Characteristics of Internal Solitary Waves in the Timor Sea Observed by SAR Satellite

Abstract

Internal solitary waves (ISWs) with features such as large amplitude, short period, and fast speed have great influence on underwater thermohaline structure, nutrient transport, and acoustic signal propagation. The characteristics of ISWs in hotspot areas have been revealed by satellite images combined with mooring observation. However, the ISWs in the Timor Sea, which is located in the outflow of the ITF, have not been studied yet and the characteristics are unrevealed. In this study, by employing the Synthetic Aperture Radar (SAR) images taken by the Sentinel-1 satellite from 2017 to 2022, the temporal and spatial distribution characteristics of ISWs in the Timor Sea are analyzed. The results show that most of ISWs appear in Bonaparte basin and its vicinity. The average wavelength of the ISWs is 248 m, and most of the wave lengths are less than 400 m. The peak line of ISWs is longer in deeper water. The underwater structures of two typical ISWs are reconstructed based on the Korteweg–de Vries (KdV) equation combined with mooring observation. This shows that, compared with the two-layer model, the continuous layered model is more suitable for reconstructing the underwater structures of ISWs. Further analysis shows that both the rough topography and the spring-neap tides contribute to the generation of ISWs in the Timor Sea. This study fills a gap in knowledge of ISWs in regional seas, such as the Timor Sea.

Strongly Nonlinear Effects on Determining Internal Solitary Wave Parameters From Surface Signatures With Potential for Remote Sensing Applications

“…A retrieval method based on the Korteweg-de Vries (KdV) equation was proposed (Small et al, 1999;Zheng et al, 2001) and widely used for determining ISW parameters from the distribution of bright-dark stripes (Fan et al, 2015;Gong et al, 2021;Peng et al, 2023;Phaniharam et al, 2020;Purwandana & Cuypers, 2023;Wang et al, 2022;Xie et al, 2022;Zhang et al, 2023). Similarly to the former, retrieval methods using the Joseph-Kubota-Ko-Dobbs (JKKD) equation for finite depth (Pan et al, 2007), the Benjamin-Ono (BO) equation for infinite depth (Chen et al, 2011(Chen et al, , 2023Wang et al, 2019) and the extended KdV (eKdV) equation (Jia et al, 2019;Xue et al, 2013) were also proposed to analyze satellite images.…”