A cloud scheme including indirect aerosol effects on ice and liquid cloud particles in the MRI Earth System Model SAKAMI, T., T.OSE and S. YUKIMOTO with the MRI Earth System Modeling Group (Meteorological Research Institute, Tsukuba, JAPAN) Today’s speaker is T.OSE.

OUTLINE MRI-ESM and cloud models Performance of cloud models Sensitivity experiments for 2×CO2 Summary

Development of Earth System Model for Global Warming Projection (FY : S. YUKIMOTO)

Tanaka, T. Y., and M. Chiba, 2005

2-moment cloud microphysics schemes are incorporated in the MRI-ESM. NEW Cloud (qc,qi,Nc,Ni)OLD Cloud (qc) Arakawa-Schubert Tiedtke cloud Arakawa- Schubert

Incorporated microphysical schemes for cloud phase change processes Murakami(1994) for sublimation Murakami(1999) for deposition Rutldge(1983) for depositional growth Bigg(1953) for immersion freezing Lohman(2006) for contact freezing Detrained ice/liquid depending on T Levkov (1992) for accretion Rotstayn(2000) for autoconversion and collection Melting occurs at K

Incorporated microphysical schemes for cloud particle numbers Abdul-Razzak (2000,2002) for activation to cloud droplets Karcher(2006) for activation to ice crystals Ming(2007) for Detrained number of cloud droplet and ice crystal from cumulus cloud Martin(1994),Liu(20 06) for effective radius of cloud droplets Lohmann(2002) for volume radius to get effective radius of ice crystals

OUTLINE MRI-ESM and cloud models Performance of cloud models Sensitivity experiments for 2×CO2 Summary

Preliminary experiments Experiments 3 years run MRI-AGCM (TL159L46) Climatological SST Climatological aerosol mass No aerosol transport model No direct effect of aerosol Comparisons with ECHAM5-HAM and OBS in U. Lohmann et al. (2007) NCAR CAM3 and OBS in X.Liu et al. (2007) GFDL AM2 in Ming et al. (2007)

Aerosol number concentration (#/cm3) are diagnosed from a given aerosol mass in the model. Sulfate BC OC Seasalt Dust

Cloud Cover in comparison with ECHAM5-RH in U. Lohmann et al. (2007) ECHAM 5-RH MRI SC detrain ment MRI AS detrain ment

Grid-averaged Cloud Liquid Water in comparison with ECHAM5-RH in U. Lohmann et al. (2007) Particle Number 1/cm3 Mass mg/kg ECHA M5- RH MRI

In-cloud particle concentration (#/cm3) at hPa in comparison with GFDL_AM2 in Ming (2007) GFDL Progno stic GFDL Diagno stic MRI Aerosol

Grid-averaged Cloud Ice Water in comparison with ECHAM5-RH in U. Lohmann et al. (2007) ECHA M5- RH MRI Number 1/cm3 Mass mg/kg

Grid-averaged Cloud Ice Water (mg/m3) in comparison with CAM in Liu et al. (2007) CAM ICE CAM REF OBS MRI

Cloud radiative effects tend to be overestimated probably due to small cloud effective radius. ERBE DSW ERBE ULW MRI DSW MRI ULW

OUTLINE MRI-ESM and cloud models Performance of cloud models Sensitivity experiments for 2×CO2 Summary

Radiative forcing for 2xCO2 in comparison with Fig.3 in Gregory and Webb (2008) Hansen et al. (2002) type approach (4xCO2- 1xCO2)*0.5 Fixed SSTs 3 years runs CLR LW CLR SW CLD LW CLD SW NET

Cloud forcing seems to be well related to cloud cover changes. CLOUD Change DSW DLW WARMING COOLING Cu Detrain ment Change SC Detrain ment change

hPa clouds increase over their climatologically abundant region hPa Climatological Cloud Cover hPa Cloud Cover Change

hPa cloud increase tend to contribute SW radiative cooling. Strong SW radiative warming due to suppressed cumulus is more clear. Negative DSW TOA Change hPa Cloud Cover Increase

Shallow Cumulus detrainment change contributes to hPa cloud changes to some extent, but small impact on cloud forcing in the model. SC Climate SC Change hPa Climate Cloud hPa Cloud Change

SUMMARY The 2-moment liquid and ice cloud models including cumulus-related activation and detrainment processes are incorporated in the MRI-ESM. Those cloud models basically seem to show good performance. Suppressed deep cumulus detrainments and enhanced low-level clouds seem to be significant for radiative forcing change in a sensitivity experiment. Indirect effects of the model need to be examined in different aerosol environments.