基于潜标资料的中南半岛外海水文特征分析
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摘要
基于2012年9月—2013年12月中南半岛外海累计16个月的长时间序列潜标观测数据,结合AVISO海表面高度异常(sea level anomaly,SLA)数据,首次详细分析了中南半岛外海典型中尺度涡的运动规律和垂向特征及其对环境水文特征的影响,揭示了该海域深层海流的时间变化特征。在观测期间共捕捉到3次中尺度涡过程,中尺度涡对站位所在海域主温跃层深度变化的最大影响振幅可达50 m。研究发现:1)观测站位所在海域各深度的温度异常时间变化与站位SLA时间变化的相关性随深度增加逐渐减弱。2)上层和中层的海水流动受中尺度涡影响显著。1 500 m和2 000 m的深层环流主要表现为季节变化;在强中尺度涡暖涡经过期间,中尺度涡能影响到1 500 m的环流场,同时出现30 d周期震荡。2 000 m流场则不受中尺度涡影响。3)中南半岛以东南海1 500 m处深层海流月平均流速夏季大于冬季,月平均可达3.5 cm·s~(-1);2 000 m处深层海流最大流速出现在冬季,月平均可达2.6 cm·s~(-1)。深层海流受潮汐影响显著,潮汐作用主要影响深层海流东西向流速的变化。
Using the 16 months' mooring data measured from September 2012 to December 2013 and the AVISO sea level anomaly data( SLA),we study the hydrological characteristics of mesoscale eddy and the deepwater circulation variations east of Indochina Peninsula. During the observation period,three mesoscale eddies are captured. Maximum amplitude of thermocline depth displacements,which are induced by local mesoscale eddies,on the mooring site can reach up to 50 m. The main conclusions are as follows. 1) In the mooring region,the time series correlation between temperature anomaly and the SLA weakens with the depth. 2) In the mooring region, mesoscale eddies affect the upper andintermediate hydrological conditions significantly. Deepwater circulation at 1 500 m and 2 000 m is primarily characterized by seasonal variations. Strong warm mesoscale eddies can influence deepwater circulation at 1 500 m depth,in the meanwhile,the deepwater velocity has strong 30-day periodical oscillations. However,the deepwater circulation at 2 000 m is not influenced by mesoscale eddies. 3) In the mooring region,the monthly mean velocity of deepwater circulation at 1 500 m in summer is larger than that in winter,the monthly mean velocity is up to 3. 5 cm · s~(-1). Strong velocity of the deepwater circulation at 2 000 m depth appears in winter,the monthly mean velocity is up to 2. 6 cm·s~(-1). The tide significantly influences the deepwater circulation,and the influences can reach 2 000 m depth and mainly on zonal direction.
Using the 16 months' mooring data measured from September 2012 to December 2013 and the AVISO sea level anomaly data( SLA),we study the hydrological characteristics of mesoscale eddy and the deepwater circulation variations east of Indochina Peninsula. During the observation period,three mesoscale eddies are captured. Maximum amplitude of thermocline depth displacements,which are induced by local mesoscale eddies,on the mooring site can reach up to 50 m. The main conclusions are as follows. 1) In the mooring region,the time series correlation between temperature anomaly and the SLA weakens with the depth. 2) In the mooring region, mesoscale eddies affect the upper andintermediate hydrological conditions significantly. Deepwater circulation at 1 500 m and 2 000 m is primarily characterized by seasonal variations. Strong warm mesoscale eddies can influence deepwater circulation at 1 500 m depth,in the meanwhile,the deepwater velocity has strong 30-day periodical oscillations. However,the deepwater circulation at 2 000 m is not influenced by mesoscale eddies. 3) In the mooring region,the monthly mean velocity of deepwater circulation at 1 500 m in summer is larger than that in winter,the monthly mean velocity is up to 3. 5 cm · s~(-1). Strong velocity of the deepwater circulation at 2 000 m depth appears in winter,the monthly mean velocity is up to 2. 6 cm·s~(-1). The tide significantly influences the deepwater circulation,and the influences can reach 2 000 m depth and mainly on zonal direction.
引文
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[3]Hwang C,Chen S A.Circulations and eddies over the South China Sea derived from TOPEX/Poseidon altimetry[J].Journal of Geophysical Research:Oceans(1978-2012),2000,105(C10):23943-23965.
[4]Wang G H,Chen D,Su J.Winter eddy genesis in the eastern South China Sea due to orographic wind jets[J].Journal of Physical Oceanography,2008,38(3):726.
[5]Tian J W,Qu T D.Advances in research on the deep South China Sea circulation[J].Chinese Science Bulletin,2012,57(24):3115-3120.
[6]钟超,肖武鹏,黄邦钦.中国南海西部浮游植物对中尺度涡的响应[J].海洋科学进展,2013,31(2):213-220.DOI:10.3969/j.issn.1671-6647.2013.02.007.
[7]Zhang Z W,Zhao W,Tian J,et al.A mesoscale eddy pair southwest of Taiwan and its influence on deep circulation[J].Journal of Geophysical Research Oceans,2013,118(12):6479-6494.
[8]王斌.吕宋海峡及南海深层环流的观测与数值模拟研究及机制分析[D].青岛:中国海洋大学,2012.
[9]Wang G H,Xie S,Qu T,et al.Deep South China Sea circulation[J].Geophysical Research Letters,2011,38(5):3115-3120.
[10]Zhou C,Zhao W,Tian J,et al.Variability of the deep water overflow in the Luzon Strait[J].Journal of Physical Oceanography,2014,44:2972-2986.
[11]Chu P C,Fan C,Lozano C J,et al.An airborne expendable bathythermograph survey of the South China Sea,May 1995[J].Journal of Geophysical Research:Oceans(1978-2012),1998,103(C10):21637-21652.
[12]阎俊岳.南海西南季风爆发的气候特征[J].气象学报,1997,55(2):174-186.
[13]Chu P C,Lu S,Chen Y.Temporal and spatial variabilities of the South China Sea surface temperature anomaly[J].Journal of Geophysical Research:Oceans(1978-2012),1997,102(C9):20937-20955.
[14]朱晓婷,陈学恩.南海西部海流和温度长期定点观测分析[J].中国海洋大学学报(自然科学版),2014,44(4):15-21.
[15]展鹏,陈学恩,胡学军,等.夏季长江口外东海海域实测海流资料分析[J].中国海洋大学学报(自然科学版),2010,40(8):34-42.DOI:10.3969/j.issn.1672-5174.2010.08.005.
[16]Chao S Y,Shaw P T,Wu S Y.Deep water ventilation in the South China Sea[J].Deep Sea Research Part I:Oceanographic Research Papers,1996,43(4):445-466.