利用地震海洋学方法研究南海东北部东沙海域内孤立波的结构特征
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摘要
主要利用地震海洋学方法研究了南海东北部东沙海域内孤立波的结构特征,内孤立波的类型是第一模态下沉型,最大振幅有85.5 m.内孤立波自最大振幅所处深度向下,其振幅大体呈线性减小趋势,振幅随深度的减小率为0.2左右.海底对内孤立波的波形会产生一些影响,一方面海底可能会"切割"内孤立波底部,使之出现间断,另一方面海底的"摩擦"会导致近海底的内孤立波处会发育有较多次一级尺度的波动.横向上看,由地震剖面所得到的内孤立波视宽度,需经过一定的校正才能获得真实宽度,本文所研究的两个内孤立波视宽度分别是4.52和3.36 km,校正后的宽度为0.5~3 km.另外内孤立波处存在的垂向噪音反映出内孤立波具有很强的垂向剪切力.内孤立波水平波数谱与GM模型谱的对比研究表明,其能量在低波数段比GM谱大两个数量级左右.
We studied nonlinear internal solitary waves in the northeast South China Sea near Dongsha Atoll, mainly using seismic oceanography. The type of internal solitary wave examined was the first mode depression wave, with maximum amplitude 85.5 m. From the depth of this amplitude and below, the amplitude of solitary waves generally decreased linearly, and the rate of decrease with depth was about 0.2. The seafloor can influence the waveforms of these waves. Specifically, the seafloor can "cut" the bottom of solitary waves, making them discontinuous, and the seafloor "friction" can induce many short waves near it. The apparent width of solitary waves directly from seismic sections should be corrected to obtain true width. Apparent widths of two solitary waves studied were 4.52 and 3.36 km; these were about 0.5–3 km after correction. There was vertical noise at solitary wave locations, reflecting strong vertical shear forces there. The contrast between horizontal wavenumber spectra of the solitary waves and GM(Garrett Munk) model spectra indicate that their wave energy was about two orders of magnitude larger than the GM spectra at low wave numbers.
We studied nonlinear internal solitary waves in the northeast South China Sea near Dongsha Atoll, mainly using seismic oceanography. The type of internal solitary wave examined was the first mode depression wave, with maximum amplitude 85.5 m. From the depth of this amplitude and below, the amplitude of solitary waves generally decreased linearly, and the rate of decrease with depth was about 0.2. The seafloor can influence the waveforms of these waves. Specifically, the seafloor can "cut" the bottom of solitary waves, making them discontinuous, and the seafloor "friction" can induce many short waves near it. The apparent width of solitary waves directly from seismic sections should be corrected to obtain true width. Apparent widths of two solitary waves studied were 4.52 and 3.36 km; these were about 0.5–3 km after correction. There was vertical noise at solitary wave locations, reflecting strong vertical shear forces there. The contrast between horizontal wavenumber spectra of the solitary waves and GM(Garrett Munk) model spectra indicate that their wave energy was about two orders of magnitude larger than the GM spectra at low wave numbers.
