Oceanography The Official Magazine of
The Oceanography Society
Volume 29 Issue 02

View Issue TOC
Volume 29, No. 2
Pages 38 - 49

Representation of Bay of Bengal Upper-Ocean Salinity in General Circulation Models

Jasti S. ChowdaryG. SrinivasT.S. FousiyaAnant ParekhC. Gnanaseelan Hyodae Seo Jennifer A. MacKinnon
Article Abstract

The Bay of Bengal (BoB) upper-ocean salinity is examined in the National Centers for Environmental Prediction-Climate Forecasting System version 2 (CFSv2) coupled model, Modular Ocean Model version 5 (MOM5), and Indian National Centre for Ocean Information Services Global Ocean Data Assimilation System (INC-GODAS). CFSv2 displays a large positive salinity bias with respect to World Ocean Atlas 2013 in the upper 40 m of the water column. The prescribed annual mean river discharge and excess evaporation are the main contributors to the positive bias in surface salinity. Overestimation of salinity advection also contributes to the high surface salinity in the model during summer. The surface salinity bias in MOM5 is smaller than in CFSv2 due to prescribed local freshwater flux and seasonally varying river discharge. However, the bias is higher around 70 m in summer and 40 m in fall. This bias is attributed to excessive vertical mixing in the upper ocean. Despite the fact that representation of salinity in INC-GODAS is more realistic due to data assimilation, the vertical mixing scheme still imposes systematic errors. The small-scale processes that control oceanographic turbulence are not adequately resolved in any of these models. Better parameterizations based on dedicated observational programs may help improve freshwater representation in regional and global models. 

Citation

Chowdary, J.S., G. Srinivas, T.S. Fousiya, A. Parekh, C. Gnanaseelan, H. Seo, and J.A. MacKinnon. 2016. Representation of Bay of Bengal upper-ocean salinity in general circulation models. Oceanography 29(2):38–49, https://doi.org/10.5670/oceanog.2016.37.

References

Adler, R.F., G.J. Huffman, A. Chang, R. Ferraro, P. Xie, J. Janowiak, B. Rudolf, U. Schneider, S. Curtis, D. Bolvin, and others. 2003. The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979–present). Journal of Hydrometeorology 4:1,147–1,167, https://doi.org/10.1175/1525-7541(2003)004<1147:TVGPCP>2.0.CO;2.

Agarwal, N., R. Sharma, A. Parekh, S. Basu, A. Sarkar, and V.K. Agarwal. 2012. Argo observations of barrier layer in the tropical Indian Ocean. Advances in Space Research 50:642–654, https://doi.org/​10.1016/j.asr.2012.05.021.

Akhil, V.P., F. Durand, M. Lengaigne, J. Vialard, M.G. Keerthi, V.V. Gopalakrishna, C. Deltel, F. Papa, and C. de Boyer Montégut. 2014. A modeling study of the processes of surface salinity seasonal cycle in the Bay of Bengal. Journal of Geophysical Research 119:3,926–3,947, https://doi.org/10.1002/2013JC009632.

Azaneu, M., R. Kerr, and M. Mata. 2014. Assessment of the representation of Antarctic Bottom Water properties in the ECCO2 reanalysis. Ocean Science 10:923–946, https://doi.org/10.5194/os-10-923-2014.

Behara, A., and P.N. Vinayachandran. 2016. An OGCM study of the impact of rain and river water forcing on the Bay of Bengal. Journal of Geophysical Research 121:2,425–2,446, https://doi.org/​10.1002/2015JC011325.

Benshila, R., F. Durand, S. Masson, R. Bourdallé-Badie, C. de Boyer Montégut, F. Papa, and G. Madec. 2014. The upper Bay of Bengal salinity structure in a high resolution model. Ocean Modelling 74:36–52, https://doi.org/10.1016/​j.ocemod.2013.12.001.

