Indian Ocean and monsoon coupled interactions in a warming environment

Swapna, Panickal; Krishnan, R.; Wallace, J.
May 2014
Climate Dynamics;May2014, Vol. 42 Issue 9/10, p2439
Academic Journal
Several studies have drawn attention to the steady warming of the equatorial and tropical Indian Ocean (IO) sea surface temperature (SST) observed during recent decades. An intriguing aspect of the IO SST warming trend is that it is has been accompanied by a pronounced weakening of the large-scale boreal summer monsoon circulation. Based on a detailed diagnostic analysis of observed datasets, reanalysis products and IPCC AR4 coupled model output, this study examines how the observed changes in the summer monsoon circulation could have contributed to this SST warming trend. The present results reveal that the weakening trend of the summer monsoon cross-equatorial flow has favored a reorientation of surface westerlies towards the equatorial IO during recent decades, relative to summer monsoons of earlier decades, which were dominated by stronger cross-equatorial flow. Our analysis suggests that the weakening of the summer monsoon cross-equatorial flow has in turn significantly accelerated the SST warming in the central equatorial IO. While the trend in the equatorial westerlies has promoted downwelling and thermocline deepening in the eastern equatorial IO, the central equatorial IO warming is attributed to reduced upwelling in response to a weakening trend of the wind-stress curl. The observed trends in Indian monsoon rainfall and the near-equatorial SST warming are shown to be closely related to variations in the meridional gradient of the monsoon zonal winds. An examination of the twentieth century simulations from 22 IPCC AR4 models, suggests that some models capture the recent equatorial IO warming associated with the weakened summer monsoon circulation reasonably well. The individual member models, however, exhibit significant inter-model variations in representing the observed response of the IO and monsoon coupled system.


Related Articles

  • The CCSM4 Ocean Component. Danabasoglu, Gokhan; Bates, Susan C.; Briegleb, Bruce P.; Jayne, Steven R.; Jochum, Markus; Large, William G.; Peacock, Synte; Yeager, Steve G. // Journal of Climate;Mar2012, Vol. 25 Issue 5, p1361 

    The ocean component of the Community Climate System Model version 4 (CCSM4) is described, and its solutions from the twentieth-century (20C) simulations are documented in comparison with observations and those of CCSM3. The improvements to the ocean model physical processes include new...

  • Epochal changes in the seasonal evolution of tropical Indian Ocean warming associated with El Niño. Chakravorty, Soumi; Chowdary, J.; Gnanaseelan, C. // Climate Dynamics;Feb2014, Vol. 42 Issue 3/4, p805 

    The epochal changes in the seasonal evolution of El Niño induced tropical Indian Ocean (TIO) warming in the context of mid-1970s regime shift is investigated in this study. El Niño induced warming is delayed by one season in the northern TIO during epoch-2 (post mid-1970) and southern TIO...

  • How does ocean ventilation change under global warming? Gnanadesikan, A.; Russell, J. L.; Zeng, F. // Ocean Science Discussions;2006, Vol. 3 Issue 4, p805 

    Since the upper ocean takes up much of the heat added to the earth system by anthropogenic global warming, one would expect that global warming would lead to an increase in stratification and a decrease in the ventilation of the ocean interior. However, multiple simulations in global coupled...

  • Heat and Mass Budgets of the Warm Upper Layer of the Tropical Atlantic Ocean in 1979–99. Vauclair, F.; Du Penhoat, Y.; Reverdin, G. // Journal of Physical Oceanography;Apr2004, Vol. 34 Issue 4, p903 

    The mass and heat budgets of the warm upper-ocean layer are investigated in the equatorial Atlantic using in situ observations during the period 1979–99, which encompassed a series of warm events in the equatorial Atlantic. The warm water layer is defined as the layer having an in situ...

  • Simulations of two types of El Niño events by an optimal forcing vector approach. Duan, Wansuo; Tian, Ben; Xu, Hui // Climate Dynamics;Sep2014, Vol. 43 Issue 5/6, p1677 

    In this paper, an optimal forcing vector (OFV) approach is proposed. The OFV offsets tendency errors and optimizes the agreement of the model simulation with observation. We apply the OFV approach to the well-known Zebiak-Cane model and simulate several observed eastern Pacific (EP) El Niño...

  • Evaluation of global ocean-sea-ice model simulations based on the experimental protocols of the Ocean Model Intercomparison Project phase 2 (OMIP-2). Tsujino, Hiroyuki; Urakawa, L. Shogo; Griffies, Stephen M.; Danabasoglu, Gokhan; Adcroft, Alistair J.; Amaral, Arthur E.; Arsouze, Thomas; Bentsen, Mats; Bernardello, Raffaele; Böning, Claus W.; Bozec, Alexandra; Chassignet, Eric P.; Danilov, Sergey; Dussin, Raphael; Exarchou, Eleftheria; Fogli, Pier Giuseppe; Fox-Kemper, Baylor; Guo, Chuncheng; Ilicak, Mehmet; Iovino, Doroteaciro // Geoscientific Model Development Discussions;2020, p1 

    We present a new framework for global ocean-sea-ice model simulations based on phase 2 of the Ocean Model Intercomparison Project (OMIP-2), making use of the JRA55-do atmospheric dataset. We motivate the use of OMIP-2 over the framework for the first phase of OMIP (OMIP-1), previously referred...

  • Indian Ocean Dipole Response to Global Warming in the CMIP5 Multimodel Ensemble*. Zheng, Xiao-Tong; Xie, Shang-Ping; Du, Yan; Liu, Lin; Huang, Gang; Liu, Qinyu // Journal of Climate;Aug2013, Vol. 26 Issue 16, p6067 

    The response of the Indian Ocean dipole (IOD) mode to global warming is investigated based on simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5). In response to increased greenhouse gases, an IOD-like warming pattern appears in the equatorial Indian Ocean, with reduced...

  • Influence of tropical cyclones on sea surface temperature seasonal cycle and ocean heat transport. Vincent, Emmanuel; Madec, Gurvan; Lengaigne, Matthieu; Vialard, Jérôme; Koch-Larrouy, Ariane // Climate Dynamics;Oct2013, Vol. 41 Issue 7/8, p2019 

    Recent studies suggested that tropical cyclones (TCs) contribute significantly to the meridional oceanic heat transport by injecting heat into the subsurface through mixing. Here, we estimate the long-term oceanic impact of TCs by inserting realistic wind vortices along observed TCs tracks in a...

  • Fast and Slow Responses to Global Warming: Sea Surface Temperature and Precipitation Patterns. Long, Shang-Min; Xie, Shang-Ping; Zheng, Xiao-Tong; Liu, Qinyu // Journal of Climate;Jan2014, Vol. 27 Issue 1, p285 

    The time-dependent response of sea surface temperature (SST) to global warming and the associated atmospheric changes are investigated based on a 1% yr−1 CO2 increase to the quadrupling experiment of the Geophysical Fluid Dynamics Laboratory Climate Model, version 2.1. The SST response...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics