Fast and Slow Responses of Equatorial SST Pattern to CO2 Forcing
Abstract
The changes of sea surface temperature and circulation due to anthropogenic warming are usually divided into fast and slow components. An enhanced equatorial warming pattern over the tropical ocean and the weakening of the Walker circulation are well-known slow responses to CO2forcing. However, because of the uncertainty brought by the internal variability, little is known about the changes of the tropical atmospheric and oceanic circulation during the first few years after quadrupling CO2. Here, a large initial condition abrupt 4xCO2ensemble experiment of Community Earth System Modeling (CESM) is used to investigate how atmosphere, land and ocean response to CO2in the first 2 years(fast) and equilibrium(slow) time period. An initial cooling pattern over the tropical Pacific Ocean is founded. A strong land-sea contrast, rapid mixed layer adjustment and cloud radiative effect are responsible for shaping this initial cooling pattern. After a few decades, the weakening of anomalous easterlies and smoothing of vertical temperature gradient gradually turn this fast cooling to slow warming pattern.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGC31G1274L
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSES;
- 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSES;
- 4805 Biogeochemical cycles;
- processes;
- and modeling;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL;
- 4215 Climate and interannual variability;
- OCEANOGRAPHY: GENERAL