Brown, J.N., A. Sen Gupta, J.R. Brown, L.C. Muir, J.S. Risbey, P. Whetton, X. Zhang, B. Ganachaud, B. Murphy, and S.E. Wijffels. 2013. Implications of CMIP3 model biases and uncertainties for climate projections in the western tropical Pacific. Climate Change 119:147–161, https://doi.org/10.1007/s10584-012-0603-5.

Chowdary, J.S., A. Parekh, S. Ojha, and C. Gnanaseelan, and R. Kakatkar. 2016a. Impact of upper ocean processes and air-sea fluxes on seasonal SST biases over the tropical Indian Ocean in the NCEP Climate Forecasting System. International Journal of Climatology 36:188–207, https://doi.org/10.1002/joc.4336.

Chowdary, J.S., A. Parekh, G. Srinivas, C. Gnanaseelan, T.S. Fousiya, R. Khandekar, and M.K. Roxy. 2016b. Processes associated with the tropical Indian Ocean subsurface temperature bias in a coupled mode. Journal of Physical Oceanography, https://doi.org/10.1175/JPO-D-15-0245.1.

Dai, A., and K.E. Trenberth. 2002. Estimates of freshwater discharge from continents: Latitudinal and seasonal variations. Journal of Hydrometeorology 3:660–687, https://doi.org/​10.1175/1525-7541(2002)003<0660:EOFDFC>​2.0.CO;2

Dai, A., T. Qian, K.E. Trenberth, and J.D. Milliman. 2009. Changes in continental freshwater discharge from 1948 to 2004. Journal of Climate 22:2,773–2,791, https://doi.org/​10.1175/2008JCLI2592.1.

de Boyer Montégut, C., G. Madec, A.S. Fischer, A. Lazar, and D. Iudicone. 2004. Mixed layer depth over the global ocean: An examination of profile data and a profile-based climatology. Journal of Geophysical Research 109, C12003, https://doi.org/10.1029/2004JC002378.

Derber, J., and A. Rosati. 1989. A global oceanic data assimilation system. Journal of Physical Oceanography 19:1,333–1,347, https://doi.org/10.1175/1520-0485(1989)019<1333:AGODAS>2.0.CO;2.

Durand, F., F. Papa, A. Rahman, and S.K. Bala. 2011. Impact of Ganga-Brahmaputra interannual discharge variations on Bay of Bengal salinity and temperature during 1992–1999 period. Journal of Earth System Science 120:859–872, https://doi.org/10.1007/s12040-011-0118-x.

Durand, F., D. Shankar, F. Birol, and S.S.C. Shenoi. 2009. Spatiotemporal structure of the East India Coastal Current from satellite altimetry. Journal of Geophysical Research 114, C02013, https://doi.org/10.1029/2008JC004807.

Fousiya, T.S., A. Parekh, and C. Gnanaseelan. 2015. Interannual variability of upper ocean stratification in Bay of Bengal: Observational and modeling aspects. Theoretical and Applied Climatology 1–17, https://doi.org/10.1007/s00704-015-1574-z

Fox-Kemper, B., G. Danabasoglu, R. Ferrari, S.M. Griffies, R.W. Hallberg, M.M. Holland, M.E. Maltrud, S. Peacock, and B.L. Samuels. 2011. Parameterization of mixed layer eddies: Part III. Implementation and impact in global ocean climate simulations. Ocean Modelling 39:61–78, https://doi.org/10.1016/j.ocemod.2010.09.002.

Fox-Kemper, B., G. Danabasoglu, R. Ferrari, and R.W. Hallberg. 2008a. Parameterizing submesoscale physics in global climate models. CLIVAR Exchanges 13:3–5.

Fox-Kemper, B., R. Ferrari, and R.W. Hallberg. 2008b. Parameterization of mixed layer eddies: Part I. Theory and diagnosis. Journal of Physical Oceanography 38(6):1,145–1,165, https://doi.org/10.1175/2007JPO3792.1.

Gadgil, S., P.V. Joseph, and N.V. Joshi. 1984. Ocean atmosphere coupling over monsoon regions. Nature 312:141–143, https://doi.org/​10.1038/312141a0.

Gill, A.E. 1982. Atmosphere-Ocean Dynamics. Academic Press, San Diego, 662 pp.

Graham, N.E., and T.P. Barnett. 1987. Sea surface temperature, surface wind divergence, and convection over tropical oceans. Science 238:657–659, https://doi.org/10.1126/science.238.4827.657.

Griffies, S.M. 2012. Elements of the Modular Ocean Model (MOM): 2012 Release. GFDL Ocean Group Technical Report No. 7, Princeton, NJ, 631 pp.

Griffies, S.M., M.J. Harrison, R.C. Pacanowski, and A. Rosati. 2004. A Technical Guide to MOM4. GFDL Ocean Group Technical Report No. 5. Princeton, NJ, NOAA/Geophysical Fluid Dynamics Laboratory, 342 pp.

Howden, D.S., and R. Murtugudde. 2001. Effects of river inputs into the Bay of Bengal. Journal of Geophysical Research 106(C9):19,825–19,844, https://doi.org/10.1029/2000JC000656.

Jinadasa, S.U.P., I. Lozovatsky, J. Planella-Morató, J.D. Nash, J.A. MacKinnon, A.J. Lucas, H.W. Wijesekera, and H.J.S. Fernando. 2016. Ocean turbulence and mixing around Sri Lanka and in adjacent waters of the northern Bay of Bengal. Oceanography 29(2):170–179, https://doi.org/10.5670/oceanog.2016.49

Jochum, M., G. Briegleb, G. Danabasoglu, W.G. Large, N.J. Norton, S.R. Jayne, M.H. Alford, and F.O. Bran. 2013. The impact of oceanic near-inertial waves on climate. Journal of Climate 26:2,833–2,844, https://doi.org/10.1175/JCLI-D-12-00181.1.

Johnston, T.M.S., D. Chaudhuri, M. Mathur, D.L. Rudnick, D. Sengupta, H.L. Simmons, A. Tandon, and R. Venkatesan. 2016. Decay mechanisms of near-inertial mixed layer oscillations in the Bay of Bengal. Oceanography 29(2):180–191, https://doi.org/10.5670/oceanog.2016.50

Kanamitsu, M.W., J.W. Ebisuzaki, S.K. Yang, J.J. Hnilo, M. Fiorino, and G.L. Potter. 2002. NCEP-DEO AMIP-II reanalysis (R-2). Bulletin of American Meteorological Society 83:1,631–1,643, https://doi.org/10.1175/BAMS-83-11-1631.

Kara, A.B., P.A. Rochford, and H.E. Hurlburt. 2003. Mixed layer depth variability over the global ocean. Journal of Geophysical Research 108(C3), 3079, https://doi.org/10.1029/2000JC000736.

Large, W.G., J.C. McWilliams, and S.C. Doney. 1994. Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Reviews of Geophysics 32:363–403, https://doi.org/10.1029/94RG01872.

Large, W., and S. Yeager. 2004. Diurnal to Decadal Global Forcing for Ocean and Sea-Ice Models: The Data Sets and Flux Climatologies. NCAR Technical Note: NCAR/TN-460+STR. CGD Division of the National Center for Atmospheric Research, 112 pp.

Locarnini, R.A., A.V. Mishonov, J.I. Antonov, T.P. Boyer, H.E. Garcia, O.K. Baranova, M.M. Zweng, C.R. Paver, J.R. Reagan, D.R. Johnson, and others. 2013. World Ocean Atlas 2013, Volume 1: Temperature. S. Levitus, ed., A. Mishonov, technical ed., NOAA Atlas NESDIS 73, 40 pp.

Lucas, A.J., J.D. Nash, R. Pinkel, J.A. MacKinnon, A. Tandon, A. Mahadevan, M.M. Omand, M. Freilich, D. Sengupta, M. Ravichandran, and A. Le Boyer. 2016. Adrift upon a salinity-​stratified sea: A view of upper-ocean processes in the Bay of Bengal during the southwest monsoon. Oceanography 29(2):134–145, https://doi.org/10.5670/oceanog.2016.46.

