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

View Issue TOC
Volume 29, No. 2
Pages 18 - 27

OpenAccess

Monsoons to Mixing in the Bay of Bengal: Multiscale Air-Sea Interactions and Monsoon Predictability

By B.N. Goswami , Suryachandra A. Rao, Debasis Sengupta, and Soumi Chakravorty 
Jump to
Article Abstract Citation References Copyright & Usage
Article Abstract

Skillful prediction of the “active” and “break” spells of monsoon intraseasonal oscillations during the South Asian monsoon season is crucial for the socio-economic fate of one-sixth of the world’s population, yet it remains a grand challenge problem. The limited skill of our coupled weather and climate models is largely due to our inability to represent the complex multiscale interactions of the north Indian Ocean and the atmosphere. Air-sea interactions are at the heart of not only the climatological mean annual cycle of the South Asian monsoon but also its synoptic, subseasonal, interannual, and decadal variability. With high local monsoon precipitation and discharge from major rivers (Ganges-Brahmaputra, Irrawaddy), the Bay of Bengal (BoB) exhibits the lowest surface salinities in the tropics as well as unique thermal stratification, making it a natural laboratory for studying multiscale interactions ranging from planetary-scale monsoons to submesoscale mixing in freshwater pools. The current ocean component of coupled models is inadequate for simulating the BoB’s upper-ocean thermal structure with fidelity. To further improve monsoon forecasts on intraseasonal and interannual time scales, we need new high-resolution and high-frequency observations over the BoB to fill the gap in our understanding of how the ocean mixes in highly fresh regions, and we need modeling of processes that will convert this understanding to parameterizations of mixing that can be used to improve large-scale ocean models.

Citation

Goswami, B.N., S.A. Rao, D. Sengupta, and S. Chakravorty. 2016. Monsoons to mixing in the Bay of Bengal: Multiscale air-sea interactions and monsoon predictability. Oceanography 29(2):18–27, https://doi.org/10.5670/oceanog.2016.35.

