利用高分辨率水体反射地震资料研究吕宋海峡以东黑潮区混合
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摘要
混合过程是海洋中普遍存在的一种形式,对气候变化、物质分布等起到了重要作用。地震海洋学是近十多年发展起来的一门新兴学科,被广泛应用到物理海洋学问题的研究中,具有高空间分辨率的突出优点。文章利用反射地震资料,通过斜率谱方法,分别获得了吕宋海峡以东黑潮区湍流段与内波段的耗散率及扩散率。结果显示,在剖面深度200～800m的平均耗散率为10–7.0W·kg~(–1),平均扩散率为10–3.3m~2·s~(–1),比大洋统计均值10–5.0m~2·s~(–1)高约1～2个量级,与前人在吕宋海峡的观测结果相一致。湍流段和内波段的扩散率空间分布差异较大:湍流段扩散率高值区对应强流区域,推测这里是中尺度涡边缘,其次中尺度不稳定过程引起扰动增强,进而引起湍流混合的加强;内波段扩散率高值区出现在吕宋岛弧附近,推测是内波遇到岛弧地形发生破碎,进而引起强的内波混合。
Mixing is a ubiquitous motion in the ocean, which plays an important role in climate change and matter distribution.Seismic Oceanography is a new discipline in recent 10 years; it has been widely applied to Physical Oceanography, because it has the advantage of high spatial resolution. Seismic reflection data were used in this study, along with slope spectral method.We obtained the dissipation rate and diffusivity of turbulence interval and internal wave interval respectively in the Kuroshio(located in the east of the Luzon Strait). The results show that the average dissipation rate from 200-to 800-m depth in this profile is 10-7.0 W·kg-1, and the average diffusivity is 10-3.3 m2·s-1, which is about 1-2 order of magnitude higher than the average value in the ocean 10-5.0 m2·s-1. This result is consistent with previous mixing observations in the Luzon Strait. There is a big difference in diffusivity spatial distribution between turbulence interval and internal wave interval: the region where strong current occurs is consistent with that of high turbulence diffusivity in the profile, from which we can infer that this place may be the periphery of mesoscale eddy; its sub-mesoscale instability can strengthen the destabilization and then lead to strong mixing. The high internal wave diffusivity appears near the Luzon Arc, which indicates that the internal wave breaking occurs when it meets the island arc, leading to strong internal wave mixing.
Mixing is a ubiquitous motion in the ocean, which plays an important role in climate change and matter distribution.Seismic Oceanography is a new discipline in recent 10 years; it has been widely applied to Physical Oceanography, because it has the advantage of high spatial resolution. Seismic reflection data were used in this study, along with slope spectral method.We obtained the dissipation rate and diffusivity of turbulence interval and internal wave interval respectively in the Kuroshio(located in the east of the Luzon Strait). The results show that the average dissipation rate from 200-to 800-m depth in this profile is 10-7.0 W·kg-1, and the average diffusivity is 10-3.3 m2·s-1, which is about 1-2 order of magnitude higher than the average value in the ocean 10-5.0 m2·s-1. This result is consistent with previous mixing observations in the Luzon Strait. There is a big difference in diffusivity spatial distribution between turbulence interval and internal wave interval: the region where strong current occurs is consistent with that of high turbulence diffusivity in the profile, from which we can infer that this place may be the periphery of mesoscale eddy; its sub-mesoscale instability can strengthen the destabilization and then lead to strong mixing. The high internal wave diffusivity appears near the Luzon Arc, which indicates that the internal wave breaking occurs when it meets the island arc, leading to strong internal wave mixing.
引文
拜阳,宋海斌,董崇志,等,2015.地震海洋学方法在海洋混合参数提取中的研究与应用--以南海内波和地中海涡旋为例[J].地球物理学报,58(7):2473-2485.BAI YANG,SONGHAIBIN,DONG CHONGZHI,et al,2015.Extraction ofmixing parameters by seismic oceanography and applications:Case study of the internal waves in South China Sea and Mediterranean eddy[J].Chinese Journal of Geophysics,58(7):2473-2485(in Chinese with English abstract).
