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SAKAMI, T., T.OSE and S. YUKIMOTO

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.

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SAKAMI, T., T.OSE and S. YUKIMOTO

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  1. A cloud schemeincluding indirect aerosol effects on ice and liquid cloud particlesin 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.

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

  3. Development of Earth System Model for Global Warming Projection (FY2005-2009: S. YUKIMOTO)

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

  5. 2-moment cloud microphysics schemes are incorporated in the MRI-ESM. OLD Cloud (qc) NEW Cloud (qc,qi,Nc,Ni) Tiedtke cloud Tiedtke cloud Arakawa-Schubert Arakawa-Schubert

  6. Incorporated microphysical schemes for cloud phase change processes • Murakami(1994) for sublimation • Murakami(1999) for deposition • Rutldge(1983) for depositional growth • Rotstayn(2000) for autoconversion and collection • Bigg(1953) for immersion freezing • Lohman(2006) for contact freezing • Melting occurs at 273.15K • Levkov (1992) for accretion • Detrained ice/liquid depending on T

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

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

  9. Preliminary experiments Experiments 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) • 3 years run • MRI-AGCM (TL159L46) • Climatological SST • Climatological aerosol mass • No aerosol transport model • No direct effect of aerosol

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

  11. Cloud Cover in comparison with ECHAM5-RH in U. Lohmann et al. (2007) ECHAM5-RH MRI MRI SC detrainment MRI AS detrainment

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

  13. In-cloud particle concentration (#/cm3) at 850-950hPain comparison with GFDL_AM2 in Ming (2007) GFDL Prognostic MRI MRI Aerosol GFDL Diagnostic

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

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

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

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

  18. Radiative forcing for 2xCO2in comparison with Fig.3 in Gregory and Webb (2008) 3.75 3.68 • Hansen et al. (2002) type approach • (4xCO2-1xCO2)*0.5 • Fixed SSTs • 3 years runs CLD LW 0.58 0.50 CLD SW NET CLR LW CLR SW -1.15

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

  20. 950-1000hPa clouds increase over their climatologically abundant region . 950-1000hPa Climatological Cloud Cover 950-1000hPa Cloud Cover Change

  21. 950-1000hPa cloud increase tend to contribute SW radiative cooling. Strong SW radiative warming due to suppressed cumulus is more clear. Negative DSW TOA Change 950-1000hPa Cloud Cover Increase

  22. Shallow Cumulus detrainment change contributes to 800-950hPa cloud changes to some extent, but small impact on cloud forcing in the model. SC Climate SC Change 800-950hPa Cloud Change 800-950hPa Climate Cloud

  23. 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.

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