Answer · confidence: strong
How do radiative transfer models predict sky brightness when water-swollen particles are added to a clean-air column?
The LBLDIS radiative transfer model simulates the Aerosol Radiative Effect by adding aerosol information to a clean-air baseline 3. Within this framework, the DISORT model is used to calculate the effects of water droplets and aerosol particles 6. The complex refractive index of these wet aerosols is determined using the volume fraction of the dry aerosol and the refractive indices of the dry particle and water 5. The most recent fact supporting this methodology is from 2025 3.
Checked 2026-10-14. Only documented and supported facts are used.
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[1] documented
Mass growth factors for aerosols can be derived from thermodynamic models to determine optical properties using Mie theory.
"Based on aerosol thermodynamic models, mass growth factor can be obtained and their optical properties can be obtained by using Mie theory with different aerosol properties and size distribution."Reconstructed expression for aerosol extinction coefficient by considering mass extinction efficiency and hygroscopic growth for polydipersed aerosol (2020)
[2] documented
At high relative humidity, aerosols including fog droplets grow substantially, which reduces the aerosol extinction coefficient and shifts extinction behavior.
"At high RH, aerosols—including fog droplets—grew substantially, reducing AE and shifting extinction behavior."Image-based observation of aerosol hygroscopic growth and extinction coefficient reversal at three wavelengths, supported by Köhler theory simulations ... - Environmental Science: Processes & Impacts
[3] documented
The LBLDIS radiative transfer model is used to simulate the Aerosol Radiative Effect (ARE) of sea salt and sulfate aerosols by adding aerosol information to a clean-air baseline.
"The AREs of two aerosols, sea salt and sulfate (ammonium sulfate), are simulated by the radiative transfer model (LBLDIS). ... The only difference in this section is that additional aerosol information is added to LBLDIS to get the model-simulated ARE AW ."ACP - Hygroscopic aerosols amplify longwave downward radiation in the Arctic
[4] documented
In the model simulations, dry sea salt aerosols are assumed to have a fixed size of 1 micrometer and a spherical shape.
"Therefore, in dry conditions, it is assumed that the size of sea salt is fixed at 1 µm and has the shape of a sphere."ACP - Hygroscopic aerosols amplify longwave downward radiation in the Arctic
[5] documented
The complex refractive index of wet aerosols is calculated using the volume fraction of the dry aerosol and the refractive indices of the dry particle and water.
"To calculate the complex refractive index ( R wet + i ⋅ I wet ) of wet aerosol, the volume fraction of dry aerosol ( Chin et al. , 2002 ) , f d , is used: ... R wet = f d R d + ( 1 - f d ) R water , I wet = f d I d + ( 1 - f d ) I water"ACP - Hygroscopic aerosols amplify longwave downward radiation in the Arctic
[6] documented
The DIScrete Ordinate Radiative Transfer (DISORT) model is used within the LBLDIS framework for the calculation of water droplets and aerosol particles.
"DIScrete Ordinate Radiative Transfer (DISORT) model ( Stamnes et al. , 1988 ) for the calculation of water droplets and aerosol particles. The coupled model is called LBLDIS ( Turner , 2005 ) ."ACP - Hygroscopic aerosols amplify longwave downward radiation in the Arctic