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IAPSO

JPM04 - Indian Ocean Sciences

Future Indian Ocean Warming

1. Sahil  Sharma*, Center for Climate Physics,Institute of Basic Science,Busan,South Korea

2. Kyung-Ja  Ha, Center for Climate Physics,Institute of Basic Science,Busan,South Korea

3. Ryohei  Yamaguchi, Japan Agency for Marine-Earth Science and Technology,Yokosuka,Japan

4. Keith   Rodgers, Center for Climate Physics,Institute of Basic Science,Busan,South Korea

5. Axel   Timmermann, Center for Climate Physics,Institute of Basic Science,Busan,South Korea

6. Eui-Seok  Chung, Division of Atmospheric Sciences,Korea Polar Research Institute,Incheon,South Korea

*Presenting Author

Most future projections conducted with coupled general circulation models simulate a non-uniform Indian Ocean warming, with warming hotspots occurring in the Arabian Sea (AS) and the southeastern Indian Ocean (SEIO). But little is known about the underlying physical drivers. Here, we are using a suite of large ensemble simulations of the Community Earth System Model 2 to elucidate the causes of non-uniform Indian Ocean warming. Strong negative air-sea interactions in the Eastern Indian Ocean are responsible for a future weakening of the zonal sea surface temperature gradient, resulting in a slowdown of the Indian Ocean Walker circulation and the generation of southeasterly wind anomalies over the AS. These contribute to anomalous northward ocean heat transport, reduced evaporative cooling, a weakening in upper ocean vertical mixing and an enhanced AS future warming. In contrast, the projected warming in the SEIO is related to a reduction of low-cloud cover and an associated increase in shortwave radiation. Therefore, the regional character of air-sea interactions plays a key role in promoting future large-scale tropical atmospheric circulation anomalies with implications for society and ecosystems far outside the Indian Ocean realm.