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Observed Variability of Surface Layer in the Central Bay of Bengal:Results of Measurements Using Glider


Affiliations
1 National Institute of Ocean Technology, Ministry of Earth Sciences, Pallikaranai, Chennai 600 100, India
2 College of Engineering, Guindy Campus, Anna University, Chennai 600 025, India
 

Underwater gliders measure high-resolution spatiotemporal oceanographic data. In April 2014, the National Institute of Ocean Technology, Chennai operated an underwater glider ‘Barathi’, for 127 days for observation of Bay of Bengal (BoB). In this article we present the effectiveness of the glider Barathi for high resolution temporal sampling of the surface layer in the central BoB for studying variation of temperature, salinity and density structures and acoustic characteristics on 26–27 May 2014. The results showed ‘afternoon effect’ on acoustic characteristics and formation of secondary sound channel. Our data set is strongly correlated (coefficient of determination r2 > 0.96) with data from a nearby Array for real-time geostrophic Oceanography (Argo) float.

Keywords

Bay of Bengal, Density, Eddy, Glider, Salinity, SLD, MLD, Ocean Observation, Temperature.
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  • Siderius, M., Porter, M. B., Hurskey, P., McDonald, V. and the KauaiEx Group, Effects of ocean thermocline variability on non-coherent underwater acoustic communications, J. Acoust. Soc. Am., 2007, 121, 1895–1908.

  • Sutton, P. J., Worcester, P. F., Masters, G., Cornuelle, B. D. and Lynch, J. F., Ocean mixed layers and acoustic pulse propagation in the Greenland Sea. J. Acoust. Soc. Am., 1993, 94, 1517–1526.

  • Hareesh Kumar, P. V., The sound channel characteristics in the south central Bay of Bengal. Int. J. Innov. Technol. Exp. Eng., ISSN: 2278-3075, 2013, 3(6), 61–65.

  • Prasannakumar, S., Murty, T. V. R., Somayajulu, Y. K., Chodankar, P. V. and Murty, C. S., Reference sound speed profile and related ray acoustics of Bay of Bengal for tomographic studies. Acta Acustica, 1994, 80, 127–137.

  • Prasannakumar, S., Somayajulu, Y. K. and Murty, T. V. R., Acoustic propagation characteristics and tomography studies of the northern Indian Ocean, In Acoustic Remote Sensing Applications (ed. Singal, S. P.), Narosa, New Delhi, 1997, pp. 551–581.

  • Murty, T. V. R., Somayajulu, Y. K. and Sastry, J. S., Computations of some acoustic ray parameters in the Bay of Bengal. Indian J. Mar. Sci., 1990, 19, 235–245.

  • Murty, T. V. R., Somayajulu, Y. K. and Sastry, Simulation of acoustic propagation along a section in the western Bay of Bengal. J. Pure Appl. Ultra., 1990, 12, 29–33.

  • Murty, T. V. R. et al., Objective mapping of observed sub-surface mesoscale cold core eddy in the Bay of Bengal by stochastic inverse technique with tomographically simulated travel times. Indian J. Geo. Mar. Sci., 2011, 40, 307–324.

  • Udaya Bhaskar, T. V. S., Debadatta Swain and Ravichandran, M., Sonic layer depth variability in the Arabian Sea. Int. J. Oceans Oceanogr., 2010, 4, 17–28.

  • Udaya Bhaskar, T. V. S., Swain, D., Ravichandran, M., Inferring mixed-layer depth variability from Argo observation in the western Indian Ocean. J. Mar. Res., 2006, 64, 393–406.

  • Udaya Bhaskar, T. V. S., Swain, D. and Ravichandran, M., Mixed layer variability in the Northern Arabian Sea as detected by an Argo float. Ocean Sci. J., 2007, 42(4), 241–246.

  • Udaya Bhaskar, T. V. S., Swain, D. and Ravichandran, M., Seasonal variability of Sonic Layer depth in the central Arabian Sea. Ocean Sci. J., 2008, 43(3), 147–152.

  • Farrar, J. T., Zappa, C. J., Weller, R. A. and Jessup, A. T., Sea surface temperature signatures of oceanic internal waves in low winds. J. Geophys. Res. Oceans, 2007, 112, C06014.

  • Walsh, E. J. et al., Coupling of internal waves on the main thermocline to the diurnal surface layer and sea surface temperature during the tropical Ocean – global atmosphere coupled ocean–atmosphere response experiment. J. Geophys. Res., 1998, 103, 12,612–12,628.