References
    Abhilash, S., A.K. Sahai, N. Borah, R. Chattopadhyay, S. Joseph, S. Sharmila, S. De, B.N. Goswami, and A. Kumar. 2014a. Prediction and monitoring of monsoon intraseasonal oscillations over Indian monsoon region in an ensemble prediction system using CFSv2. Climate Dynamics 42:2,801–2,815, https://doi.org/10.1007/s00382-013-2045-9.
  1. Abhilash, S., A.K. Sahai, N. Borah, R. Chattopadhyay, S. Joseph, S. Sharmila, S. De, and B.N. Goswami. 2013. Does bias correction in the forecasted SST improve the extended range prediction skill of active-break spells of Indian summer monsoon rainfall? Atmospheric Science Letters 15:114–119, https://doi.org/10.1002/asl2.477.
  2. Abhilash, S., A.K. Sahai, S. Pattnaik, B.N. Goswami, and A. Kumar. 2014b. Extended range prediction of active-break spells of Indian summer monsoon rainfall using an ensemble prediction system in NCEP Climate Forecast System. International Journal of Climatology 34:98–113, https://doi.org/10.1002/joc.3668.
  3. Balaguru, K., P. Chang, R. Saravanan, L.R. Leung, Z. Xu, M. Li, and J.S. Hsieh. 2012. Ocean barrier layers’ effect on tropical cyclone intensification. Proceedings of the National Academy of Sciences of the United States of America 109(36):14,343–14,347, https://doi.org/​10.1073/pnas.1201364109.
  4. Balaguru, K., S. Taraphdar, L.R. Leung, and G.R. Foltz. 2014. Increase in the intensity of postmonsoon Bay of Bengal tropical cyclones. Geophysical Research Letters 41(10):3,594–3,601, https://doi.org/10.1002/2014GL060197.
  5. Bhat, G.S., S. Gadgil, P.V. Hareesh Kumar, S.R. Kalsi, P. Madhusoodanan, V.S.N. Murty, C.V.K. Prasada Rao, V. Ramesh Babu, L.V.G. Rao, R.R. Rao, and others. 2001. BOBMEX: The Bay of Bengal monsoon experiment. Bulletin of the American Meteorological Society 82:2,217–2,243, https://doi.org/10.1175/1520-0477(2001)082​<2217:BTBOBM>2.3.CO;2.
  6. Carton, J.A., and B.S. Giese. 2008. A reanalysis of ocean climate using simple ocean data assimilation (SODA). Monthly Weather Review 136:2,999–3,017, https://doi.org/10.1175/2007MWR1978.1.
  7. Chatterjee, P., and B.N. Goswami. 2004. Structure, genesis and scale selection of the tropical quasi-​biweekly mode. Quarterly Journal of the Royal Meteorological Society 130:1,171–1,194, https://doi.org/10.1256/qj.03.133.
  8. Gadgil, S., and S. Gadgil. 2006. The Indian monsoon, GDP and agriculture. Economic and Political Weekly 41(47):4,887–4,895.
  9. George, G., D.N. Rao, C.T. Sabeerali, A. Srivastava, and S.A. Rao. 2016. Indian summer monsoon prediction and simulation in CFSv2 coupled model. Atmospheric Science Letters 17:57–64, https://doi.org/10.1002/asl.599.
  10. Goswami, B.N. 1998. Interannual variations of Indian summer monsoon in a GCM: External conditions versus internal feedbacks. Journal of Climate 11:501–522.
  11. Goswami, B.N. 2012. South Asian monsoon. Chapter 2 in Intraseasonal Variability in the Atmosphere-Ocean Climate System, 2nd ed. W.K.M. Lau and D. Waliser, eds, Springer-Praxis, Chichester, UK.
  12. Goswami, B.N., R.S. Ajayamohan, P.K. Xavier, and D. Sengupta. 2003. Clustering of synoptic activity during the Indian summer monsoon intraseasonal oscillations. Geophysical Research Letters 30, 1431, https://doi.org/10.1029/2002GL016734.
  13. Goswami, B.N., G. Wu, and T. Yasunari. 2006. The annual cycle, intraseasonal oscillations, and roadblock to seasonal predictability of the Asian summer monsoon. Journal of Climate 19:5,078–5,099, https://doi.org/10.1175/JCLI3901.1.
  14. Goswami, B.N., and P.K. Xavier. 2003. Potential predictability and extended range prediction of Indian summer monsoon breaks. Geophysical Research Letters 30, 1966, https://doi.org/​10.1029/2003GL017810.
