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Two-moment bulk cloud microphysics with prognostic precipitation in the GFDL CM4.0 model: Performance and simulation characteristics
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  • Huan Guo,
  • Yi Ming,
  • Song-Miao Fan,
  • Andrew T. Wittenberg,
  • Rong Zhang,
  • Ming Zhao,
  • Linjiong Zhou
Huan Guo
NOAA/GFDL

Corresponding Author:[email protected]

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Yi Ming
Geophysical Fluid Dynamics Laboratory
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Song-Miao Fan
National Oceanic and Atmospheric Administration (NOAA)
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Andrew T. Wittenberg
NOAA Geophysical Fluid Dynamics Laboratory
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Rong Zhang
GFDL/NOAA
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Ming Zhao
GFDL/NOAA
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Linjiong Zhou
Geophysical Fluid Dynamics Laboratory
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Abstract

We describe the model performance and simulation characteristics of a new global coupled climate model configuration, CM4-MG2. Beginning with the Geophysical Fluid Dynamics Laboratory’s fourth-generation physical climate model (CM4.0), we incorporate a two-moment Morrison-Gettelman bulk cloud microphysics scheme with prognostic precipitation (MG2), and a mineral dust and temperature-dependent cloud ice nucleation scheme. We then conduct and analyze a set of fully coupled atmosphere-ocean-land-sea ice simulations, following Coupled Model Intercomparison Project Phase 6 (CMIP6) protocols. CM4-MG2 generally captures CM4.0’s baseline simulation characteristics, but with several improvements, including better marine stratocumulus clouds off the west coasts of Africa and North and South America, a reduced bias toward “double” Intertropical Convergence Zones south of the equator, and a stronger Madden-Julian Oscillation (MJO). Some degraded features are also identified, including excessive Arctic sea ice extent and a stronger-than-observed El Nino-Southern Oscillation (ENSO). Compared to CM4.0, the climate sensitivity is reduced by about 10\% in CM4-MG2.