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Different transient climate responses of two versions of an atmosphere‐ocean coupled general circulation model
Author(s) -
Yokohata T.,
Emori S.,
Nozawa T.,
Ogura T.,
Okada N.,
Suzuki T.,
Tsushima Y.,
Kawamiya M.,
AbeOuchi A.,
Hasumi H.,
Sumi A.,
Kimoto M.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl027966
Subject(s) - general circulation model , climatology , atmosphere (unit) , environmental science , climate change , climate model , climate sensitivity , atmospheric sciences , transient (computer programming) , albedo (alchemy) , ocean general circulation model , ocean current , sea surface temperature , meteorology , geology , oceanography , physics , art history , operating system , art , performance art , computer science
The Model for Interdisciplinary Research on Climate (MIROC), an atmosphere‐ocean coupled general circulation model (AOGCM), has two versions with different resolutions, high (Hi‐Res) and medium (Mid‐Res). While their equilibrium climate sensitivities (ECS) to CO 2 increases are similar, the transient climate response (TCR) of the Hi‐Res version is larger than that of the Mid‐Res version. The former shows the highest transient response among the Intergovernmental Panel on Climate Change (IPCC) fourth assessment report (AR4) climate models. Our climate feedback analysis indicates that the higher TCR of the Hi‐Res version mainly comes from its larger ice‐albedo feedback (SFC‐SW) and lower ocean heat uptake (OHU). Since the Hi‐Res version shows better agreement with observation than the Mid‐Res version concerning the factors that affect the SFC‐SW and OHU, the TCR of the Hi‐Res version is not considered to be unrealistic compared to that of the Mid‐Res version. On the other hand, the two versions have similar SFC‐SW values and negligible OHU in ECS experiments performed by the atmosphere‐slab ocean coupled general circulation model (ASGCM). In the ASGCM, the difference in SFC‐SW between the two versions was likely suppressed due to artificial fluxes applied to the ocean and sea‐ice system.