Characteristics and generations of internal wave in the Sulu Sea inferred from optical satellite images

• Published in: Journal of oceanology and limnology Vol. 38; no. 5; pp. 1435 - 1444
• Main Authors: Zhang, Xudong, Li, Xiaofeng, Zhang, Tao
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.09.2020; Springer Nature B.V; College of Geomatics, Shandong University of Science and Technology, Qingdao 266071, China; CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences and Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China%CAS Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences and Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
• Subjects: Archipelagoes; Chemical analysis; Contamination; Earth and Environmental Science; Earth Sciences; evolution; exhibitions; image analysis; Imaging radiometers; Imaging techniques; Infrared imaging; Infrared radiometers; Internal tides; Internal waves; islands; length; Limnology; Oceanography; Propagation; Radiometers; Radiometry; Ray tracing; remote sensing; Satellite imagery; Satellite observation; satellites; Science; Seasonal variation; Seasonal variations; Seawater; Sensors; Spectroradiometers; Straits; Water analysis; Wave crest; Wave crests; Sulu Sea; Suomi National Polar-Orbiting Partnership (NPP); internal waves (IWs); Sulu Sea; Moderate-Resolution Imaging Spectroradiometer (MODIS)
• ISSN: 2096-5508; 2523-3521
• DOI: 10.1007/s00343-020-0046-1

Characteristics and generation of internal waves (IWs) in the Sulu Sea are studied using Moderate-Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) images taken from October 2016 to September 2019. Satellite observations show that IWs in the Sulu Sea mainly located in the shallower western areas with occasional observations in the deeper eastern regions. The dominant length of wave crest (LWC) of IWs is between 50 and 150 km with the largest LWC reaching over 300 km. The analysis of temporal distributions of IWs shows that March has the most IWs and July has the least. Further analysis shows that the seasonal variation is mainly due to the cloud contamination of optical satellite images. New generation sites of IWs are analyzed using satellite images. Six possible generation sites for IWs in the western Sulu Sea and one generation site for IWs in the eastern Sulu Sea are found using the ray-tracing method. Multi IW sources in the same strait are found, which may be due to the seawater fl ow over the strait in diff erent directions. The analysis shows that IWs with long wave crest in the Sulu Sea is a combined eff ort of all straits between small islands in the Sulu Archipelago. Remote generated IWs with long wave crest in the eastern Sulu Sea are studied, which are generated at the straits around (121.5°E, 6°N) by the nonlinear evolution of internal tide originated from the Sulu Archipelago.