MacKinnon, J.A., L. St. Laurent, and A. Naveira Garabato. 2013. Diapycnal mixing processes in the ocean interior. Pp. 159–184 in Ocean Circulation and Climate: A 21st Century Perspective. G. Siedler, S. Griffies, J. Gould, and J. Church, eds, Academic Press.

Mahadevan, A., G. Spiro Jaeger, M. Freilich, M. Omand, E.L. Shroyer, and D. Sengupta. 2016. Freshwater in the Bay of Bengal: Its fate and role in air-sea heat exchange. Oceanography 29(2):72–81, https://doi.org/10.5670/oceanog.2016.40.

Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey. 1997. A finite-volume, incompressible Navier-Stokes model for studies of the ocean on parallel computers. Journal of Geophysical Research 102(C3):5,753–5,766.

McPhaden, M.J. 1993. TOGA-TAO and the 1991–93 El Niño-Southern Oscillation event. Oceanography 6(2):36–44, https://doi.org/​10.5670/oceanog.1993.12.

McPhaden, M.J., G. Meyers, K. Ando, Y. Masumoto, V.S.N. Murty, M. Ravichandran, F. Syamsudin, J. Vialard, L. Yu, and W. Yu. 2009. RAMA: The Research Moored Array for African-Asian-Australian Monsoon Analysis and Prediction. Bulletin of American Meteorological Society 90:459–480, https://doi.org/10.1175/2008BAMS2608.1.

Narvekar, J., and S. Prasanna Kumar. 2006. Seasonal variability of the mixed layer in the central Bay of Bengal and associated changes in nutrients and chlorophyll. Deep Sea Research Part I 53:820–835, https://doi.org/10.1016/​j.dsr.2006.01.012.

Menemenlis, D., J.M. Campin, P. Heimbach, C. Hill, T. Lee, A. Nguyen, M. Schodlock, and H. Zhang. 2008. ECCO2: High resolution global ocean and sea ice data synthesis. Mercator Ocean Quarterly Newsletter #31:13–21, http://ecco2.org/manuscripts/reports/ECCO2_Mercator.pdf.

Packnowski, R.C., and S.G.H. Philander. 1981. Parameterization of vertical mixing in numerical models of the tropical ocean. Journal of Physical Oceanography 11:1,442–1,451, https://doi.org/10.1175/1520-0485(1981)011​<1443:POVMIN>2.0.CO;2.

Pan, H.L., and W.S. Wu. 1995. Implementing a Mass Flux Convective Parameterization Package for the NMC Medium-Range Forecast Model. NOAA National Meteorological Center Office Note 409, 40 pp.

Papa, F., C. Prigent, F. Aires, C. Jimenez, W.B. Rossow, and E. Matthews. 2010. Interannual variability of surface water extent at global scale. Journal of Geophysical Research 115, D12111, https://doi.org/10.1029/2009JD012674.

Parekh, A., J.S. Chowdary, O. Sayantani, T. Fousiya, and C. Gnanaseelan. 2016. Tropical Indian Ocean surface salinity bias in Climate Forecasting System coupled models and the role of upper ocean processes. Climate Dynamics 46:2,403–2,422, https://doi.org/10.1007/s00382-015-2709-8.

Prasad, T.G. 1997. Annual and seasonal mean buoyancy fluxes for the tropical Indian Ocean. Current Science 73:667–674.

Praveen Kumar, B., J. Vialard, M. Lengaigne, V.S.N. Murty, and M.J. McPhaden. 2010. TropFlux: Air-sea fluxes for the global tropical oceans: Description and evaluation against observations. Climate Dynamics 38:1,521–1,543, https://doi.org/10.1007/s00382-011-1115-0.

