引用本文: 孙绍箐, 张锟, 宋海斌. 2019. 地中海直布罗陀海峡附近内孤立波的地球物理特征. 地球物理学报, 62(7): 2622-2632, doi: 10.6038/cjg2019N0079

本文主要利用地震海洋学方法研究地中海直布罗陀海峡附近内孤立波的结构特征，此处内孤立波为第一模态下沉型，为中幅度和大幅度内孤立波，垂向振幅最大可达74.5 m，振幅随深度增加呈增大趋势，传播速度随振幅增大而增大，可以确定"真"最大振幅位置位于密跃层附近.由于类多普勒效应和孤立波与测量船之间存在夹角的原因，从地震剖面上得到的为视半高宽参数，需要进行校正后才能得到比较真实的半高宽参数，校正后半高宽最高可达到1721.8 m，但是校正后的半高宽与理论结果有些差距，这可能与内孤立波的发育稳定程度有关.随着内孤立波包不断向东运动，整体波宽变大，垂向速度变小.本文将地震海洋学方法拓展应用于地中海区域内孤立波分析，进一步证明了利用地震海洋学方法研究海水运动的可行性.

地震海洋学 Abstract:

This work used the seismic oceanography method to study the structural characteristics of internal solitary waves (ISWs) near the Strait of Gibraltar in the Mediterranean Sea. The ISWs are the first mode decline type, mostly with medium and large amplitudes. The maximum vertical amplitude is up to 74.5 m. The amplitude increases with depth, and its propagation velocity increases with amplitude. It can be determined that the "true" maximum amplitude position is near the pycnocline. Because of the Doppler-like effect and the angle between the ISWs and the ship, we need to correct the half-height-width parameter obtained from the seismic section to get the true half-height-width parameter. After correction, the maximum half-height-width can reach 1721.8 m, but there is somewhat different from the theoretical result, which may be related to the development stability of ISWs. As the solitary wave packet continuously moves eastward, the overall wave width becomes larger, and the vertical velocity becomes smaller. In this work, seismic oceanography was applied to the analysis of ISWs in the Mediterranean Sea, which further proves the feasibility of using seismic oceanography to study movement of sea water.

Key words: Seismic oceanography Internal solitary wave Mediterranean Sea Structural characteristics Tang Q S, Wang C X, Wang D X, et al. 2014. Seismic, satellite, and site observations of internal solitary waves in the NE South China Sea. Scientific Reports, 4:5374. https://www.ncbi.nlm.nih.gov/pubmed/24948180 陈江欣, 拜阳, 关永贤等. 2016.海底边界层异常(地震海洋学)反射地震特征的地球物理分析.地球物理学报, 59(6):2148-2161, doi: 10.6038/cjg20160620 . http://www.geophy.cn//CN/abstract/abstract12859.shtml 耿明会, 宋海斌, 关永贤等. 2018.南海北部雾状层分布和特征的地震海洋学研究.地球物理学报, 61(2):636-648, doi: 10.6038/cjg2018L0662 . http://www.geophy.cn//CN/abstract/abstract14362.shtml 黄晞桐, 宋海斌, 关永贤等. 2018.基于流体动力学数值模拟的海水层反射地震研究.地球物理学报, 61(7):2892-2904, doi: 10.6038/cjg2018L0382 . http://www.geophy.cn//CN/abstract/abstract14597.shtml 宋海斌, 陈江欣, 赵庆献等. 2018.南海东北部地震海洋学联合调查与反演.地球物理学报, 61(9):3760-3769, doi: 10.6038/cjg2018L0446 . http://www.geophy.cn//CN/abstract/abstract14677.shtml Figure 1.

Global distribution of internal isolation waves (modified after Global Ocean Associates(2002) )

Figure 2.

Distribution of multi-channel seismic data (the black curve represents the original seismic line, and the red part represents the part with internal solitary waves, the position of Fig. 3 and Fig. 4 )

Figure 3.

Internal solitary wave packet on line 1 (the arrow indicates the propagation direction of internal solitary waves)

Figure 4.

Internal isolated wave packet on line 2 (the arrow indicates the propagation direction of internal solitary waves)

Figure 5.

Amplitude variation of isolated waves in line 1

Figure 6.

Amplitude variation of isolated waves in line 2

Figure 7.

Diagram of relative motion of the ship and solitary wave

Figure 8.

Schematic diagram of internal solitary wave structure (modified after Tang et al.(2015) )

Figure 9.

Vertical variation of amplitudes of 8 internal solitary waves in line 2

Figure 10.

The Brunt-Vaisala frequency profile (calculated with the salt-temperature data closest to the seismic line, H _p is the pycnocline depth, d H _p is the pycnocline width, N _m is the maximal value of the buoyancy frequency, 0.5 N _m is half of the maximum buoyancy frequency)