Cloud Optical Properties
Last updated: 10 Jan 2021
The programs in these pages use advanced spectral averaging methods to calculate cloud optical properties.
The optical properties and the effective size and aspect ratio are calculated for each PSD in an ensemble of 7500 particle size distributions. The calculations, for each single wavelength data is based on Fu (DOI) and Hu & Stamnes (DOI). The collection of these 7500 points are fitted to a Padé approximation using a non-linear fitting algorithm selected to adequately reproduce asymptotic behavior
This way, we can extend the effective size range to include large hydro meteors categories such as snow, graupel and rain.
For a full discussion on the scientific aspects and numerical implementation see the Parametrizations of Liquid and Ice Clouds' Optical Properties Parametrizations in Operational Numerical Weather Prediction Models.
Related COSMO priority projects are T2(RC)2 and CAIIR.
On how to run the programs yourself, using the web interface, see this user manual.
To run your own simulations, you will need a username and password. These are free and you can get them by contacting Harel Muskatel. When you have your credentials, you can start.
The authors of the programs are Ulrich Blahak (DWD) and Harel Muskatel (IMS). You may contact Harel Muskatel for further details.
- Muskatel, H..B.; Blahak, U.; Khain, P.; Levi, Y.; Fu, Q. Parametrizations of Liquid and Ice Clouds’ Optical Properties in Operational Numerical Weather Prediction Models. Atmosphere 2021, 12, 89.
- Fu, Q., 1996: An Accurate Parameterization of the Solar Radiative Properties of Cirrus Clouds for Climate Models.
J. Climate, 9, 2058–2082.
- Fu, Q., Yang, P., & Sun, W., 1998: An Accurate Parameterization of the Infrared Radiative Properties of Cirrus Clouds for Climate Models.
Journal of Climate, 11(9), 2223-2237.
- Fu, Q., 2007: A New Parameterization of an Asymmetry Factor of Cirrus Clouds for Climate Models.
J. Atmos. Sci., 64, 4140–4150.
- Hu, Y.X. and K. Stamnes, 1993: An Accurate Parameterization of the Radiative Properties of Water Clouds Suitable for Use in Climate Models.
J. Climate, 6, 728–742.