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aerocom:optical_properties [2012-03-22 14:33:05] huisheng.bian-1@nasa.gov [MODELS] |
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- | ===== Questionary on Optical properties ===== | + | ATTENTION - THIS WIKI PAGE IS NO LONGER UPDATED - PLEASE GO TO [[http:// |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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1) Do you assume and how internal mixing when computing optical properties of total | 1) Do you assume and how internal mixing when computing optical properties of total | ||
- | aerosol? Is Size varying? Which mixing assumption? | + | aerosol? Is Size varying? Which mixing assumption? |
2) Do you differentiate between clear-sky and all-sky relative humidity and | 2) Do you differentiate between clear-sky and all-sky relative humidity and | ||
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2b) If you differentiate, | 2b) If you differentiate, | ||
- | 3) Is the reported-to-AeroCom AOD as asked under 2) used directly for the RF calculations? | + | 3) Is the reported-to-AeroCom AOD as asked under 2) used directly for the RF calculations? |
4) Would you consider the diagnosed AOD provided to the Aerocom database as representative for clear-skies? | 4) Would you consider the diagnosed AOD provided to the Aerocom database as representative for clear-skies? | ||
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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? | 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? | ||
- | 7) Do you diagnose the aerosol water mass or aerosol water AOD? How? | + | 7) Do you diagnose the aerosol water mass or aerosol |
- | 8) Is the diagnosed sea salt and sulfate AOD computed at ambient RH? And eventually is that using clear-sky or all-sky RH? | + | 8) Is the diagnosed sea salt and sulfate AOD computed at ambient RH? And eventually is that using clear-sky or all-sky |
9) Do you average nighttime and daytime values of AOD into daily averages? | 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? | + | 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? | 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. | 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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==== GISS-modelE.A2.* ==== | ==== GISS-modelE.A2.* ==== | ||
- | + | 1) Do you assume and how internal mixing when computing optical properties of total aerosol? Is Size varying? Which mixing assumption? | |
+ | |||
+ | Aerosol are externally mixed, size distributions are prescribed | ||
+ | |||
+ | 2) Do you differentiate between clear-sky and all-sky relative humidity and which one do you use for the AOD calculation, | ||
+ | |||
+ | We do not differentiate between clear sky and all sky humidity, but we provide both, clear and all sky AOD for AeroCOm. | ||
+ | |||
+ | 3) Is the reported-to-AeroCom AOD as asked under 2) used directly for the RF calculations? | ||
+ | |||
+ | Yes | ||
+ | |||
+ | 4) Would you consider the diagnosed AOD provided to the Aerocom database as representative for clear-skies? | ||
+ | |||
+ | We provided both clear and all sky. | ||
+ | |||
+ | 5) If you diagnose a clear-sky AOD ⇒ How do you compute it? What are the assumptions on RH? Any threshold of RH you use? Cloud fraction weighting to derive a monthly average Clear-sky AOD? | ||
+ | |||
+ | Clear sky is defined when the Monte Carlo sampling of cloud fraction sees zero cloud fraction in the column. | ||
+ | |||
+ | 6) Which humidity growth factor and variation do you use? How does it depend on RH? | ||
+ | |||
+ | Sea salt, nitrate and sulfate get humidified following Lacis and Oinas 1991 and depends on ambient RH | ||
+ | |||
+ | Do you include sub-grid variability in relative humidity? | ||
+ | |||
+ | No | ||
+ | |||
+ | We use different parameterizations for sulfate and sea salt. | ||
+ | |||
+ | Yes | ||
+ | |||
+ | 7) Do you diagnose the aerosol water mass or aerosol water AOD? How? | ||
+ | |||
+ | No | ||
+ | |||
+ | 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 we use ambient all sky RH. | ||
+ | |||
+ | 9) Do you average nighttime and daytime values of AOD into daily averages? | ||
+ | |||
+ | Yes | ||
+ | |||
+ | 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? | ||
+ | |||
+ | BC absorption is calculated based on BC mass, an BC enhancement factor of 1.5 is applied to take into account BC enhancement effect due to internal mixing. | ||
