Recent observations of surface meteorology and exchanges of heat, freshwater, and momentum between the ocean and the atmosphere in the Bay of Bengal are presented. These observations characterize air-sea interaction at 18°N, 89.5°E from December 2014 to January 2016 and also at other locations in the northern Bay of Bengal. Monsoonal variability dominated the records, with winds to the northeast in summer and to the southwest in winter. This variability included a strong annual cycle in the atmospheric forcing of the ocean in the Bay of Bengal, with the winter monsoon marked by sustained ocean heat loss resulting in ocean cooling, and the summer monsoon marked by strong storm events with dark skies and rain that also resulted in ocean cooling. The spring intermonsoon was a period of clear skies and low winds, when strong solar heating and weak wind-driven mixing led to ocean warming. The fall intermonsoon was a transitional period, with some storm events but also with enough clear skies and sunlight that ocean surface temperature rose again. Mooring and shipboard observations are used to examine the ability of model-based surface fluxes to represent air-sea interaction in the Bay of Bengal; the model-based fluxes have significant errors. The surface forcing observed at 18°N is also used together with a one-dimensional ocean model to illustrate the potential for local air-sea interaction to drive upper-ocean variability in the Bay of Bengal.

Weller, R.A., J.T. Farrar, J. Buckley, S. Mathew, R. Venkatesan, J. Sree Lekha, D. Chaudhuri, N. Suresh Kumar, and B. Praveen Kumar. 2016. Air-sea interaction in the Bay of Bengal. Oceanography 29(2):28–37, https://doi.org/10.5670/oceanog.2016.36.

Agarwal, N., R. Sharma, S. Basu, A. Parekh, A. Sarkar, and V.K. Agarwal. 2007. Bay of Bengal summer monsoon 10–20 day variability in sea surface temperature using model and observations. Geophysical. Research Letters 34, L06602, https://doi.org/10.1029/2007GL029296.

Bhat, G.S. 2002. Near-surface variations and surface fluxes over the northern Bay of Bengal during the 1999 Indian summer monsoon. Journal of Geophysical Research 107(D17), 4336, https://doi.org/​10.1029/2001JD000382.

Bigorre, S.P., R.A. Weller, J.B. Edson, and J.D. Ware. 2013. A surface mooring for air–sea interaction research in the Gulf Stream: Part II. Analysis of the observations and their accuracies. Journal of Atmospheric and Oceanic Technology 30:450–469, https://doi.org/10.1175/JTECH-D-12-00078.1.

Brunke, M.A., Z. Wang, X. Zeng, M. Bosilovich, and C.-L. Shie. 2011. An assessment of the uncertainties in ocean surface turbulent fluxes in 11 reanalysis, satellite-derived, and combined global datasets. Journal of Climate 24:5,469–5,493, https://doi.org/10.1175/2011JCLI4223.1.

Colbo, K., and R.A. Weller. 2009. Accuracy of the IMET sensor package in the subtropics. Journal of Atmospheric and Oceanic Technology 26(9):1,867–1,890, https://doi.org/​10.1175/2009JTECHO667.1.

Decker, M., M.A. Brunke, Z. Wang, K. Sakaguchi, X. Zeng, and M.G. Bosilovich. 2012. Evaluation of the reanalysis products from GSFC, NCEP, and ECMWF using flux tower observations. Journal of Climate 25:1,916–1,944, https://doi.org/10.1175/JCLI-D-11-00004.1.

European Centre for Medium-Range Weather Forecasts. 2012. ERA-Interim Project, Single Parameter 6-Hourly Surface Analysis and Surface Forecast Time Series (updated monthly). Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory, https://doi.org/10.5065/D64747WN.

Fairall, C.W., E.F. Bradley, J.E. Hare, A.A. Grachev, and J.B. Edson. 2003. Bulk paramterization of air-sea fluxes: Updates and verification for the COARE algorithm. Journal of Climate 16:571–591, https://doi.org/10.1175/1520-0442(2003)016​<0571:BPOASF>2.0.CO;2. 

Global Modeling and Assimilation Office. 2008. MERRA, version 5.2.0. Goddard Space Flight Center Distributed Active Archive Center, Greenbelt, MD, USA, https://doi.org/10.5067/4EQ54AKI405R.

Global Modeling and Assimilation Office. 2015. MERRA-2, version 5.12.4. Goddard Space Flight Center Distributed Active Archive Center, Greenbelt, MD, USA, https://doi.org/10.5067/H0VVAD8F6MX5.

