Variability of Internal Solitary Waves Detection in the Lombok Strait Observed by Sentinel-1 SAR: The Role of Monsoon, IOD, and ENSO

Six years of Synthetic Aperture Radar (SAR) data were employed to analyze the detection variability of Internal Solitary Waves (ISW) in the Lombok Strait when the Indian Ocean Dipole (IOD) and the El Niño-Southern Oscillation (ENSO) occurs from 2015 to 2020. Sentinel-1 SAR images were employed to investigate the annual and monthly distribution frequency in the Lombok Strait. The annual distribution of ISW signatures detection shows an inter-annual variability, indicating long-term modification process. ISW detection frequencies increased during Positive IOD in 2019 and decreased during La Nina events in 2020 in Indonesian seas. ISW detection for the monsoonal variation is often detected during the South East Monsoon (SEM) when the southward through-flow exists in the generation site. The monthly distribution reveals that the highest frequency in October is as high as 53% and the lowest frequency in June is as low as 37% over a six-year period. The potential cause of variability depends on the difference in the thermocline’s depth, which indirectly affects the amplitude and wavelength of the ISW.