Rahaman, H., M. Ravichandran, D. Sengupta, M.J. Harrison, and S.M. Griffies. 2014. Development of a regional model for the North Indian Ocean. Ocean Modelling 75:1–19, https://doi.org/10.1016/​j.ocemod.2013.12.005.

Rao, R.R., and R. Sivakumar. 1999. On the possible mechanisms of the evolution of a mini-warm pool during the pre-summer monsoon season and the genesis of onset vortex in the southeastern Arabian Sea. Quarterly Journal of Royal Meteorological Society 125:787–809, https://doi.org/10.1002/qj.49712555503.

Rao, R.R., and R. Sivakumar. 2003. Seasonal variability of sea surface salinity and salt budget of the mixed layer of the north Indian Ocean. Journal of Geophysical Research 108(C1), 3009, https://doi.org/10.1029/2001JC000907.

Ravichandran, M., D. Behringer, S. Sivareddy, M.S. Girishkumar, N. Chacko, and R. Harikumar. 2013. Evaluation of the Global Ocean Data Assimilation System at INCOIS: The Tropical Indian Ocean. Ocean Modelling 69:123–135, https://doi.org/10.1016/j.ocemod.2013.05.003.

Roxy, M. 2014. Sensitivity of precipitation to sea surface temperature over the tropical summer monsoon region and its quantification. Climate Dynamics 43:1,159–1,169, https://doi.org/10.1007/s00382-013-1881-y.

Saha, S., S. Moorthi, X. Wu, J. Wang, S. Nadiga, P. Tripp, D. Behringer, Y.-T. Hou, H-y. Chuang, M. Iredell, and others. 2014. The NCEP Climate Forecast System Version 2. Journal of Climate 27:2,185–2,208, https://doi.org/10.1175/JCLI-D-12-00823.1.

Saha, S., and S. Nadiga, C. Thiaw, J. Wang, W. Wang, Q. Zhang, H.M. Van den Dool, H.-L. Pan, S. Moorthi, D. Behringer, and others. 2006. The NCEP Climate Forecast System. Journal of Climate 19:3,483–3,517, https://doi.org/10.1175/JCLI3812.1.

Sahai, A.K., S. Sharmila, S. Abhilash, R. Chattopadhyay, N. Borah, R.P.M. Krishna, J. Susmitha, M. Roxy, S. De, and S. Pattnaik. 2013. Simulation and extended range prediction of monsoon intraseasonal oscillations in NCEP CFS/GFS version 2 framework. Current Science 104:1,394–1,408.

Sanilkumar, K., N. Mohankumar, M. Joseph, and R. Rao. 1994. Genesis of meteorological disturbances and thermohaline variability of the upper layers in the head of the Bay of Bengal during Monsoon Trough Boundary Layer Experiment (MONTBLEX-90). Deep Sea Research Part I 41:1,569–1,581, https://doi.org/​10.1016/0967-0637(94)90061-2

Sarkar, S., H.T. Pham, S. Ramachandran, J.D. Nash, A. Tandon, J. Buckley, A.A. Lotliker, and M.M. Omand. 2016. The interplay between submesoscale instabilities and turbulence in the surface layer of the Bay of Bengal. Oceanography 29(2):146–157, https://doi.org/10.5670/oceanog.2016.47.

Schott, F., and J.P. McCreary. 2001. The monsoon circulation of the Indian Ocean. Progress in Oceanography 51:1–123, https://doi.org/10.1016/S0079-6611(01)00083-0.

Sengupta, D., G.N. Bharath Raj, M. Ravichandran, J. Sree Lekha, and F. Papa. 2016. Near-surface salinity and stratification in the north Bay of Bengal from moored observations. Geophysical Research Letters 43:4,448–4,456, https://doi.org/10.1002/2016GL068339.

Sengupta, D., G.N. Bharath Raj, and S.S.C. Shenoi. 2006. Surface freshwater from Bay of Bengal runoff and Indonesian throughflow in the tropical Indian Ocean. Geophysical Research Letters 33, L22609, https://doi.org/10.1029/2006GL027573.