Hosom, D.S., R.A. Weller, R.E. Payne, and K.E. Prada. 1995. The IMET (improved meteorology) ship and buoy systems. Journal of Atmospheric and Oceanic Technology 12:527–540, https://doi.org/10.1175/1520-0426(1995)012​<0527:TIMSAB>2.0.CO;2. 

Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin, M. Iredell, S. Saha, G. White, J. Woollen, and others. 1996. The NCEP/NCAR 40-Year Reanalysis Project. Bulletin of the American Meteorological Society 77:437–471, https://doi.org/10.1175/1520-0477(1996)077​<0437:TNYRP>2.0.CO;2.

Kumar, M.R. Ramesh, and T.G. Prasad. 1997. Annual and interannual variation of precipitation over the tropical Indian Ocean. Journal of Geophysical Research 108(C8):18,519–18,527, https://doi.org/10.1029/97JC00979.

Lucas, A.J., E.L. Shroyer, H.W. Wijesekera, H.J.S. Fernando, E. D’Asaro, M. Ravichandran, S.U.P. Jinadasa, J.A. MacKinnon, J.D. Nash, R. Sharma, and others. 2014. Mixing to monsoons: Air-sea interactions in the Bay of Bengal. Eos, Transactions American Geophysical Union 95(30):269, https://doi.org/​10.1002/2014EO300001.

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 the American Meteorological Society 90:459–480, https://doi.org/10.1175/2008BAMS2608.1.

Paulson, C.A., and J.J. Simpson. 1977. Irradiance measurements in the upper ocean. Journal of Physical Oceanography 7:952–956, https://doi.org/10.1175/​1520-0485(1977)007<0952:IMITUO>2.0.CO;2.

Prasad, T.G. 2004. A comparison of mixed-layer dynamics between the Arabian Sea and Bay of Bengal: One-dimensional model results. Journal of Geophysical Research 109, C03035, https://doi.org/10.1029/2003JC002000.

Price, J.F., R.A. Weller, and R. Pinkel. 1986. Diurnal cycling: Observations and models of upper ocean response to diurnal heating, cooling, and wind mixing. Journal of Geophysical Research 91(C7):8,411–8,427, https://doi.org/​10.1029/JC091iC07p08411.

Rao, S.A., S.K. Saha, S. Pokhrel, D. Sundar, A.R. Dhakate, S. Mahapatra, S. Ali, H.S. Chaudhari, P. Shreeram, S. Vasimalla, and others. 2011. Modulation of SST, SSS over northern Bay of Bengal on ISO time scale. Journal of Geophysical Research 116, C09026, https://doi.org/​10.1029/2010JC006804.

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.

Shankar, D., S.R. Shetye, and P.V. Joseph. 2007. Link between convection and meridional gradient of sea surface temperature in the Bay of Bengal. Journal of Earth System Science 116(5):385–406, https://doi.org/10.1007/s12040-007-0038-y. 

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(C6), https://doi.org/​10.1029/2000JC000679.

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 from OMNI buoy network in the Bay of Bengal. Current Science 104(9):1,166–1,177, http://www.currentscience.ac.in/Volumes/104/09/1166.pdf.

Vinayachandran, P.N., V.S.N. Murty, and V. Ramesh Babu. 2002. Observations of barrier layer formation in the Bay of Bengal during summer monsoon. Journal of Geophysical Research 107(C12), 8018, https://doi.org/10.1029/2001JC000831.

Weller, R.A., A.S. Fischer, D. Rudnick, C. Eriksen, T. Dickey, J. Marra, C. Fox, and R. Leben. 2002. Moored observations of upper-ocean response to the monsoons in the Arabian Sea during 1994–1995. Deep Sea Research Part II 49:2,195–2,230, https://doi.org/10.1016/s0967-0645(02)00035-8.

Weller, R.A., S.P. Bigorre, J. Lord, J.D. Ware, and J.B. Edson. 2012. A surface mooring for air-sea interaction research in the Gulf Stream: Part 1. Mooring design and instrumentation. Journal of Atmospheric and Oceanic Technology 29:1,363–1,376, https://doi.org/​10.1175/JTECH-D-12-00060.1.

Wijesekera, H.W., E. Shroyer, A. Tandon, M. Ravichandran, D. Sengupta, P. Jinadas, 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.

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