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冯士筰,李凤岐,李少菁,1999.海洋科学导论[M].北京:高等教育出版社.FENG SHIZUO,LI FENGQI,LI SHAOJING.An introduction to marine science[M].Beijing:Higher Education Press(in Chinese).
宋海斌,董崇志,陈林,等,2008.用反射地震方法研究物理海洋-地震海洋学简介[J].地球物理学进展,23(4):1156-1164.SONG HAIBIN,DONG CHONGZHI,CHENLIN,et al,2008.Reflection seismic methods for studying physical oceanography:Introduction of seismic oceanography[J].Progress in Geophysics,23(4):1156-1164(in Chinese with English abstract).
郑瑞玺,经志友,罗士浩,2018.南海北部反气旋涡旋边缘的次中尺度动力过程分析[J].热带海洋学报,37(3):19-25.ZHENG RUIXI,JING ZHIYOU,LUO SHIHAO,2018.Analysis of sub-mesoscale dynamic processes in the periphery of anticyclonic eddy in the northern South China Sea[J].Journal of Tropical Oceanography,37(3):19-25(in Chinese with English abstract).
BATCHELOR G K,1959.Small-scale variation of convected quantities like temperature in turbulent fluid Part 1.General discussion and the case of small conductivity[J].Journal of Fluid Mechanics,5(1):113-133.
CARUSO M J,GAWARKIEWICZ G G,BEARDSLEY R C,2006.Interannual variability of the Kuroshio intrusion in the South China Sea[J].Journal of Oceanography,62(4):559-575.
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FALDER M,WHITE N J,CAULFIELD C P,2016.Seismic imaging of rapid onset of stratified turbulence in the south Atlantic Ocean[J].Journal of Physical Oceanography,46(4):1023-1044.
GARRETT C,MUNK W,1975.Space-time scales of internal waves:a progress report[J].Journal of Geophysical Research,80(3):291-297.
GREGG M C,1989.Scaling turbulent dissipation in the thermocline[J].Journal of Geophysical Research:Oceans,94(C7):9686-9698.
HENYEY F S,WRIGHT J,FLATTéS M,1986.Energy and action flow through the internal wave field:an eikonal approach[J].Journal of Geophysical Research:Oceans,91(C7):8487-8495.
HOLBROOK W S,PáRAMO P,PEARSE S,et al,2003.Thermohaline fine structure in an oceanographic front from seismic reflection profiling[J].Science,301(5634):821-824.
HOLBROOK W S,FER I,SCHMITT R W,2009.Images of internal tides near the Norwegian continental slope[J].Geophysical Research Letters,36(24):L00D10.
HOLBROOK W S,FER I,SCHMITT R W,et al,2013.Estimating oceanic turbulence dissipation from seismic images[J].Journal of Atmospheric and Oceanic Technology,30(8):1767-1788.
HU JIANYU,KAWAMURA H,HONG HUASHENG,et al,2000.A review on the currents in the South China Sea:seasonal circulation,South China Sea warm current and Kuroshio intrusion[J].Journal of Oceanography,56(6):607-624.
KLYMAK J M,MOUM J N,2007a.Oceanic isopycnal slope spectra.Part I:internal waves[J].Journal of Physical Oceanography,37(5):1215-1231.
KLYMAK J M,MOUM J N,2007b.Oceanic isopycnal slope spectra.Part II:turbulence[J].Journal of Physical Oceanography,37(5):1232-1245.
MACKINNON J,ST LAURENT L,GARABATO A C N,2013.Diapycnal mixing processes in the ocean interior[J].International Geophysics,103:159-183.
MAO H,SUN Z,LI X,2016.Observations of water mass mixing in the Luzon strait[C]//Proceedings of the American Geophysical Union,Ocean Sciences Meeting,2016,abstract#A34B-2648.
