The Role of Ocean in Model Simulations of Global and Regional Anthropogenic Climate Change

Abstract:

AGCM simulation of climate variability has been long criticized for its lack of coupling with an underlying ocean. This study shows that the lack of coupling does not undermine AGCM’s ability to simulate global and regional anthropogenic climate change. A comparison between coupled and AGCM simulations shows that anthropogenic climate change can be well reproduced by AGCM and errors due to lack of coupling are only related to internal variability. These results are confirmed using a stochastic linear model. Furthermore, in association with a previous study which showed that atmospheric circulation and precipitation over land are insensitive to the pattern of future SST change, we found that anthropogenic climate change over land can be well simulated with AGCM forced with only radiative forcing and a uniform warming. This result shows that ocean model is not necessary for simulations of future land climate change.