  • Benjamin, A., Hodges and David M. Fratantoni, AUV observations of the diurnal surface layer in the north Atlantic salinity maximum. J. Phys. Oceanogr., 2014, 44, 1595–1604; doi:http://dx.doi.org/10.1175/JPO-D-13-0140.1.

  • http://auvac.org/explore-database/browse-database (accessed on 8 August 2014).

  • Ravichandran, P. N.. Vinayachandran, Sudheer Joseph and Radhakrishnan, K., Results from first ARGO float deployed by India. Curr. Sci., 2004, 86(5), 651–659.

  • http://www.jamstec.go.jp/ARGO/argo_web/results/system_building/deployment/weight_adjustment/TR-ballasting2.pdf (accessed on 1 May 2015).

  • Kobayahi, T. et al., Quality control of Argo data based on high quality climatological data set (HydroBase) I, http://www.jamstec.go.jp/ARGO/argo_web/results/data_management/management/quality_control_1/Quality_control.pdf (accessed on 19 January 2015).

  • http://www.ioos.noaa.gov/observing/observing_assets/glider_asset_map.html (accessed on 6th February 2015).

  • http://marine.rutgers.edu/cool/auvs/ (accessed on 6 February 2015).

  • http://www.incois.gov.in/portal/datainfo/insituhome.jsp (accessed on 6 February 2015).

  • Shijo Zacharia, et al., Glider operations in the Bay of Bengal. In proceedings of IEEE International Symposium on Underwater Technology, Chennai, India, 2015; doi: 10.1109/UT.2015.7108279.

  • Shijo Zacharia, et al., Initial set of oceanographic data from Bay of Bengal by means of an underwater glider as mobile sensor node. Curr. Sci., 2015, 109(5), 918–928.

  • Stommel, H., The Slocum mission. Oceanography, 1989, l(2), 22–25.

  • Bachmayer, R., Leonard, N. E., Graver, J., Fiorelli, E., Battha, P. and Palley, D., Underwater gliders: recent developments and future applications. In proceedings of the IEEE International Symposium on Underwater Technology. Taipei, Taiwan, 2004.

  • Rudnick, D. L., Davis, R. E., Eriksen, C. C., Fratantoni, D. M. and Perry, M. J., Underwater gliders for ocean research. Mar. Tech. Soc. J., 2004, 38, 73–84; doi:10.4031/002533204787522703.

  • http://www.webbresearch.com/pdf/Slocum_Glider_Data_Sheet.pdf (accessed on 6 February 2015).

  • http://las.aviso.oceanobs.com/las/getUI.do (accessed on 6 February 2015).

  • http://las.incois.gov.in/ (accessed on 6 February 2015).

  • http://www.argo.ucsd.edu/Argo_GE.html (accessed on 6 February 2015).

  • Oka, E. Ando, K., Stability of temperature and conductivity sensors of Argo profiling floats. J. Oceanogr., 2004, 60, 253–258.

  • http://ftp.seabird.com/products/spec_sheets/41data.html (accessed on 6 February 2015).

  • http://www.incois.gov.in/portal/datainfo/mooredpositions.html (accessed on 6 February 2015).

  • Venkatesan, R. et al., In situ ocean subsurface time-series measurements from OMNI buoy network in the Bay of Bengal. Curr. Sci., 2013, 104(9), 1166–1177.

  • Fofonoff, P. and Millard Jr, R. C., Algorithms for computation of fundamental properties of seawater. Unesco Tech. Pap. Mar. Sci., 1983, 44, 46–49.

  • Etter, C. P., Underwater Acoustic Modelling: Principles, Techniques and Applications. E&FN Spon, London, 2nd edn, 1996, p. 88.

  • Jain, S., Ali, M. M. and Sen, P. N., Estimation of sonic layer depth from surface parameters. Geophys. Res. Lett., 2007, 34, L17602; doi:10.1029/2007GL030577.

  • Urick, R. J., Principles of underwater sound. McGraw-Hill, New York, USA, 1983, 3rd edn, p. 423.

  • Ohno, Y., Kobayashi, T., Iwasaka, N. and Suga, T., The mixed layer depth in the North Pacific as detected by the Argo floats. Geophys. Res. Lett., 2004, 31, L11306; doi:10.1029/2004 GL019576.