+ | |||
+ | 12) Please provide the refractive index at 0.55 microns for each aerosol species? And eventually further information on the hygroscopicity for each species. | ||
+ | |||
+ | The following refractive indices at 550nm are used in this study: Sulfate (1.528-1.e-7i), | ||
==== GISS-MATRIX.A2.* ==== | ==== GISS-MATRIX.A2.* ==== | ||
- | + | 1) Do you assume and how internal mixing when computing optical properties of total aerosol? Is Size varying? Which mixing assumption? | |
+ | |||
+ | Mixing state is taken into consideration. Particles including BC have core shell structure; other particles use volume mixing approach. The size is prognostic and the mixing state assumption follows the population definitions in Bauer et al 2008 ACP | ||
+ | |||
+ | 2) Do you differentiate between clear-sky and all-sky relative humidity and which one do you use for the AOD calculation, | ||
+ | |||
+ | We do not differentiate between clear sky and all sky humidity, but we provide both, clear and all sky AOD for AeroCOm. | ||
+ | |||
+ | 3) Is the reported-to-AeroCom AOD as asked under 2) used directly for the RF calculations? | ||
+ | |||
+ | Yes | ||
+ | |||
+ | 4) Would you consider the diagnosed AOD provided to the Aerocom database as representative for clear-skies? | ||
+ | |||
+ | We provided both clear and all sky. | ||
+ | |||
+ | 5) If you diagnose a clear-sky AOD ⇒ How do you compute it? What are the assumptions on RH? Any threshold of RH you use? Cloud fraction weighting to derive a monthly average Clear-sky AOD? | ||
+ | |||
+ | Clear sky is defined when the Monte Carlo sampling of cloud fraction sees zero cloud fraction in the column. | ||
+ | |||
+ | 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? | ||
+ | |||
+ | We calculate the uptake of water following the thermodynamical model EQSAM and for Sea salt using the Lewis parameterization (Lewis and Schwartz 2004) | ||
+ | |||
+ | 7) Do you diagnose the aerosol water mass or aerosol water AOD? How? | ||
+ | |||
+ | No, aerosol water is one component that determines the mixing state of aerosols. Aerosol water is tracked for each aerosol population. | ||
+ | |||
+ | 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 we use ambient all sky RH. | ||
+ | |||
+ | 9) Do you average nighttime and daytime values of AOD into daily averages? | ||
+ | |||
+ | Yes | ||
+ | |||
+ | 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? | ||
+ | |||
+ | BC absorption is calculated depending on aerosol mixing state – see question 1) | ||
+ | |||
+ | 12) Please provide the refractive index at 0.55 microns for each aerosol species? And eventually further information on the hygroscopicity for each species. | ||
+ | |||
+ | The following refractive indices at 550nm are used: Sulfate (1.528-1.e-7i), | ||
==== BCC_AGCM2.0.1_CAM.A2.* ==== | ==== BCC_AGCM2.0.1_CAM.A2.* ==== | ||
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1) Do you assume and how internal mixing when computing optical properties of total | 1) Do you assume and how internal mixing when computing optical properties of total | ||
- | aerosol? Is Size varying? Which mixing assumption? | + | 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 | 2) Do you differentiate between clear-sky and all-sky relative humidity and | ||
which one do you use for the AOD calculation, | 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, | 2b) If you differentiate, | ||
- | 3) Is the reported-to-AeroCom AOD as asked under 2) used directly for the RF calculations? | + | 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? | 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 | 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? | 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? | ||
- | 7) Do you diagnose the aerosol water mass or aerosol | + | 11 tabulated growth factors between 0 and 90% RH and one at 95% RH. |
+ | No inclusion of sub-grid variability. | ||
- | 8) Is the diagnosed sea salt and sulfate AOD computed at ambient RH? And eventually is that using clear-sky or all-sky | + | 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? | 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? | + | 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? | 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. | 12) Please provide the refractive index at 0.55 microns for each aerosol species? And eventually further information on the hygroscopicity for each species. | ||
+ | |||
+ | |||