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aerocom:optical_properties [2012-06-22 12:15:25] michaels |
aerocom:optical_properties [2022-05-31 09:29:31] (current) |
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- | ===== Questionary on Optical properties ===== | + | ATTENTION - THIS WIKI PAGE IS NO LONGER UPDATED - PLEASE GO TO [[http:// |
+ | |||
+ | ===== Questionary on Optical properties | ||
+ | |||
+ | The Phase III questionnaire is available in the following Google spreadsheet: | ||
+ | |||
+ | https:// | ||
+ | |||
+ | If you have problems accessing this spreadsheet, | ||
+ | |||
+ | ===== Questionary on Optical properties (AeroCom Phase II models)===== | ||
Questions on optical property calculations in AeroCom phase II models with the purpose of a correct interpretation of diagnosed AOD properties in the AeroCom database: | Questions on optical property calculations in AeroCom phase II models with the purpose of a correct interpretation of diagnosed AOD properties in the AeroCom database: | ||
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12) Please provide the refractive index at 0.55 microns for each aerosol species? And eventually further information on the hygroscopicity for each species. | 12) Please provide the refractive index at 0.55 microns for each aerosol species? And eventually further information on the hygroscopicity for each species. | ||
- | ==== INCA ==== | ||
- | |||
- | 1) Do you assume and how internal mixing when computing optical properties of total | ||
- | aerosol? Is Size varying? Which mixing assumption? | ||
- | |||
- | INCA uses 5 modes, two insoluble (accumulation, | ||
- | Size variation is not taken into account in the AOD calculation. Optical properties assume mean size for each mode. | ||
- | |||
- | 2) Do you differentiate between clear-sky and all-sky relative humidity and | ||
- | which one do you use for the AOD calculation, | ||
- | |||
- | In the LMDzT host model instantaneous clear-sky relative humidity is computed. This is used to compute hygroscopic growth factors, used in tabulated form, to get to AOD. | ||
- | |||
- | NOTE: The meaning of the clear-sky humidity in the LMDzT model has recently changed. Not clear how this affected the results. | ||
- | |||
- | 2b) If you differentiate, | ||
- | |||
- | All-sky AOD was never calculated. | ||
- | |||
- | 3) Is the reported-to-AeroCom AOD as asked under 2) used directly for the RF calculations? | ||
- | |||
- | No - The AeroCom AOD diagnostics are computed for a given wavelength. RF uses the broadband AOD for the SW and NIR bands used in the RF calculation. | ||
- | |||
- | 4) Would you consider the diagnosed AOD provided to the Aerocom database as representative for clear-skies? | ||
- | |||
- | yes | ||
- | |||
- | 5) If you diagnose a clear-sky | ||
- | |||
- | Growth factors for each mode are interpolated. | ||
- | |||
- | 6) Which humidity growth factor and variation do you use ? How does it depend on RH? Do you include sub-grid variability in relative humidity? | ||
- | |||
- | 11 tabulated growth factors between 0 and 90% RH and one at 95% RH. | ||
- | |||
- | No inclusion of sub-grid variability. | ||
- | |||
- | 7) Do you diagnose the aerosol water mass or aerosol water AOD? How? | ||
- | |||
- | 8) Is the diagnosed sea salt and sulfate AOD computed at ambient RH? And eventually is that using clear-sky or all-sky RH? | ||
- | |||
- | 9) Do you average nighttime and daytime values of AOD into daily averages? | ||
- | |||
- | 10) What is the single-scattering albedo of your BC, POM, DUST? Does it vary as a function of size, RH? How roughly? Which range? | ||
- | |||
- | 11) What is the absorption coefficient of BC? How is it calculated? | ||
- | |||
- | 12) Please provide the refractive index at 0.55 microns for each aerosol species? And eventually further information on the hygroscopicity for each species. | ||
===== MODELS ===== | ===== MODELS ===== | ||
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For full details and data on how AOD is calculated within GEOS-Chem, the user may refer to the FlexAOD post-processing tool: [[http:// | For full details and data on how AOD is calculated within GEOS-Chem, the user may refer to the FlexAOD post-processing tool: [[http:// | ||
+ | |||
+ | ==== INCA ==== | ||
+ | |||
+ | 1) Do you assume and how internal mixing when computing optical properties of total | ||
+ | aerosol? Is Size varying? Which mixing assumption? | ||
+ | |||
+ | INCA uses 5 modes, two insoluble (accumulation, | ||
+ | Size variation is not taken into account in the AOD calculation. Optical properties assume mean size for each mode. | ||
+ | |||
+ | 2) Do you differentiate between clear-sky and all-sky relative humidity and | ||
+ | which one do you use for the AOD calculation, | ||
+ | |||
+ | In the LMDzT host model instantaneous clear-sky relative humidity is computed. This is used to compute hygroscopic growth factors, used in tabulated form, to get to AOD. | ||
+ | |||
+ | NOTE: The meaning of the clear-sky humidity in the LMDzT model has recently changed. Not clear how this affected the results. | ||
+ | |||
+ | 2b) If you differentiate, | ||
+ | |||
+ | All-sky AOD was never calculated. | ||
+ | |||
+ | 3) Is the reported-to-AeroCom AOD as asked under 2) used directly for the RF calculations? | ||
+ | |||
+ | No - The AeroCom AOD diagnostics are computed for a given wavelength. RF uses the broadband AOD for the SW and NIR bands used in the RF calculation. | ||
+ | |||
+ | 4) Would you consider the diagnosed AOD provided to the Aerocom database as representative for clear-skies? | ||
+ | |||
+ | yes | ||
+ | |||
+ | 5) If you diagnose a clear-sky | ||
+ | |||
+ | Growth factors for each mode are interpolated. | ||
+ | |||
+ | 6) Which humidity growth factor and variation do you use ? How does it depend on RH? Do you include sub-grid variability in relative humidity? | ||
+ | |||
+ | 11 tabulated growth factors between 0 and 90% RH and one at 95% RH. | ||
+ | No inclusion of sub-grid variability. | ||
+ | |||
+ | 7) Do you diagnose the aerosol water mass or aerosol water AOD? How? | ||
+ | |||
+ | Yes, but it does not correspond strictly to the growth factors used for AOD computation. | ||
+ | |||
+ | 8) Is the diagnosed sea salt and sulfate AOD computed at ambient RH? And eventually is that using clear-sky or all-sky RH? | ||
+ | |||
+ | Yes, clear-sky RH. | ||
+ | |||
+ | 9) Do you average nighttime and daytime values of AOD into daily averages? | ||
+ | |||
+ | daily averages | ||
+ | |||
+ | 10) What is the single-scattering albedo of your BC, POM, DUST? Does it vary as a function of size, RH? How roughly? Which range? | ||
+ | |||
+ | Depending on wavelength and RH | ||
+ | BC soluble SSA varies between 0.41 and 0.53 | ||
+ | BC insoluble SSA varies between 0.30 and 0.42 | ||
+ | OA SSA varies between 0.94 and 0.99 | ||
+ | DUST SSA varies between 0.944 and 0.987 | ||
+ | |||
+ | 11) What is the absorption coefficient of BC? How is it calculated? | ||
+ | |||
+ | from SSA | ||
+ | |||
+ | 12) Please provide the refractive index at 0.55 microns for each aerosol species? And eventually further information on the hygroscopicity for each species. | ||