  15. Goswami, B.N., and P.K. Xavier. 2005. Dynamics of “internal” interannual variability of the Indian summer monsoon in a GCM. Journal of Geophysical Research 110, D24104, https://doi.org/10.1029/2005JD006042.
  16. Hazra, A., H.S. Chaudhari, S.A. Rao, B.N. Goswami, A. Dhakate, S. Pokhrel, and S.K. Saha. 2015. Impact of revised cloud microphysical scheme in CFSv2 on the simulation of the India summer monsoon. International Journal of Climatology 5:4,738–4,755, https://doi.org/10.1002/joc.4320.
  17. Joseph, S., A.K. Sahai, R. Chattopadhyay, and B.N. Goswami. 2011. Can El Niño-Southern Oscillation (ENSO) events modulate intraseasonal oscillations of Indian summer monsoon? Journal of Geophysical Research 116, D20123, https://doi.org/10.1029/2010JD015510.
  18. Krishna Kumar, K., M. Hoerling, and B. Rajagopalan. 2005. Advancing dynamical prediction of Indian monsoon rainfall. Geophysical Research Letters 32, L08704, https://doi.org/10.1029/2004GL021979.
  19. Large, W.G., J.C. McWilliams, and S.C. Doney. 1994. Oceanic vertical mixing: A review and a model with nonlocal boundary layer parameterizations. Reviews of Geophysics 32(4):363–403, https://doi.org/10.1029/94RG01872.
  20. Lindzen, R., and S. Nigam. 1987. On the role of sea surface temperature gradients in forcing low-level winds and convergence in the tropics. Journal of the Atmospheric Sciences 44:2,418–2,436, https://doi.org/10.1175/​1520-​0469(1987)044<2418:OTROSS>2.0.CO;2.
  21. Llicak, M., A.J. Adcroft, S.M. Griffies, and R.W. Hallberg. 2012. Spurious dianeutral mixing and role of momentum closure. Ocean Modeling 45–46:37–58, https://doi.org/10.1016/​j.ocemod.2011.10.003.
  22. Loschnigg, J., G.A. Meehl, P.J. Webster, J.M. Arblaster, and G.A. Compo. 2003. The Asian monsoon, the tropospheric biennial oscillation and the Indian Ocean zonal mode in the NCAR GCM. Journal of Climate 16:1,617–1,642, https://doi.org/10.1175/1520-0442(2003)016​<1617:TAMTTB>2.0.CO;2.
  23. Loschnigg, J., and P.J. Webster. 2000. A coupled ocean-atmosphere system of SST regulation of the Indian monsoon. Journal of Climate 13:3,342–3,360, https://doi.org/10.1175/​1520-0442(2000)013​<3342:ACOASO>2.0.CO;2.
  24. Molnar, P., R.W. Boos, and D.S. Battisti. 2010. Orographic controls on climate and paleoclimate of Asia: Thermal and mechanical roles for the Tibetan Plateau. Annual Review of Earth and Planetary Sciences 38:77–102, https://doi.org/10.1146/annurev-earth-040809-152456.
  25. Möbis, B., and B. Stevens. 2012. Factors controlling the position of the Intertropical Convergence Zone on an aquaplanet. Journal of Advances in Modeling Earth Systems 4, M00A04, https://doi.org/10.1029/2012MS000199.
  26. Mujumdar, M., K. Salunke, S.A. Rao, M. Ravichandran, and B.N. Goswami. 2011. Diurnal cycle induced amplification of sea surface temperature intraseasonal oscillations over the Bay of Bengal in summer monsoon season. IEEE Geoscience and Remote Sensing Letters 29:206–210, https://doi.org/10.1109/LGRS.2010.2060183
  27. Narapusetty, B., R. Murtugudde, H. Wang, and A. Kumar. 2015. Ocean-atmosphere processes driving Indian summer monsoon biases in CFSv2 hindcasts. Climate Dynamics, https://doi.org/10.1007/s00382-015-2910-9.
  28. Pokhrel, S., S.K. Saha, A.R. Dhakate, R. Hasibur, H.S. Chaudhari, K. Salunke, A. Hazra, K. Sujith, and D.R. Sikka. 2015. Seasonal prediction of Indian summer monsoon rainfall in NCEP CFSv2: Forecast and predictability error. Climate Dynamics 46(7):2,305–2,326, https://doi.org/​10.1007/s00382-015-2703-1.
