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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. - PowerPoint PPT Presentation
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A cloud schemeincluding indirect aerosol effects on
ice and liquid cloud particlesin the MRI Earth System Model
SAKAMI, T., T.OSE and S. YUKIMOTOwith 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 (FY2005-2009: 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
Tiedtke cloud
Arakawa-Schubert
Incorporated microphysical schemes for cloud phase change processes
Murakami(1994) for sublimationMurakami(1999) for depositionRutldge(1983) for depositional growth
Bigg(1953) for immersion freezingLohman(2006) for contact freezing
Detrained ice/liquid depending on T
Levkov (1992) for accretion
Rotstayn(2000) for autoconversion and collection
Melting occurs at 273.15K
Incorporated microphysical schemesfor 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(2006) 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) arediagnosed from a given aerosol mass in the model.
Sulfate
BC
OC
SeasaltDust
Cloud Cover in comparison with ECHAM5-RH in U. Lohmann et al. (2007)
ECHAM5-RH
MRISCdetrainment
MRI
MRIASdetrainment
Grid-averaged Cloud Liquid Waterin comparison with ECHAM5-RH in U. Lohmann et al. (2007)
ParticleNumber1/cm3
Massmg/kg
ECHAM5-RH
MRI
In-cloud particle concentration (#/cm3) at 850-950hPain comparison with GFDL_AM2 in Ming (2007)
GFDLPrognostic
GFDLDiagnostic
MRI
MRIAerosol
Grid-averaged Cloud Ice Water in comparison with ECHAM5-RH in U. Lohmann et al. (2007)
ECHAM5-RH
MRI
Number1/cm3
Massmg/kg
Grid-averaged Cloud Ice Water (mg/m3) in comparison with CAM in Liu et al. (2007)
CAMICE
CAMREF
OBSMRI
Cloud radiative effects tend to be overestimated probably due to small cloud effective radius.
ERBEDSW
ERBEULW
MRIDSW
MRIULW
OUTLINE
• MRI-ESM and cloud models
• Performance of cloud models
• Sensitivity experiments for 2×CO2
• Summary
Radiative forcing for 2xCO2in comparison with Fig.3 in Gregory and Webb (2008)
• Hansen et al. (2002) type approach
• (4xCO2-1xCO2)*0.5
• Fixed SSTs • 3 years runs
0.58
-1.15
3.75
0.50
3.68
CLRLW
CLRSW
CLDLW
CLDSW
NET
Cloud forcing seems to be well related to cloud cover changes.
CLOUDChange
DSW
DLW
WARMING
COOLING
CuDetrainmentChange
SCDetrainmentchange
950-1000hPa clouds increase over their climatologically abundant region .
950-1000hPa Climatological Cloud Cover
950-1000hPa Cloud Cover Change
950-1000hPa cloud increase tend to contribute SW radiative cooling. Strong SW radiative warming due to suppressed cumulus is more clear.
Negative DSW TOAChange
950-1000hPa Cloud Cover Increase
Shallow Cumulus detrainment change contributes to 800-950hPa cloud changes to some extent, but small impact on cloud forcing in the model.
SCClimate
SCChange
800-950hPaClimateCloud
800-950hPaCloudChange
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.