Journal of Tropical Oceanography >
Study on the characteristics of internal solitary waves in the Dongsha area of the northern South China Sea based on acoustic backscatter data*
Copy editor: LIN Qiang
Received date: 2025-01-15
Revised date: 2025-02-12
Online published: 2025-02-21
Supported by
National Key Research and Development Program of China(2022YFC3103800)
Science and Technology Projects of Guangzhou(2025A04J5494)
Science and Technology Projects of Guangzhou(2023A04J0191)
Internal solitary waves (ISWs) west of Dongsha islands in the northern South China Sea (SCS) were studied using acoustic backscatter data collected in August 2021. Satellite images and XBT profiles obtained simultaneously were integrated to analyze the propagation and evolution processes of ISWs at depths 110~180 m. A comparison between acoustic backscatter images and concurrent XBT profiles revealed that acoustic imaging captured fine-scale water structures with minimal discrepancies in the upper 150 m. The acoustic section captured three soliton trains (ISW1, ISW2, and ISW3) with distinct vertical and horizontal scales of -20~30 m and -160~380 m, respectively. Their propagation speeds were 1.0, 1.2, and 1.5 m·s-1, respectively. The observed characteristics of ISWs align more closely with predictions from theoretical two-layer Korteweg-de Vries (KdV) models. ISW1 displays complex waveform characteristics, while ISW3 exhibits an asymmetric waveform structure influenced by slope topography, suggesting strong dissipation in both cases. The combination of high-resolution acoustic and hydrographic techniques provides a comprehensive approach to overcoming the limitations of single-instrument measurements, enhancing our understanding of the complex propagation processes of ISWs in the northern SCS.
XIONG Xin , FENG Yingci , YANG Renhui , SUN Jie , LI Jian , ZHAN Wenhuan , LYU Kaiyun . Study on the characteristics of internal solitary waves in the Dongsha area of the northern South China Sea based on acoustic backscatter data*[J]. Journal of Tropical Oceanography, 2025 , 44(3) : 14 -23 . DOI: 10.11978/2025010
图 4 研究区域温度、盐度、密度和浮力频率深度剖面a. 研究区温度剖面, 红色曲线为12年区域8月份平均温度剖面, 灰色曲线为研究区历史温度剖面, 蓝色和黑色分别代表XBT1和XBT2温度剖面; b. 研究区盐度剖面, 红色曲线为12年区域8月份平均盐度剖面, 灰色曲线为研究区历史盐度剖面; c. 根据历史平均温盐剖面计算得到的研究区密度剖面; d. 根据密度数据计算得到的研究区浮力频率剖面 Fig. 4 Depth profiles of temperature, salinity, density and buoyancy frequency in the study area |
表1 内孤立波的观测参数*Tab. 1 Observed parameters of internal solitary waves |
内孤立波 | 经度 | 纬度 | 时间 | 水深/m | 振幅/m |
---|---|---|---|---|---|
ISW1 | 115°30′06.7″E | 21°18′55.3″N | 10:16:37 | 114.3 | 20 |
ISW2 | 115°29'40.5″E | 21°03'37.3″N | 11:06:49 | 119.8 | 31 |
ISW3 | 115°33'01.6″E | 20°56'45.6″N | 12:43:04 | 179.0 | 19 |
注: *量取首个大振幅内孤立波的波谷。 |
图 6 内孤立波(ISW1)声学背散射图像Fig. 6 Magnified view of acoustic backscatter image showing ISW1 |
表 2 内孤立波观测和模型参数Tab. 2 Internal solitary waves observation and model parameters |
ISW | 观测振幅 /m | 观测半波宽度 /m | 校正后半波宽度 L/m | 观测传播速度 /(m·s-1) | 理论计算模型 | 理论特征宽度Δ/m | 解析比L/Δ (理论值1.76) | 模型理论传播速度/(m·s-1) |
---|---|---|---|---|---|---|---|---|
ISW2 | 31 | 155 | 168 | 1.2 | 双层KdV模型 | 94 | 1.79 | 1.0 |
双层eKdV模型 | 80 | 2.10 | 0.8 | |||||
连续层结KdV模型 | 52 | 3.23 | 0.7 | |||||
ISW3 | 19 | 307 | 380 | 1.5 | 双层KdV模型 | 209 | 1.82 | 1.1 |
双层eKdV模型 | 126 | 3.01 | 1.0 | |||||
连续层结KdV模型 | 285 | 1.33 | 0.6 |
[1] |
蔡树群, 牛建伟, 何映晖, 等, 2021. 基于海上风电场构建海洋水文同步实时现场观测系统的思考[J]. 热带海洋学报, 40(3): 96-102.
|
[2] |
崔海吉, 李志鑫, 张猛, 等, 2021. 南海东沙岛北部第二模态内孤立波特性研究[J]. 中国海洋大学学报(自然科学版), 51(11): 16-21.
|
[3] |
董崇志, 宋海斌, 郝天珧, 等, 2009. 南海东北部海洋内波的反射地震研究[J]. 地球物理学报, 52(8): 2050-2055.
|
[4] |
邝芸艳, 王亚龙, 宋海斌, 等, 2021. 南海东北部内孤立波包的地震海洋学和遥感研究[J]. 地球物理学报, 64(2): 597-611.
|
[5] |
宋海斌, 邝芸艳, 杨胜雄, 等, 2023. 东沙海域内孤立波浅化过程及含圈闭涡核内孤立波的反射地震初探[J]. 地球物理学报, 66(1): 344-356.
|
[6] |
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[J]. 地球物理学报, 62(7): 2622-2632.
|
[7] |
田壮才, 郭秀军, 余乐, 等, 2018. 内孤立波悬浮海底沉积物研究进展[J]. 地球科学进展, 33(2): 166-178.
|
[8] |
王振霄, 王彩霞, 2019. 基于遥感图像的南海北部内孤立波及相互作用研究[J]. 海洋与湖沼, 50(5): 958-970.
|
[9] |
谢波涛, 黄必桂, 杨威, 等, 2023. 南海北部东沙岛以西陆坡区2021年秋季内波特征统计与分析[J]. 热带海洋学报, 42(6): 29-41
|
[10] |
杨胜雄, 邱燕, 朱本铎, 2015. 南海地质地球物理图系[M]. 天津: 中国航海图书出版社.
|
[11] |
郑全安, 陈亮, 熊学军, 等, 2022. 南海内波研究前沿与热点[J]. 海洋科学进展, 40(4): 564-580.
|
[12] |
|
[13] |
|
[14] |
|
[15] |
|
[16] |
|
[17] |
|
[18] |
|
[19] |
|
[20] |
|
[21] |
|
[22] |
|
[23] |
|
[24] |
|
[25] |
|
[26] |
|
[27] |
|
[28] |
|
[29] |
|
[30] |
|
[31] |
|
[32] |
|
[33] |
|
[34] |
|
[35] |
|
[36] |
|
[37] |
|
/
〈 |
|
〉 |