MüLLER P,BRISCOE M,2000.Diapycnal mixing and internal waves[J].Oceanography,13(2):98-103.
NAN F,XUE H J,CHAI F,et al,2011.Identification of different types of Kuroshio intrusion into the South China Sea[J].Ocean Dynamics,61(9):1291-1304.
NAN FENG,XUE HUIJIE,YU FEI,2015.Kuroshio intrusion into the South China Sea:a review[J].Progress in Oceanography,137:314-333.
OSBORN T R,1980.Estimates of the local rate of vertical diffusion from dissipation measurements[J].Journal of Physical Oceanography,10(1):83-89.
PINKEL R,BUIJSMAN M,KLYMAK J M,2012.Breaking topographic lee waves in a tidal channel in Luzon Strait[J].Oceanography,25(2):160-165.
RAHMSTORF S,2003.Thermohaline circulation:the current climate[J].Nature,421(6924):699.
SALLARES V,MOJICA J F,BIESCAS B,et al,2016.Characterization of the submesoscale energy cascade in the Alboran Sea thermocline from spectral analysis of highresolution MCS data[J].Geophysical Research Letters,43(12):6461-6468.
SHAW P T,CHAO S Y,1994.Surface circulation in the South China sea[J].Deep Sea Research Part I:Oceanographic Research Papers,41(11-12):1663-1683.
SHEEN K L,WHITE N J,HOBBS R W,2009.Estimating mixing rates from seismic images of oceanic structure[J].Geophysical Research Letters,36(24):L00D04.
SHEU D D,CHOU W C,CHEN C T A,et al,2009.Riding over the Kuroshio from the South to the East China Sea:mixing and transport of DIC[J].Geophysical Research Letters,36(7):L07603.
SIMMONS H,CHANG M H,CHANG Y T,et al,2011.Modeling and prediction of internal waves in the South China Sea[J].Oceanography,24(4):88-99.
SREENIVASAN K R,1996.The passive scalar spectrum and the Obukhov-Corrsin constant[J].Physics of Fluids,8(1):189-196.
STEWART R H,2008.Introduction to physical oceanography[M].Texas:Texas A&M University.
TANG QUNSHU,ZHENG CHAN,2011.Thermohaline structures across the Luzon Strait from seismic reflection data[J].Dynamics of Atmospheres and Oceans,51(3):94-108.
THOMAS L N,TAYLOR J R,FERRARI R,et al,2013.Symmetric instability in the gulf stream[J].Deep Sea Research Part II:Topical Studies in Oceanography,91:96-110.
THORPE S A,2010.Breaking internal waves and turbulent dissipation[J].Journal of Marine Research,68(6):851-880.
TIAN JIWEI,YANG QINGXUAN,LIANG XINFENG,et al,2006.Observation of Luzon Strait transport[J].Geophysical Research Letters,33(19):L19607.
TIAN JIWEI,YANG QINGXUAN,ZHAO WEI,2009.Enhanced Diapycnal mixing in the South China Sea[J].Journal of Physical Oceanography,39(12):3191-3203.
VAN HAREN H,GOSTIAUX L,2012.Energy release through internal wave breaking[J].Oceanography,25(2):124-131.
YANG QINGXUAN,ZHOU LEI,TIAN JIWEI,et al,2014.The roles of Kuroshio intrusion and mesoscale eddy in upper mixing in the northern South China Sea[J].Journal of Coastal Research,30(1):192-198.
YANG QINGXUAN,ZHAO WEI,LIANG XINFENG,et al,2017.Elevated mixing in the periphery of mesoscale eddies in the South China Sea[J].Journal of Physical Oceanography,47(4):895-907.
ZHAO ZHONGXIANG,2014.Internal tide radiation from the Luzon Strait[J].Journal of Geophysical Research:Oceans,119(8):5434-5448.
范植松,2002.海洋内部混合研究基础[M].北京:海洋出版社.FAN ZHISONG.Research fundamentals of ocean interior mixing[M].Beijing:China Ocean Press(in Chinese).
