Difference between pages "Direct effect from GLOMAP-mode aerosol to the Edwards-Slingo radiation scheme" and "UKCA-MODE aerosol (StdTrop+aerchem): Evaluation against observations"
From UKCA
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| + | This page gives an overview of model evaluation |
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| − | The UKCA model is configured into the HadGEM3 climate model |
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| + | conducted with the UKCA StdTrop + Aerchem chemistry |
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| − | with an interface to the Edwards-Slingo radiation scheme |
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| + | coupled to the GLOMAP-mode aerosol scheme at v7.3 (N96L38). |
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| − | to allow the direct radiative effects of the GLOMAP-mode |
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| − | aerosol to feedback on the model circulation. |
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| − | A double-call method is used in this "RADAER" interface |
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| − | to allow the direct radiative forcing to be diagnosed |
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| − | and stored in the model output files. |
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| + | [[File:UKCAsurfSO4vsobs.pdf|200px|thumb|left|sulphate]] |
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| − | For the existing CLASSIC aerosol scheme used |
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| − | in HadGEM2-ES and previous HadGEM versions, |
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| − | the aerosol is considered as an external |
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| − | mixture of different aerosol types (sulphate, |
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| − | biomass, soot, biogenic and sea-salt). |
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| − | Then, for the direct aerosol forcing, the optical properties |
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| − | from each of these types was considered separately. |
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| − | The interface to the Edwards-Slingo radiation scheme used |
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| − | in HadGEM is based on look-up tables (from Mie calculations) |
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| − | for the optical properties of each particle type |
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| − | as a function of relative humidity. |
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| − | In contrast to CLASSIC, GLOMAP-mode assumes each mode |
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| − | consists of an internal mixture of the different aerosol |
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| − | components (e.g. sulphate, black carbon and organic carbon). |
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| − | The water content is evaluated within this assumption using |
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| − | the ZSR algorithm (Stokes and Robinson, 1966), using water activity data from Jacobson et al. (1996). |
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| − | Whereas the look-up tables for the CLASSIC aerosol scheme were |
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| − | based only on relative humidity and wavelength; for GLOMAP-mode, the |
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| − | information on mean particle radius and composition for each |
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| − | of the internally-mixed size modes is used. A volume-average |
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| − | mixing rule is used over the components present (including water) |
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| − | to calculate the real and imaginary parts of the refractive |
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| − | index. The particle size determines the Mie parameter in |
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| − | relation to the wavelength. The look-up tables have been |
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| − | calculated based on the integrals across each of the |
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| − | spectral bands for the short-wave and long-wave used by HadGEM. |
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| − | |||
| − | References: |
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| − | |||
| − | Bellouin, N., 2011, |
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| − | Interaction of UKCA aerosols with radiation: UKCA RADAER |
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| − | Met Office Hadley Centre Internal Report [[File:UKCA_RADAER.pdf]]. |
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| − | |||
| − | Jacobson, M. Z., Tabazadeh A. and Turco, R. P., |
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| − | Simulating equilibrium within aerosols and nonequilibrium between gases and aerosols, |
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| − | J. Geophys. Res., 101, pp. 9079-9091, 1996. |
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| − | Stokes, R.H. and Robinson, R.A., Interactions in aqueous non-electrolyte solutions: I. Solute-solvent equilibria. |
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| − | J. Phys. Chem., 70, pp. 2126-2130, 1966. |
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| − | For more details about the interface to the Edwards-Slingo |
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| − | radiation scheme and the calculations of the optical properties |
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| − | of the aerosol, please contact Nicolas Bellouin (UK Met Office) |
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| − | nicolas.bellouin@metoffice.gov.uk. |
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Revision as of 16:43, 18 February 2011
This page gives an overview of model evaluation conducted with the UKCA StdTrop + Aerchem chemistry coupled to the GLOMAP-mode aerosol scheme at v7.3 (N96L38).