Servain, J., A. Busalacchi, M.J. McPhaden, A.D. Moura, G. Reverdin, M. Vianna, and S. Zebiak. 1998. A Pilot Research Moored Array in the Tropical Atlantic (PIRATA). Bulletin of the American Meteorology Society 79:2,019–2,031, https://doi.org/10.1175/1520-0477(1998)079<2019:APRMAI>2.0.CO;2.

Seo, H., S.P. Xie, R. Murtugudde, M. Jochum, and A.J. Miller. 2009. Seasonal effects of Indian Ocean freshwater forcing in a regional coupled model. Journal of Climate 22:6,577–6,596, https://doi.org/10.1175/2009JCLI2990.1.

Shankar, D., P.N. Vinayachandran, and A.S. Unnikrishnan. 2002. The monsoon currents in the north Indian Ocean. Progress in Oceanography 52:63–120, https://doi.org/10.1016/S0079-6611(02)00024-1.

Shenoi, S.S.C., D. Shankar, and S.R. Shetye. 2002. Differences in heat budgets of the near surface Arabian Sea and Bay of Bengal: Implications for the summer monsoon. Journal of Geophysical Research 107, 3052, https://doi.org/10.1029/2000JC000679.

Subramanian, V. 1993. Sediment load of Indian rivers. Current Science 64:928–930.

Thompson, B., C. Gnanaseelan, and P.S. Salvekar. 2006. Variability in the Indian Ocean circulation and salinity and its impact on SST anomalies during dipole events. Journal of Marine Research 64:853–880, https://doi.org/​10.1357/002224006779698350.

Venkatesan, R., V.R. Shamji, G. Latha, S. Mathew, R.R. Rao, A. Muthiah, and M.A. Atmanand. 2013. In situ ocean subsurface time-series measurements from OMNI buoy network in the Bay of Bengal. Current Science 104(9):1,166–1,177.

Vinayachandran, P.N., J.P. McCreary, R.R. Hood, and K.E. Kohler. 2005. A numerical investigation of the phytoplankton bloom in the Bay of Bengal during northeast monsoon. Journal of Geophysical Research 110, C12001, https://doi.org/10.1029/2005JC002966.

Vinayachandran, P.N., and R.S. Nanjundiah. 2009. Indian Ocean sea surface salinity variations in a coupled model. Climate Dynamics 33:245–263, https://doi.org/10.1007/s00382-008-0511-6.

Vinayachandran, P.N., D. Shankar, S. Vernekar, K.K. Sandeep, P. Amol, C.P. Neema, and A. Chatterjee. 2013. A summer monsoon pump to keep the Bay of Bengal salty. Geophysical Research Letters 40:1,777–1,782, https://doi.org/​10.1002/grl.50274.

Wijesekera, H.W., E. Shroyer, A. Tandon, M. Ravichandran, D. Sengupta, S.U.P. Jinadasa, H.J.S. Fernando, N. Agrawal, K. Arulanathan, G.S. Bhat, and others. In press. ASIRI: An Ocean-Atmosphere Initiative for Bay of Bengal. Bulletin of the American Meteorological Society, https://doi.org/10.1175/BAMS-D-14-00197.1.

Wilson, E.A., and S.C. Riser. 2016. An assessment of the seasonal salinity budget for the upper Bay of Bengal. Journal of Physical Oceanography 46(5):1,361–1,376, https://doi.org/10.1175/JPO-D-15-0147.1.

Zweng, M.M, J.R. Reagan, J.I. Antonov, R.A. Locarnini, A.V. Mishonov, T.P. Boyer, H.E. Garcia, O.K. Baranova, D.R. Johnson, D. Seidov, and M.M. Biddle. 2013. World Ocean Atlas 2013, Volume 2: Salinity. S. Levitus, ed., A. Mishonov, technical ed., NOAA Atlas NESDIS 74, 39 pp.