冯士筰,李凤岐,李少菁,1999.海洋科学导论[M].北京:高等教育出版社.FENG SHIZUO,LI FENGQI,LI SHAOJING.An introduction to marine science[M].Beijing:Higher Education Press(in Chinese).
宋海斌,董崇志,陈林,等,2008.用反射地震方法研究物理海洋-地震海洋学简介[J].地球物理学进展,23(4):1156-1164.SONG HAIBIN,DONG CHONGZHI,CHENLIN,et al,2008.Reflection seismic methods for studying physical oceanography:Introduction of seismic oceanography[J].Progress in Geophysics,23(4):1156-1164(in Chinese with English abstract).
郑瑞玺,经志友,罗士浩,2018.南海北部反气旋涡旋边缘的次中尺度动力过程分析[J].热带海洋学报,37(3):19-25.ZHENG RUIXI,JING ZHIYOU,LUO SHIHAO,2018.Analysis of sub-mesoscale dynamic processes in the periphery of anticyclonic eddy in the northern South China Sea[J].Journal of Tropical Oceanography,37(3):19-25(in Chinese with English abstract).
BATCHELOR G K,1959.Small-scale variation of convected quantities like temperature in turbulent fluid Part 1.General discussion and the case of small conductivity[J].Journal of Fluid Mechanics,5(1):113-133.
CARUSO M J,GAWARKIEWICZ G G,BEARDSLEY R C,2006.Interannual variability of the Kuroshio intrusion in the South China Sea[J].Journal of Oceanography,62(4):559-575.
D'ASARO E,LEE C,RAINVILLE L,et al,2011.Enhanced turbulence and energy dissipation at ocean fronts[J].Science,332(6027):318-322.
FALDER M,WHITE N J,CAULFIELD C P,2016.Seismic imaging of rapid onset of stratified turbulence in the south Atlantic Ocean[J].Journal of Physical Oceanography,46(4):1023-1044.
GARRETT C,MUNK W,1975.Space-time scales of internal waves:a progress report[J].Journal of Geophysical Research,80(3):291-297.
GREGG M C,1989.Scaling turbulent dissipation in the thermocline[J].Journal of Geophysical Research:Oceans,94(C7):9686-9698.
HENYEY F S,WRIGHT J,FLATTéS M,1986.Energy and action flow through the internal wave field:an eikonal approach[J].Journal of Geophysical Research:Oceans,91(C7):8487-8495.
HOLBROOK W S,PáRAMO P,PEARSE S,et al,2003.Thermohaline fine structure in an oceanographic front from seismic reflection profiling[J].Science,301(5634):821-824.
HOLBROOK W S,FER I,SCHMITT R W,2009.Images of internal tides near the Norwegian continental slope[J].Geophysical Research Letters,36(24):L00D10.
HOLBROOK W S,FER I,SCHMITT R W,et al,2013.Estimating oceanic turbulence dissipation from seismic images[J].Journal of Atmospheric and Oceanic Technology,30(8):1767-1788.
HU JIANYU,KAWAMURA H,HONG HUASHENG,et al,2000.A review on the currents in the South China Sea:seasonal circulation,South China Sea warm current and Kuroshio intrusion[J].Journal of Oceanography,56(6):607-624.
KLYMAK J M,MOUM J N,2007a.Oceanic isopycnal slope spectra.Part I:internal waves[J].Journal of Physical Oceanography,37(5):1215-1231.
KLYMAK J M,MOUM J N,2007b.Oceanic isopycnal slope spectra.Part II:turbulence[J].Journal of Physical Oceanography,37(5):1232-1245.
MACKINNON J,ST LAURENT L,GARABATO A C N,2013.Diapycnal mixing processes in the ocean interior[J].International Geophysics,103:159-183.
