Authors: Chonnaniyah, Eko Siswanto, Abd. Rahman As-syakur, and Takahiro Osawa
Journal: Journal of Sea Research
Internal waves are easily recognized features of remote sensing images. They occur below the sea surface and can be observed using optical and radar sensors due to their interactions with surface waves. Nonlinear internal waves, known as Internal Solitary Waves (ISW), maintain their coherence and visibility through nonlinear hydrodynamics and appear as long quasilinear stripes in images. Optical sensors can capture changes in sea surface roughness modulated by ISW when their location is close to specular reflection from the sun. Optical imagery with wide area coverage and high temporal resolution has the potential to track and analyze ISW dynamics. However, a comprehensive analysis of the mechanisms underlying ISW manifestation patterns in optical images is necessary. The GCOM-C/SGLI satellite, equipped with a visible-near infrared radiometer and an infrared scanner, provides a detailed view of ISW manifestations using various scanning techniques. By analyzing SGLI products that detect ISW patterns, this study investigated how these waves manifest on the sea surface. The comparison between Level-1B data and Level-2 Ocean products observed by the SGLI sensor reveals that ISW patterns significantly affect ocean color parameters and thermal channel data. The consistent ISW manifestation pattern detected in TOA radiance and ocean color products suggests that ISWs impact sea surface roughness. Additionally, the detection of ISW patterns in SST data is a notable finding, highlighting the potential influence of ISWs on air-sea interactions and the atmospheric boundary layer. Understanding these impacts is crucial for remote sensing applications, particularly for long-term internal wave monitoring and ensuring that smaller-scale internal wave signals do not interfere with large-scale satellite estimations of ocean color.
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Fig. 7: Flowchart of the comprehensive method used in this study. The grayed-out files were SGLI channels and the products analyzed in this study were adapted from Ogata et al. (2017). The blue box represents the TOA radiance for the spectral characteristics, and the green boxes represent the ocean color products. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) |
