Role of atmospheric adjustments in the tropical Indian Ocean warming during the 20th century in climate models

• Published in: Geophysical research letters Vol. 35; no. 8; pp. L08712 - n/a
• Main Authors: Du, Yan, Xie, Shang-Ping
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01-04-2008; Blackwell Publishing Ltd
• Subjects: Atmosphere; atmospheric adjustments; Atmospheric Processes; Earth sciences; Earth, ocean, space; Exact sciences and technology; Global Change; Global climate models; Ocean/atmosphere interactions; Oceans; Regional climate change; SST warming; tropical Indian Ocean; Indian Ocean; ISW, Tropical Indian Ocean; SST warming; atmospheric adjustments; tropical Indian Ocean; trend-surface analysis; Long wave; simulation; solar radiation; Climate models; damping; clouds; Sea surface temperature; variability; greenhouse gas; depth; Feedback; water vapor; winds; warming; equilibrium; heat flux; evaporation; uncertainties; heat transfer
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2008GL033631

The tropical Indian Ocean has been warming steadily since 1950s, a trend simulated by a large ensemble of climate models. In models, changes in net surface heat flux are small and the warming is trapped in the top 125 m depth. Analysis of the model output suggests the following quasi‐equilibrium adjustments among various surface heat flux components. The warming is triggered by the greenhouse gas‐induced increase in downward longwave radiation, amplified by the water vapor feedback and atmospheric adjustments such as weakened winds that act to suppress turbulent heat flux from the ocean. The sea surface temperature dependency of evaporation is the major damping mechanism. The simulated changes in surface solar radiation vary considerably among models and are highly correlated with inter‐model variability in SST trend, illustrating the need to reduce uncertainties in cloud simulation.