Fast and Slow Response to Global Warming: Sea Surface Temperature and Precipitation Patterns
The time-dependent response of sea surface temperature (SST) to global warming and the associated atmospheric changes are investigated based on a 1 % year-1 CO2 increase to quadrupling experiment of the Geophysical Fluid Dynamics Laboratory climate model version 2.1. The SST response consist of a fa...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.422.2359 http://iprc.soest.hawaii.edu/users/xie/long-slow-jc14.pdf |
| Summary: | The time-dependent response of sea surface temperature (SST) to global warming and the associated atmospheric changes are investigated based on a 1 % year-1 CO2 increase to quadrupling experiment of the Geophysical Fluid Dynamics Laboratory climate model version 2.1. The SST response consist of a fast component for which the ocean mixed layer is in quasi-equilibrium with the radiative forcing, and a slow component due to the gradual warming of the deeper ocean in and beneath the thermocline. A diagnostic method is proposed to isolate spatial patterns of the fast and slow response. The deep ocean warming retards the surface warming in the fast response but turns into a forcing for the slow response. As a result, the fast and slow responses are nearly opposite to each other in spatial pattern, especially over the subpolar North Atlantic/Southern Ocean of the deep/bottom water formation, and in interhemispheric SST gradient between the southern and northern subtropics. Wind-evaporation-SST feedback is an additional mechanism for the SST pattern formation in the tropics. Analyses of a Coupled Model Intercomparison Project Phase 5 (CMIP5) multi-model ensemble of global warming simulations confirm the validity of the diagnostic method that separates the fast and slow response. Tropical annual rainfall change follows the SST warming pattern both in the fast and slow response in CMIP5, increasing where the SST increase exceeds the tropical mean warming. 2 |
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