  • McGillicuddy Jr, D. J., Johnson, R., Siegel, D. A., Michaels, A. F., Bates, N. R. and Knap, A. H., Mesoscale variations of biochemical properties in the Sargasso Sea. J. Geophys. Res., 1999, 104(C6), 13381–13394; http://dx.doi.org/10.1029/1999JC900021.

  • Hwang, C., Wu, C. R. and Kao, R., TOPEX/poseidon observations of mesoscale eddies over the subtropical countercurrent: kinematic characteristics of an anticyclonic eddy and a cyclonic eddy. J. Geophys. Res., 2004, 109, C08013; doi:10.1029/2003JC002026.

  • Tomczak, M. and Godfrey, J. S., Regional Oceanography: An Introduction, 2001, Chapter 12, http://www.es.flinders.edu.au/~mattom/regoc/pdffiles/colour/single/12P-Indian.pdf (accessed on 6 February 2015).

  • http://www.incois.gov.in/Images/iogoos/abstracts/abstract1.htm (accessed on 6 February 2015).

  • Gopalan, A. K. S., Gopala Krishna, V. V., Ali, M. M. and Sharma Rashmi, Detection of Bay of Bengal eddies from TOPEX and in situ observations. J. Mar. Res., 2000, 58, 721–734.

  • Isern-Fontanet, J., Garcia-Ladona, E. and Font, J., Vortices of the mediterranean sea: an altimetric perspective. J. Phys. Oceanogr., 2006, 36, 87–103.

  • Hu, J., Gan, J., Sun, Z., Zhu, J. and Dai, M., Observed three‐dimensional structure of a cold eddy in the southwestern South China Sea. J. Geophys. Res., 2011, 116, C05016; doi:10.1029/2010JC006810.

  • Richard, P., Hodges, Underwater Acoustics Analysis, Design and Performance of SONAR. John Wiley & Sons, Ltd, New Delhi, India, 2010, p. 227.

  • Lowrence E. Kinsler, Austin R. Frey, Alan B. Coppens, James V. Sanders, Fundamentals of Acoustics, John Wiley & Sons, Inc, New York, USA, 2000, 4th edn, p. 440.

  • Chow, R. K. and Browning, D. G., A study of secondary sound channels due to temperature inversions in the Northeast Pacific Ocean. J. Acoust. Soc. Am., 1982, 72, S57; http://dx.doi.org/10.1121/1.2019957.

  • Robert, W. H., Barron, C. N., Cames, M. R. and Zingareli, R. A., Evaluating the sonic layer depth relative to the mixed layer depth. J. Geophys. Res., 2008, 113, C07033; doi:10.1029/2007/JC004595.


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  • Observed Variability of Surface Layer in the Central Bay of Bengal:Results of Measurements Using Glider

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Authors

Shijo Zacharia
National Institute of Ocean Technology, Ministry of Earth Sciences, Pallikaranai, Chennai 600 100, India
R. Seshasayanan
College of Engineering, Guindy Campus, Anna University, Chennai 600 025, India
Tata Sudhakar
National Institute of Ocean Technology, Ministry of Earth Sciences, Pallikaranai, Chennai 600 100, India
M. A. Atmanand
National Institute of Ocean Technology, Ministry of Earth Sciences, Pallikaranai, Chennai 600 100, India
R. R. Rao
National Institute of Ocean Technology, Ministry of Earth Sciences, Pallikaranai, Chennai 600 100, India

Abstract


Underwater gliders measure high-resolution spatiotemporal oceanographic data. In April 2014, the National Institute of Ocean Technology, Chennai operated an underwater glider ‘Barathi’, for 127 days for observation of Bay of Bengal (BoB). In this article we present the effectiveness of the glider Barathi for high resolution temporal sampling of the surface layer in the central BoB for studying variation of temperature, salinity and density structures and acoustic characteristics on 26–27 May 2014. The results showed ‘afternoon effect’ on acoustic characteristics and formation of secondary sound channel. Our data set is strongly correlated (coefficient of determination r2 > 0.96) with data from a nearby Array for real-time geostrophic Oceanography (Argo) float.

Keywords


Bay of Bengal, Density, Eddy, Glider, Salinity, SLD, MLD, Ocean Observation, Temperature.

References





DOI: https://doi.org/10.18520/cs%2Fv113%2Fi11%2F2151-2159