引文
1 Cai S Q,Xie J S,He J L.An overview of internal solitary waves in the South China Sea.Surv Geophys,2012,33:927–943
2 Zhao Z X,Klemas V,Zheng Q A,et al.Remote sensing evidence for baroclinic tide origin of internal solitary waves in the northeastern South China Sea.Geophys Res Lett,2004,31:L06302,doi:10.1029/2003GL019077
3 Xu Z H,Yin B S,Hou Y J.Response of internal solitary waves to tropical storm Washi in the northwestern South China Sea.Ann Geophys,2011,29:2181–2187
4 Shaw P T,Ko D S,Chao S Y.Internal solitary waves induced by flow over a ridge:With applications to the northern South China Sea.J Geophys Res,2009,114:C02019,doi:10.1029/2008JC005007
5 Yang Y J,Fang Y C,Chang M H,et al.Observations of second baroclinic mode internal solitary waves on the continental slope of the northern South China Sea.J Geophys Res,2009,114:C10003,doi:10.1029/2009JC005318
6 Cai S Q,Long X M,Gan Z J.A numerical study of the generation and propagation of internal solitary waves in the Luzon Strait.Oceanol Acta,2002,25:51–60
7 Warn-Varnas A,Hawkins J,Lamb K G,et al.Solitary wave generation dynamics at Luzon Strait.Ocean Modell,2010,31:9–27
8 Liu A K,Chang Y S,Hsu M K,et al.Evolution of nonlinear internal waves in the East and South China Seas.J Geophys Res,1998,103:7995–8008
9 Du T,Tseng Y H,Yan X H.Impacts of tidal currents and Kuroshio intrusion on the generation of nonlinear internal waves in Luzon Strait.J Geophys Res,2008,113:C08015,doi:10.1029/2007JC004294
10 Li X F,Zhao Z X,Pichel W G.Internal solitary waves in the northwestern South China Sea inferred from satellite images.Geophys Res Lett,2008,35:L13605,doi:10.1029/2008GL034272
11 Liu A K,Su F C,Hsu M K,et al.Generation and evolution of mode-two internal waves in the South China Sea.Cont Shelf Res,2013,59:18–27
12 Xu Z H,Yin B S,Hou Y J,et al.Variability of internal tides and near-inertial waves on the continental slope of the northwestern South China Sea.J Geophys Res,2013,118:197–2112
13 Chao S Y,Ko D S,Lien R C,et al.Assessing the west ridge of Luzon Strait as an internal wave mediator.J Oceanogr,2007,63:897–911
14 Lynch J F,Ramp S R,Chiu C S,et al.Research highlights from the Asian seas international acoustics experiment in the South China Sea.IEEE J Ocean Eng,2004,29:1067–1074
15 Orr M H,Mignerey P C.Nonlinear internal waves in the South China Sea:Observation of the conversion of depression internal waves to elevation internal waves.J Geophys Res,2003,108:3064,doi:10.1029/2001JC001163
16 Chiu C S,Ramp S R,Miller C W,et al.Acoustic intensity fluctuations induced by South China Sea internal tides and solitons.IEEE J Ocean Eng,2004,29:1249–1263
17 Guo C,Vlasenko V,Alpers W,et al.Evidence of short internal waves trailing strong internal solitary waves in the northern South China Sea from synthetic aperture radar observations.Remote Sens Environ,2012,124:542–550
18 Cheng M H,Hsu J R C,Chen C Y,et al.Modelling the propagation of an internal solitary wave across double ridges and a shelf-slope.Environ Fluid Mech,2008,9:321–340
19 Holbrook W S,Páramo P,Pearse S,et al.Thermohaline fine structure in an oceanographic front from seismic reflection profiling.Science,2003,301:821–824
20 Song H B,Dong C Z,Chen L,et al.Reflection seismic methods for studying physical oceanography:Introduction of seismic oceanography(in Chinese).Progr Geophys,2008,23:1156–1164[宋海斌,董崇志,陈林,等.用反射地震方法研究物理海洋——地震海洋学简介.地球物理学进展,2008,23:1156–1164]
