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On the resolution sensitivity in a GFDL global atmospheric model
  • Pu Lin,
  • Yi Ming,
  • Thomas Robinson
Pu Lin
Princeton University

Corresponding Author:pulin@princeton.edu

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Yi Ming
Geophysical Fluid Dynamics Laboratory
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Thomas Robinson
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We performed a series of aquaplanet simulations at the resolution from 50km to 6km with identical parameterization settings using the Geophysical Fluid Dynamics Laboratory’s Atmosphere Model version 4 implemented with the two-moment Morrison-Gettelman cloud microphysics with prognostic precipitation (GFDL AM4-MG2). At the finer resolution, the global mean resolved-scale precipitation increases and that from cumulus parameterization decreases. The model also simulates less/thinner clouds over the low latitudes and more/thicker clouds over the high latitudes as the resolution increases. The precipitation over the deep tropics is investigated in detail. We find little resolution sensitivity in the daily mean precipitation extremes. The increment of the equatorial resolved precipitation with resolution mainly comes from precipitation of moderate intensity occurring irrespective of changes in vertical velocity intensity. We report a robust sensitivity in the convective organization over the deep tropics to the model resolution. In simulations of finer resolution, the localized convection is suppressed, and the organized convective system associated with large-scale circulations becomes more prominent.