Abstract
In the early morning of 21 April 2021 local time, the Indonesian Navy submarine KRI nanggala-402 crashed in the Bali Sea (BS). As internal solitary waves (ISWs) are a great threat to submarine navigation, this paper analyzes the characteristics of ISWs in the BS by surveying satellite remote sensing images collected from 12–21 April 2021. The satellite images revealed active ISWs in the BS near the submarine wreck site with crest lengths approaching 200 km. Originating from the Lombok Strait (LS), the waves travelled northwestward across the BS deep basin, passed through the submarine wreck site, and shoaled onto the continental shelf west of the Kangean Islands, during which process, the propagation speed reached 2.69 m/s in the deep basin and 0.71 m/s in the shallow water. Based on the satellite images, the wave amplitude near the wreck site was reconstructed to be 41 m, and the reconstructed underwater wave structure showed a maximum vertical velocity of 10 cm/s. Satellite images also demonstrated the near-source evidence of ISWs near the Nusa Penida sill of the LS, and their generation were estimated to be related to the southward tidal current troughs.
Highlights
Internal solitary waves (ISWs) are the nonlinear short-period waves widely distributed in the global oceans [1,2,3,4,5,6,7,8]
By surveying remote sensing images over the Bali Sea (BS), we found significant ISW activities near the submarine KRI nanggala-402 wreck site in April 2021
Those ISWs were generated in the Lombok Strait (LS) and traveled along the north-western direction in the BS basin, passing through the submarine wreck site, and reached the continental shelf to the west of the Kangean Islands
Summary
Internal solitary waves (ISWs) are the nonlinear short-period waves widely distributed in the global oceans [1,2,3,4,5,6,7,8]. Featuring large amplitudes and strong currents, ISWs in the oceans are considered as one of the major threats to submarine navigation [10]. ISWs have the ability to cause strong density disturbances that can suddenly decrease the buoyancy of a submarine, resulting in a large depth drop in a very short time. In the early morning of 21 April 2021 local time (near 4:30 AM), the Indonesian Navy’s submarine (KRI nanggala-402) crashed in the BS and all 53 crew members were died. We collected the optical remote sensing images covering BS during those days and investigated the distribution, propagation and underwater structure of ISWs around the time of the KRI nanggala-402 wreck
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
