Development, verification, and natural variability in MIROC5

Overview of decadal climate prediction using a coupled climate model MIROC

Masahiro Watanabe
Yoshimitsu Chikamoto
AORI, University of Tokyo


A Japanese community climate model, called Model for Interdisciplinary Research on Climate (MIROC), has been developed for use of various aspects of climate research. We are currently under operation of MIROC with three types of configuration: a high-resolution climate model for the decadal climate prediction, a low-resolution Earth system model, and a low-resolution new version of the climate model (MIROC5). In this talk, I would like to introduce outcomes from MIROC5, in which many of the atmospheric parameterization schemes have been updated. Improvements in the climate simulation with MIROC5 and a high sensitivity of the ENSO simulation to a perturbation in the cumulus convection scheme are presented.

Toward coming IPCC AR5, we have performed decadal climate prediction using three versions of the coupled atmosphere-ocean model MIROC. In these hindcast experiments, initial conditions were obtained with an anomaly assimilation procedure using the observed oceanic temperature and salinity while prescribing natural and anthropogenic forcing based on the IPCC emission scenarios. Our hindcast experiments show that initialization contributes to enhance the predictive skills of AMO and PDO indices for several years in advance. In addition to these major climate phenomena, the hindcast experiments tend to simulate a pattern of stepwise sea surface temperature increase in the Pacific during the late 1990s. Although further studies are need to enhance predictive skills of decadal climate variability, our results suggest that the decadal climate prediction has a potential to provide useful information in order to solve socioeconomic problems arising from climate change.