Abstract
The presence of large-amplitude Internal Solitary Waves (ISWs or solitons) is quite common in the Andaman Sea, located in the north-eastern Indian Ocean basin. ISWs are known to induce strong vertical velocities which can play an essential role in the mixing transport of nutrients and are proven hazardous to offshore oil platforms. The surface signatures of ISWs can be detected using remote sensing instruments like Synthetic Aperture Radar (SAR) and sunglint true-colour images. The present study makes an effort to delineate as well as detect the possible potential generation locations of mode-1 long living ISWs in the Andaman Sea using remote sensing observations. To accomplish this, the Moderate Resolution Imaging Spectroradiometer (MODIS) true-colour images of Terra/Aqua satellites for the months of March and April during 2014–2016 are used to map the distribution and propagation characteristics of ISWs. These maps along with SAR imgaes from ENVISAT and TerraSAR-X are used to detect the possible generation locations of ISWs. The study considers the possible generation location of ISW as the circumcentre of each wave packet as they radially propagate along a two-dimensional frame. The analysis reveals five potential ISW generation hotspots that are distributed along the Northern Andaman Sea, as well as locations in the discontinuities off the Nicobar Islands and the great passage. The ISWs that form over these regions are hitting the continental shelf within the Andaman Sea. Interestingly, the waves from two potential generation sites between the Nicobar Islands appear to radiate waves in two opposite directions, towards the Andaman Sea and the southern Bay of Bengal.
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References
Alford, M.H., Thomas, P., Jennifer, A.M.,Jonathan, D.N., Maarten, C.B., Luca, R.C. et al. (2015). The formation and fate of internal waves in the South China Sea. Nature, 521, 65–69. https://doi.org/10.1038/nature14399.
Alpers, W., Wang-Chen, H., & Hock, L. (1997). Observation of internal waves in the Andaman Sea by ERS SAR. In Geoscience and Remote Sensing, 1997. IGARSS’97. Remote Sensing-A Scientific Vision for Sustainable Development., 1997 IEEE International (Vol. 4, pp. 1518–1520).
Apel, J. R., Ostrovsky, A. A., Stepanyants, A. A., Lynch, A. F., Ostrovsky, L. A., Stepanyants, Y. A., & Lynch, J. F. (2007). Internal solitons in the ocean and their effect on underwater sound. The Journal of the Acoustical Society of America, (98), 121. https://doi.org/10.1121/1.2395914͔.
Azevedo, A., Da Silva, J. C. B., & New, A. L. (2006). On the generation and propagation of internal solitary waves in the southern Bay of Biscay. Deep Sea Research Part I: Oceanographic Research Papers, 53(6), 927–941.
Baines, P. G. (1982). On internal tide generation models. Deep Sea Research Part A. Oceanographic Research Papers, 29(3), 307–338.
da Silva, J.C.B., Magalhaes, J.M. (2016). Internal solitons in the Andaman Sea: a new look at an old problem. Proceedings of the SPIE, Vol. 9999, 13 pp, https://doi.org/10.1117/12.2241198
Hyder, P., Jeans, D. R. G., Cauquil, E., & Nerzic, R. (2005). Observations and predictability of internal solitons in the northern Andaman Sea. Applied Ocean Research, 27(1), 1–11.
Jackson, C. R. (2004). An atlas of internal solitary-like waves and their properties.
Jackson, C. (2007). Internal wave detection using the moderate resolution imaging spectroradiometer (MODIS). Journal of Geophysical Research: Oceans, 112(C11).
Jackson, C. R., Da Silva, J. C. B., & Jeans, G. (2012). The generation of nonlinear internal waves. Oceanography, 25.
Lozovatsky, I., Liu, Z., Fernando, H., Armengol, J., & Roget, E. (2012). Shallow water tidal currents in close proximity to the seafloor and boundary-induced turbulence. Ocean Dynamics, 62(2), 177–191.
Magalhães, J.M., Da Silva, J.C.B., Buijsman, M.C. & Garcia, C.A.E. (2016). Effect of the North Equatorial Counter Current on the generation and propagation of internal solitary waves off the Amazon shelf (SAR observations). Ocean Science, 12(1), pp.243–255
Magalhaes, J. M., & da Silva, J. (2018). Internal solitary waves in the Andaman Sea : new insights from SAR imagery. Remote Sensing, 10(6), 861. https://doi.org/10.3390/rs10060861.
Osborne, A. R., & Burch, T. L. (1980). Internal solitons in the Andaman Sea. Science (New York, N.Y.), 208(4443), 451–460. https://doi.org/10.1126/science.208.4443.451.
Sachiko, M., Rao, A. D., & Latha, G. (2018). Energetics of semidiurnal internal tides in the Andaman Sea. Journal of Geophysical Research: Oceans, 123(9), 6224–6240. https://doi.org/10.1029/2018JC013852.
Shimizu, K., & Nakayama, K. (2017). Effects of topography and Earth’s rotation on the oblique interaction of internal solitary-like waves in the Andaman Sea. Journal of Geophysical Research: Oceans, 122(9), 7449–7465.
Sindhu B, Unnikrishnan AS. (2013). Characteristics of tides in the Bay of Bengal. Marine Geodesy, 36, 377–407. https://doi.org/10.1080/01490419.2013.781088.
Sindhu, B., Suresh, I., Unnikrishnan, a. S., Bhatkar, N. V., Neetu, S., & Michael, G. S. (2007). Improved bathymetric datasets for the shallow water regions in the Indian Ocean. Journal of Earth System Science, 116(3), 261–274. https://doi.org/10.1007/s12040-007-0025-3.
Vlasenko, V., Alpers, W. (2005). Generation of secondary internal waves by the interaction of an internal solitary wave with an underwater bank. Journal of Geophysical Research: Oceans, 110, C02019, https://doi.org/10.1029/2004JC002467
Warn-Varnas, A., Ko, D. S., & Gangopadhyay, A. (2015). Signatures of tidal interference patterns in the South China Sea. Journal of Oceanography, 71(3), 251–262.
Wijeratne, E. M. S., Woodworth, P. L., & Pugh, D. T. (2010). Meteorological and internal wave forcing of seiches along the Sri Lanka coast. Journal of Geophysical Research, 115(C3), C03014. https://doi.org/10.1029/2009JC005673.
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Authors are very thankful to the European Space Agency, German Aerospace Centre, and Airbus Defence and Space for providing the synthetic-aperture radar data. MODIS imagery is a courtesy of NASA through NASA Worldview.
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Raju, N., Dash, M.K., Dey, S.P. et al. Potential generation sites of internal solitary waves and their propagation characteristics in the Andaman Sea—a study based on MODIS true-colour and SAR observations. Environ Monit Assess 191 (Suppl 3), 809 (2019). https://doi.org/10.1007/s10661-019-7705-8
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DOI: https://doi.org/10.1007/s10661-019-7705-8