[A-CG34] Projection and detection of global environmental change

[ACG34-01] Development of the Model for Interdisciplinary Research on Climate version 7 (MIROC7)

★Invited Papers

*Nagio Hirota¹, Takuro Michibata², Yoko Yamagami³, Hiroaki Tatebe³, Kentaroh Suzuki⁴, Masahiro Watanabe⁴, Takao Kawasaki⁴, Tomoko Nitta⁵, Fuyuki SAITO³, Koji Ogochi³, Miho Sekiguchi⁶, Shingo Watanabe³, Hideo Shiogama¹, Tomoo Ogura¹, Toshihiko Takemura⁷, Tomoki Ohno⁴, Manabu Abe³, Kei Yoshimura⁵, Hideaki Kawai⁸, Minoru Chikira¹, Hisashi Yashiro¹, Daisuke Goto¹ (1.National Institute for Environmental Studies, 2.Okayama University, 3.Japan Agency for Marine-Earth Science and Technology, 4.Atmosphere and Ocean Research Institute, University of Tokyo, 5.Institute of Industrial Science, the University of Tokyo, 6.Tokyo University of Marine Science and Technology, 7.Research Institute for Applied Mechanics, Kyushu University, 8.Meteorological Research Institute)

Keywords:climate model, CMIP7, climate projections, energy budget

A new version of the Model for Interdisciplinary Research on Climate, called MIROC7, is under development by a Japanese modeling community. The previous version MIROC6 showed good performances in representing climate mean states and natural variabilities, such as ENSO, MJO, QBO and SSW. However, some notable weaknesses remained in MIROC6. In particular, greenhouse effects of water vapor and sunshade effects of clouds were overly strong compared with observations, resulting in large biases in the energy budget. Moreover, acceleration of global warming by clouds (cloud feedback) was too weak compared with a likely range of cloud feedback values of WCRP assessments. Major updates from MIROC6 to MIROC7 are: more sophisticated cloud physics with prognostic treatment of precipitating particles; radiation processes; ocean mixing processes; and sea-ice treatments. Our preliminary results indicate that the biases in the energy budget is alleviated and cloud feedback is strengthened toward more positive. Given that cloud representation is improved and cloud feedback is more consistent with the WCRP assessments, climate projections by MIROC7 is likely to be more reliable compared with those by previous versions. Further developments is underway toward the seventh phase of Coupled Model Intercomparison Project.
Acknowledgments: This research is supported by the SENTAN Program (JPMXD0722680395) by MEXT, Japan. Simulations were performed on the Earth Simulator (JAMSTEC) and NEC SX-AURORA (NIES) were used.