MAO H,SUN Z,LI X,2016.Observations of water mass mixing in the Luzon strait[C]//Proceedings of the American Geophysical Union,Ocean Sciences Meeting,2016,abstract#A34B-2648.
MüLLER P,BRISCOE M,2000.Diapycnal mixing and internal waves[J].Oceanography,13(2):98-103.
NAN F,XUE H J,CHAI F,et al,2011.Identification of different types of Kuroshio intrusion into the South China Sea[J].Ocean Dynamics,61(9):1291-1304.
NAN FENG,XUE HUIJIE,YU FEI,2015.Kuroshio intrusion into the South China Sea:a review[J].Progress in Oceanography,137:314-333.
OSBORN T R,1980.Estimates of the local rate of vertical diffusion from dissipation measurements[J].Journal of Physical Oceanography,10(1):83-89.
PINKEL R,BUIJSMAN M,KLYMAK J M,2012.Breaking topographic lee waves in a tidal channel in Luzon Strait[J].Oceanography,25(2):160-165.
RAHMSTORF S,2003.Thermohaline circulation:the current climate[J].Nature,421(6924):699.
SALLARES V,MOJICA J F,BIESCAS B,et al,2016.Characterization of the submesoscale energy cascade in the Alboran Sea thermocline from spectral analysis of highresolution MCS data[J].Geophysical Research Letters,43(12):6461-6468.
SHAW P T,CHAO S Y,1994.Surface circulation in the South China sea[J].Deep Sea Research Part I:Oceanographic Research Papers,41(11-12):1663-1683.
SHEEN K L,WHITE N J,HOBBS R W,2009.Estimating mixing rates from seismic images of oceanic structure[J].Geophysical Research Letters,36(24):L00D04.
SHEU D D,CHOU W C,CHEN C T A,et al,2009.Riding over the Kuroshio from the South to the East China Sea:mixing and transport of DIC[J].Geophysical Research Letters,36(7):L07603.
SIMMONS H,CHANG M H,CHANG Y T,et al,2011.Modeling and prediction of internal waves in the South China Sea[J].Oceanography,24(4):88-99.
SREENIVASAN K R,1996.The passive scalar spectrum and the Obukhov-Corrsin constant[J].Physics of Fluids,8(1):189-196.
STEWART R H,2008.Introduction to physical oceanography[M].Texas:Texas A&M University.
TANG QUNSHU,ZHENG CHAN,2011.Thermohaline structures across the Luzon Strait from seismic reflection data[J].Dynamics of Atmospheres and Oceans,51(3):94-108.
THOMAS L N,TAYLOR J R,FERRARI R,et al,2013.Symmetric instability in the gulf stream[J].Deep Sea Research Part II:Topical Studies in Oceanography,91:96-110.
THORPE S A,2010.Breaking internal waves and turbulent dissipation[J].Journal of Marine Research,68(6):851-880.
TIAN JIWEI,YANG QINGXUAN,LIANG XINFENG,et al,2006.Observation of Luzon Strait transport[J].Geophysical Research Letters,33(19):L19607.
TIAN JIWEI,YANG QINGXUAN,ZHAO WEI,2009.Enhanced Diapycnal mixing in the South China Sea[J].Journal of Physical Oceanography,39(12):3191-3203.
VAN HAREN H,GOSTIAUX L,2012.Energy release through internal wave breaking[J].Oceanography,25(2):124-131.
YANG QINGXUAN,ZHOU LEI,TIAN JIWEI,et al,2014.The roles of Kuroshio intrusion and mesoscale eddy in upper mixing in the northern South China Sea[J].Journal of Coastal Research,30(1):192-198.
YANG QINGXUAN,ZHAO WEI,LIANG XINFENG,et al,2017.Elevated mixing in the periphery of mesoscale eddies in the South China Sea[J].Journal of Physical Oceanography,47(4):895-907.
ZHAO ZHONGXIANG,2014.Internal tide radiation from the Luzon Strait[J].Journal of Geophysical Research:Oceans,119(8):5434-5448.