| Title: | The Aqua-Planet Experiment (APE): CONTROL SST Simulation |
| Authors: | Blackburn, Michael Browse this author |
| Williamson, David L. Browse this author |
| Nakajima, Kensuke Browse this author →KAKEN DB |
| Ohfuchi, Wataru Browse this author →KAKEN DB |
| Takahashi, Yoshiyuki O. Browse this author →KAKEN DB |
| Hayashi, Yoshi-Yuki Browse this author |
| Nakamura, Hisashi Browse this author →KAKEN DB |
| Ishiwatari, Masaki Browse this author →KAKEN DB |
| Mcgregor, John L. Browse this author |
| Borth, Hartmut Browse this author |
| Wirth, Volkmar Browse this author |
| Keywords: | comparison of atmospheric general circulation models (GCMs) |
| idealized model configuration |
| global energy buget |
| tropical wave spectrum |
| precipitation |
| Issue Date: | Sep-2013 |
| Publisher: | Meteorological soc japan |
| Journal Title: | Journal of the meteorological society of japan |
| Volume: | 91A |
| Start Page: | 17 |
| End Page: | 56 |
| Publisher DOI: | 10.2151/jmsj.2013-A02 |
| Abstract: | Climate simulations by 16 atmospheric general circulation models (AGCMs) are compared on an aqua-planet, a water-covered Earth with prescribed sea surface temperature varying only in latitude. The idealised configuration is designed to expose differences in the circulation simulated by different models. Basic features of the aqua-planet climate are characterised by comparison with Earth. The models display a wide range of behaviour. The balanced component of the tropospheric mean flow, and mid-latitude eddy covariances subject to budget constraints, vary relatively little among the models. In contrast, differences in damping in the dynamical core strongly influence transient eddy amplitudes. Historical uncertainty in modelled lower stratospheric temperatures persists in APE. Aspects of the circulation generated more directly by interactions between the resolved fluid dynamics and parameterized moist processes vary greatly. The tropical Hadley circulation forms either a single or double inter-tropical convergence zone (ITCZ) at the equator, with large variations in mean precipitation. The equatorial wave spectrum shows a wide range of precipitation intensity and propagation characteristics. Kelvin mode-like eastward propagation with remarkably constant phase speed dominates in most models. Westward propagation, less dispersive than the equatorial Rossby modes, dominates in a few models or occurs within an eastward propagating envelope in others. The mean structure of the ITCZ is related to precipitation variability, consistent with previous studies. The aqua-planet global energy balance is unknown but the models produce a surprisingly large range of top of atmosphere global net flux, dominated by differences in shortwave reflection by clouds. A number of newly developed models, not optimised for Earth climate, contribute to this. Possible reasons for differences in the optimised models are discussed. The aqua-planet configuration is intended as one component of an experimental hierarchy used to evaluate AGCMs. This comparison does suggest that the range of model behaviour could be better understood and reduced in conjunction with Earth climate simulations. Controlled experimentation is required to explore individual model behaviour and investigate convergence of the aqua-planet climate with increasing resolution. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/54604 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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