006, whereas ventilation did not occur in 2004 and 2007. Estimates indicate that frictional wind speed was the major factor in MLD variations. To a large degree, the combined effects of frictional wind speed and Ekman pumping are responsible for the spatial pattern of MLD during the cruises.  相似文献   

一个考虑潮汐、中尺度涡和地形影响的南海底部环流诊断模型     

肖劲根  谢强  刘长建  陈举  王东晓  陈美榕 《海洋学报》2013,35(5):1-13

本文构造了一个考虑潮汐、中尺度涡和地形影响下的南海底部环流诊断模型。在该模型中,潮汐混合和涡致混合引起的垂直速率用一个类似的改进参数化方案来表示。该模型结果显示在南海深层吕宋海峡"深水瀑布"和斜压影响最大,潮汐作用和中尺度涡影响次之,风场的影响最小。斜压影响的整体效应与其他因素相反。潮汐混合与涡致混合具有明显的地形依赖性。潮汐混合主要集中在南海北部海盆地形较为陡峭的陆坡区和南海中部海山区,而涡致混合主要集中在海盆西边界区以及中部海山区。在不考虑吕宋海峡"深水瀑布"、潮汐和中尺度涡的情况下(对应吕宋海峡关闭),南海底部环流为反气旋式环流。考虑吕宋海峡"深水瀑布"后,南海底层环流为气旋式环流,而潮汐混合和涡致混合起到加强整个气旋式环流强度的作用。此外,该模型还给出了南海底部环流量级大小与地形坡度之间的密切关系,即地形坡度较大的地方,其流速也大。这对于现场观测有着一定的参考意义。最后,本文用尺度分析的方法从理论上分析了该模型的适用性,证实了该模型具有一定的可靠性。  相似文献   

Effects of the East Asian summer monsoon on tropical cyclone genesis over the South China Sea on an interdecadal time scale     

王鑫  周文  李崇银  王东晓 《大气科学进展》2012,29(2):249-262

Tropical cyclone (TC) genesis over the South China Sea (SCS) during 1965-2004 was analyzed.The locations of TC genesis display evident seasonal changes,with the mean position of formation situated nort...  相似文献   

1992-2011年夏季南海西部离岸流区涡流相互作用特征   总被引：2，自引：1，他引：1  

李晗  王强  黄科  刘钦燕  TILAK Priyadarshan  管玉平  王东晓 《海洋与湖沼》2017,48(5):912-925

本文利用南海海洋再分析产品REDOS（Reanalysis Dataset of the South China Sea）和风场资料CCMP（Cross-Calibrated,Multi-Platform）,从能量学角度探讨了1992-2011年夏季（6-9月）越南离岸流区域涡-流相互作用特征,并通过能量收支方程诊断评估了风应力、压力梯度、正压不稳定以及平流的相对贡献。以越南离岸流的强度作为分类标准,对1992-2011年划分为正异常年、负异常年和正常年。结果表明,在正异常年,涡动能EKE（Eddy Kinetic Energy）和涡势能EPE（Eddy available Potential Energy）极大值主要分布在越南离岸流附近;在负异常年,EKE极大值向南北两侧分散,EPE极大值向北延伸;在正常年,EKE和EPE的极值空间分布介于正负异常之间。斜压不稳定是EPE年际变化的主要因素,越南离岸流影响周围海域的速度和密度分布,是斜压不稳定的主要原因。而影响EKE年际变化的因素较为复杂,压力做功是最主要的影响因素,风应力做功和平流做功次之,正压不稳定最小,其中正压不稳定依赖于流速大小和由风应力旋度扰动引起的上层水平流速剪切。  相似文献   

Mesoscale structure of the central South China Sea detected by SCSMEX Buoy and Argo float     

曾丽丽  王东晓  杜岩  施平 《中国海洋湖沼学报》2010,28(5):1102-1111

We addressed the mesoscale structure variation of the central South China Sea (SCS) with the measurements by a long-lived Argo float and a high-resolution ATLAS buoy during 1998–2002. T-S diagram indicates cooling and freshening events in 2000 and 2001 with lower salinity (0.5–0.8) and lower temperature (1–1.7°C). Significant decrease in the net heat flux and increase in the precipitation suggest that the cooling and freshening is due to extra forcing by the atmosphere. Additional to large year-to-year changes, intraseasonal variability is moderate in the research area. The axis of the maximum intraseasonal temperature and salinity signals are mainly located on the thermocline. Typically, amplitude and period of intraseasonal temperature is about 2°C and 40–60 days, and that of salinity is 0.3–0.5 and 35–60 days. Rapidly-changing winds, heat flux, and precipitation are critical in controlling the intraseasonal fluctuations of the mixed layer of the area. Studies on heat and freshwater balance in the mixed-layer further suggest that horizontal advection plays an important role in intraseasonal fluctuation in the upper ocean. In addition, the energetic mesoscale propagation radiated from the east boundary is linked to the intraseasonal variability in winter.  相似文献   

南海北部海洋温、盐调查研究--2004年9月南海北部开放航次移动船载温盐剖面仪观测   总被引：1，自引：0，他引：1  

刘长建  毛华斌  陈荣裕  王东晓 《热带海洋学报》2005,24(1):89-90

在海洋调查研究过程中,对海水温、盐、深的测量是最关键的几个水文要素。目前国内对于该数据的获取大多是采用定点温盐深仪(简称CTD,如海鸟系列、XR系列等)进行测量。该方法是根据研究需要,在某些断面预先设定好需要观测的站点,然后分别对这些站点进行定点测量,通过所得的站点数据对整个断面进行分析。但由于仪器等方面的原因,这些断面上设定的站点非常有限,  相似文献   

2008年8—9月份吕宋海峡西南侧锚定ADCP的斜压海流观测   总被引：1，自引：0，他引：1  

陈飞  杜岩  王东晓  施平  毛华斌  陈荣裕  陈举 《热带海洋学报》2009,28(4):66-71

2008年8月份在吕宋海峡西侧大约4000m深的海域首次布放了两套深水潜标，对上层海洋进行了为期一个月的高频率ADCP海流采样。对数据进行了多重处理，分解得到平均流和逐层潮流，并分析了具有斜压性海流的频率分布。调和分析结果表明，该海域以不规则日周期潮流为主，潮流椭圆随深度旋转。海流的功率谱分析表明，内潮能量在温跃层附近最大，并随深度减小，同时海流有明显的近惯性振荡信号。该观测为了解吕宋海峡深层海洋的潮流、近惯性运动以及海峡水交换提供了第一手的资料。  相似文献