21 Ruddick B,Song H B,Dong C Z,et al.Water column seismic images as maps of temperature gradient.Oceanography,2009,22:192–205
22 Dong C Z,Song H B,Hao T Y,et al.Studying of oceanic internal waves spectral in the northeast South China Sea from seimic reflections(in Chinese).Chin J Geophys,2009,52:2050–2055[董崇志,宋海斌,郝天珧,等.南海东北部海洋内波的反射地震研究.地球物理学报,2009,52:2050–2055]
23 Song H B,Pinheiro L M,Wang D X,et al.Seismic images of ocean meso-scale eddies and internal waves(in Chinese).Chin J Geophys,2009,52 :2775–2780[宋海斌,Pinheiro L M,王东晓,等.海洋中尺度涡与内波的地震图像.地球物理学报,2009,52:2775–2780]
24 Song H B,Bai Y,Dong C Z,et al.A preliminary study of application of empirical mode decomposition method in understanding the features of internal waves in the northeast South China Sea(in Chinese).Chin J Geophys,2010,53:393–400[宋海斌,拜阳,董崇志,等.南海东北部内波特征——经验模态分解方法应用初探.地球物理学报,2010,53:393–400]
25 Huang X H,Song H B,Pinheiro L M,et al.Ocean temperature and salinity distributions inverted from combined reflection seimic and XBT data(in Chinese).Chin J Geophys,2011,54:1293–1300[黄兴辉,宋海斌,Pinheiro L M,等.利用反射地震数据和XBT数据联合反演海水的温盐分布.地球物理学报,2011,54:1293–1300]
26 Chen J X,Song H B,Bai Y,et al.The vertical structure and physical properties of Mediterranean eddy(in Chinese).Chin J Geophys,2013,56:943–952[陈江欣,宋海斌,拜阳,等.地中海涡旋的垂向结构与物理性质.地球物理学报,2013,56:943–952]
27 Huang X H,Song H B,Bai Y,et al.Estimation of Geostrophic velocity from seismic images of mesoscale eddy in the South China Sea(in Chinese).Chin J Geophys,2013,56:181–187[黄兴辉,宋海斌,拜阳,等.利用地震海洋学方法估算南海中尺度涡的地转流速.地球物理学报,2013,56:181–187]
28 Cai S Q,Gan Z J,Long X M.Some characteristics and evolution of the internal soliton in the northern South China Sea(in Chinese).Chin Sci Bull,2001,46:1245–1250[蔡树群,甘子钧,龙小敏.南海北部孤立子内波的一些特征和演变.科学通报,2001,46:1245–1250]
2 Zhao Z X,Klemas V,Zheng Q A,et al.Remote sensing evidence for baroclinic tide origin of internal solitary waves in the northeastern South China Sea.Geophys Res Lett,2004,31:L06302,doi:10.1029/2003GL019077
3 Xu Z H,Yin B S,Hou Y J.Response of internal solitary waves to tropical storm Washi in the northwestern South China Sea.Ann Geophys,2011,29:2181–2187
4 Shaw P T,Ko D S,Chao S Y.Internal solitary waves induced by flow over a ridge:With applications to the northern South China Sea.J Geophys Res,2009,114:C02019,doi:10.1029/2008JC005007
5 Yang Y J,Fang Y C,Chang M H,et al.Observations of second baroclinic mode internal solitary waves on the continental slope of the northern South China Sea.J Geophys Res,2009,114:C10003,doi:10.1029/2009JC005318
6 Cai S Q,Long X M,Gan Z J.A numerical study of the generation and propagation of internal solitary waves in the Luzon Strait.Oceanol Acta,2002,25:51–60
7 Warn-Varnas A,Hawkins J,Lamb K G,et al.Solitary wave generation dynamics at Luzon Strait.Ocean Modell,2010,31:9–27
8 Liu A K,Chang Y S,Hsu M K,et al.Evolution of nonlinear internal waves in the East and South China Seas.J Geophys Res,1998,103:7995–8008
9 Du T,Tseng Y H,Yan X H.Impacts of tidal currents and Kuroshio intrusion on the generation of nonlinear internal waves in Luzon Strait.J Geophys Res,2008,113:C08015,doi:10.1029/2007JC004294
10 Li X F,Zhao Z X,Pichel W G.Internal solitary waves in the northwestern South China Sea inferred from satellite images.Geophys Res Lett,2008,35:L13605,doi:10.1029/2008GL034272
11 Liu A K,Su F C,Hsu M K,et al.Generation and evolution of mode-two internal waves in the South China Sea.Cont Shelf Res,2013,59:18–27