  29. Ramu, D.A., C.T. Sabeerali, R. Chattopadhyay, D.N. Rao, G. George, A.R. Dhakate, K. Salunke, A. Srivastava, and S.A. Rao. 2016. Indian summer monsoon rainfall simulation and prediction skill in the CFSv2 coupled model: Impact of atmospheric horizontal resolution. Journal of Geophysical Research 121:2,205–2,221, https://doi.org/10.1002/2015JD024629.
  30. Rajeevan, M., C.K. Unnikrishnan, and B. Preethi. 2012. Evaluation of the ENSEMBLES multi-model seasonal forecasts of Indian summer monsoon variability. Climate Dynamics 38:2,257–2,274, https://doi.org/10.1007/s00382-011-1061-x.
  31. Sabeerali, C.T., D.A. Ramu, A.R. Dhakate, K. Salunke, S. Mahapatra, and S.A. Rao. 2013. Simulation of boreal summer intraseasonal oscillations in the latest CMIP5 coupled GCMs. Journal of Geophysical Research 118:4,401–4,420, https://doi.org/10.1002/jgrd.50403.
  32. Schott, F.A., M. Dengler, and R. Schoenefeldt. 2002. The shallow overturning circulation of the Indian Ocean. Progress in Oceanography 53:57–103, https://doi.org/10.1016/S0079-6611(02)00039-3.
  33. Sengupta, D., B.R. Goddalehundi, and D.S. Anitha. 2008. Cyclone-induced mixing does not cool SST in the post-monsoon north Bay of Bengal. Atmospheric Science Letters 9:1–6, https://doi.org/10.1002/asl.162.
  34. Sengupta, D., B.N. Goswami, and R. Senan. 2001. Coherent intraseasonal oscillations of ocean and atmosphere during the Asian summer monsoon. Geophysical Research Letters 28(21):4,127–4,130, https://doi.org/10.1029/2001GL013587.
  35. Sengupta, D., and M. Ravichandran. 2001. Oscillations of Bay of Bengal sea surface temperature during the 1998 summer monsoon. Geophysical Research Letters 28(10):2,033–2,036, https://doi.org/​10.1029/2000GL012548.
  36. Sengupta, D., R. Senan, V.S.N. Murty, and V. Fernando. 2004. A biweekly mode in the equatorial Indian Ocean. Journal of Geophysical Research 109, C10003, https://doi.org/10.1029/​2004JC002329.
  37. Sharmila, S., P.A. Pillai, S. Joseph, M. Roxy, R.P.M. Krishna, R. Chattopadhyay, S. Abhilash, A.K. Sahai, and B.N. Goswami. 2013. Role of ocean-atmosphere interaction on northward propagation of Indian summer monsoon intra-seasonal oscillations (MISO). Climate Dynamics 41:1,651–1,669, https://doi.org/10.1007/s00382-013-1854-1.
  38. Singh, N., M. Lengaigne, E.M. Vincent, J. Vialard, G. Madec, G. Samson, M.R. Ramesh Kumar, and F. Durand. 2012. Influence of upper-ocean stratification on tropical cyclone-induced surface cooling in the Bay of Bengal. Journal of Geophysical Research 117, C12020, https://doi.org/10.1029/2012JC008433.
  39. Suhas, E., J.M. Neena, and B.N. Goswami. 2013. An Indian monsoon intraseasonal oscillations (MISO) index for real time monitoring and forecast verification. Climate Dynamics 40:2,605–2,616, https://doi.org/10.1007/s00382-012-1462-5.
  40. Uppala, S.M., P.W. Kallberg, A.J. Simmons, U. Andrae, V. Da Costa Bechtold, M. Florino, J.K. Gibson, J. Haseler, A. Hernandez, G.A. Kelly, and others. (2005). The ERA-40 re-analysis. Quarterly Journal of the Royal Meteorological Society 131:2,961–3,012, https://doi.org/10.1256/qj.04.176.
  41. Webster, P.J., V.O. Magana, T.N. Palmer, J. Shukla, R.T. Tomas, M. Yanai, and T. Yasunari. 1998. Monsoons: Processes, predictability and the prospects of prediction. Journal of Geophysical Research 103(C7):14,451–14,510, https://doi.org/10.1029/97JC02719.
  42. Xavier, P.K., and B.N. Goswami. 2007. A promising alternative to seasonal mean all India rainfall. Current Science 93(2):193–202.
  43. Xie, S.P., H. Xu, N.H. Saji, Y. Wang, and W.T. Liu. 2006. Role of narrow mountains in large-scale organization of Asian monsoon convection. Journal of Climate 19:3,420–3,429, https://doi.org/10.1175/JCLI3777.1.
Copyright & Usage

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.