Version 3: Ice Cloud Bulk Single-Scattering Property Models that include the Full Phase Matrix

Ice cloud bulk single-scattering properties are available for both individual wavelengths from 0.4 to 3.0 µm (i.e., spectral models) and also a narrowband sensor called PARASOL. The influence of particle roughening is described in Baum et al. (2010); the habit mixture is described in Baum et al. (2011) and Cole et al. (2012), with full references at the bottom of this page.

There are currently 4 sets of models available for PARASOL, each of which assumes that the ice particles are severely roughened:

(1) One set of models is based on a general habit mixture (GHM) involving a set of 9 habits: solid/hollow bullet rosettes, solid/hollow columns, plates, droxtals, small/large aggregate of plates, and an aggregate of solid columns.

(2) Another set of models is assumes the use of only solid bullet rosettes (SBR).

(3) A third set of models assumes the use of only hollow bullet rosettes (HBR).

(4) A fourth set of models is based on the use of only solid columns (forgive me - just couldn't come up with a decent 3-letter acronym for it).

The files are in NetCDF format with a single file per channel. The single-scattering properties are a function of effective diameter and include the asymmetry parameter, single-scattering albedo, and the 6 components of the full phase matrix, each at 498 angles (also provided). The phase matrix includes P₁₁, -P₁₂/P₁₁, P₂₂/P₁₁, P₃₃/P₁₁, P₄₃/P₁₁, and P₄₄/P₁₁. Additionally, the models include the average ice water content inferred from idealized habits and the microphysical data used to generate the models (provided for general information), and the extinction coefficient (β) divided by the IWC. This parameter might be useful for modelers. The NetCDF files also include the wavelength, the version number of the models (currently at 3.5) and the creation date. The spectral models are combined in a tar file.

The "Download Models" button at the top of the page provides access to the models. Note that there is a new system in place at SSEC and we now ask that you register before downloading data - all we ask for is your name and email address. Since there will be updates in the future, we hope that you will permit us to include you on an email list so that we can send a brief note with what has changed in each subsequent version. So when you register, there will be a box that asks you whether you want to be on an email list - it is voluntary on your part.

Ben Cole (Texas A&M University) has a paper in press that provides more information on the PARASOL models, with the reference below. Ping Yang also has a paper in press that describes the scattering models and methodology used to generate the database of ice particle single scattering properties.

Impertinent References:

Cole, B., P. Yang, B. A. Baum,J. Riedi, L. Labonnote, F. Thieuleux, and S. Platnick: Comparison of PARASOL observations with polarized reflectances simulated using different ice habit mixtures. In press, J. Appl. Meteor. Clim.

Yang, P., L. Bi, B. A. Baum, K.-N. Liou, G. Kattawar, M. Mishchenko, and B. Cole: Spectrally consistent scattering, absorption, and polarization properties of atmospheric ice crystals at wavelengths from 0.2 µm to 100 µm. In press, J. Atmos. Sci.

Baum, B. A., P. Yang, A. J. Heymsfield, C. Schmitt, Y. Xie, A. Bansemer, Y. X. Hu, and Z. Zhang, 2011: Improvements to shortwave bulk scattering and absorption models for the remote sensing of ice clouds. J. Appl. Meteor. Clim., 50, 1037-1056.

Baum, B. A., P. Yang, Y.-X. Hu , and Q. Feng, 2010: The impact of ice particle roughness on the scattering phase matrix. J. Quant. Spectrosc. Radiant. Transfer, 111, doi:10.1016/j.jqsrt.2010.07.008, 2534-2549.

Note: if you have questions or find problems, please let me know (send email to Bryan Baum) so I can look into the issue. If there is a problem, I want to get it fixed.