12 Xu Z H,Yin B S,Hou Y J,et al.Variability of internal tides and near-inertial waves on the continental slope of the northwestern South China Sea.J Geophys Res,2013,118:197–2112
13 Chao S Y,Ko D S,Lien R C,et al.Assessing the west ridge of Luzon Strait as an internal wave mediator.J Oceanogr,2007,63:897–911
14 Lynch J F,Ramp S R,Chiu C S,et al.Research highlights from the Asian seas international acoustics experiment in the South China Sea.IEEE J Ocean Eng,2004,29:1067–1074
15 Orr M H,Mignerey P C.Nonlinear internal waves in the South China Sea:Observation of the conversion of depression internal waves to elevation internal waves.J Geophys Res,2003,108:3064,doi:10.1029/2001JC001163
16 Chiu C S,Ramp S R,Miller C W,et al.Acoustic intensity fluctuations induced by South China Sea internal tides and solitons.IEEE J Ocean Eng,2004,29:1249–1263
17 Guo C,Vlasenko V,Alpers W,et al.Evidence of short internal waves trailing strong internal solitary waves in the northern South China Sea from synthetic aperture radar observations.Remote Sens Environ,2012,124:542–550
18 Cheng M H,Hsu J R C,Chen C Y,et al.Modelling the propagation of an internal solitary wave across double ridges and a shelf-slope.Environ Fluid Mech,2008,9:321–340
19 Holbrook W S,Páramo P,Pearse S,et al.Thermohaline fine structure in an oceanographic front from seismic reflection profiling.Science,2003,301:821–824
20 Song H B,Dong C Z,Chen L,et al.Reflection seismic methods for studying physical oceanography:Introduction of seismic oceanography(in Chinese).Progr Geophys,2008,23:1156–1164[宋海斌,董崇志,陈林,等.用反射地震方法研究物理海洋——地震海洋学简介.地球物理学进展,2008,23:1156–1164]
21 Ruddick B,Song H B,Dong C Z,et al.Water column seismic images as maps of temperature gradient.Oceanography,2009,22:192–205
22 Dong C Z,Song H B,Hao T Y,et al.Studying of oceanic internal waves spectral in the northeast South China Sea from seimic reflections(in Chinese).Chin J Geophys,2009,52:2050–2055[董崇志,宋海斌,郝天珧,等.南海东北部海洋内波的反射地震研究.地球物理学报,2009,52:2050–2055]
23 Song H B,Pinheiro L M,Wang D X,et al.Seismic images of ocean meso-scale eddies and internal waves(in Chinese).Chin J Geophys,2009,52 :2775–2780[宋海斌,Pinheiro L M,王东晓,等.海洋中尺度涡与内波的地震图像.地球物理学报,2009,52:2775–2780]
24 Song H B,Bai Y,Dong C Z,et al.A preliminary study of application of empirical mode decomposition method in understanding the features of internal waves in the northeast South China Sea(in Chinese).Chin J Geophys,2010,53:393–400[宋海斌,拜阳,董崇志,等.南海东北部内波特征——经验模态分解方法应用初探.地球物理学报,2010,53:393–400]
25 Huang X H,Song H B,Pinheiro L M,et al.Ocean temperature and salinity distributions inverted from combined reflection seimic and XBT data(in Chinese).Chin J Geophys,2011,54:1293–1300[黄兴辉,宋海斌,Pinheiro L M,等.利用反射地震数据和XBT数据联合反演海水的温盐分布.地球物理学报,2011,54:1293–1300]
26 Chen J X,Song H B,Bai Y,et al.The vertical structure and physical properties of Mediterranean eddy(in Chinese).Chin J Geophys,2013,56:943–952[陈江欣,宋海斌,拜阳,等.地中海涡旋的垂向结构与物理性质.地球物理学报,2013,56:943–952]
27 Huang X H,Song H B,Bai Y,et al.Estimation of Geostrophic velocity from seismic images of mesoscale eddy in the South China Sea(in Chinese).Chin J Geophys,2013,56:181–187[黄兴辉,宋海斌,拜阳,等.利用地震海洋学方法估算南海中尺度涡的地转流速.地球物理学报,2013,56:181–187]
28 Cai S Q,Gan Z J,Long X M.Some characteristics and evolution of the internal soliton in the northern South China Sea(in Chinese).Chin Sci Bull,2001,46:1245–1250[蔡树群,甘子钧,龙小敏.南海北部孤立子内波的一些特征和演变.科学通报,2001,46:1245–1250]
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