Publication Abstracts

Van Diedenhoven et al. 2016

Van Diedenhoven, B., A.S. Ackerman, A.M. Fridlind, and B. Cairns, 2016: On averaging aspect ratios and distortion parameters over ice crystal population ensembles for estimating effective scattering properties. J. Atmos. Sci., 73, no. 2, 775-787, doi:10.1175/JAS-D-15-0150.1.

The use of ensemble-average values of aspect ratio and distortion parameter of hexagonal ice prisms for the estimation of ensemble-average scattering asymmetry parameters is evaluated. Using crystal aspect ratios greater than unity generally leads to ensemble-average values of aspect ratio that are inconsistent with the ensemble-average asymmetry parameters. When a definition of aspect ratio is used that limits the aspect ratio to below unity (α≤1) for both hexagonal plates and columns, the effective asymmetry parameters calculated using ensemble-average aspect ratios are generally consistent with ensemble-average asymmetry parameters, especially if aspect ratios are geometrically averaged. Ensemble-average distortion parameters generally also yield effective asymmetry parameters that are largely consistent with ensemble-average asymmetry parameters. In the case of mixtures of plates and columns, it is recommended to geometrically average the α≤1 aspect ratios and to subsequently calculate the effective asymmetry parameter using a column or plate geometry when the contribution by columns to a given mixture's total projected area is greater or lower than 50%, respectively. In addition, we show that ensemble-average aspect ratios, distortion parameters and asymmetry parameters can generally be retrieved accurately from simulated multi-directional polarization measurements based on mixtures of varying columns and plates. However, such retrievals tend to be somewhat biased toward yielding column-like aspect ratios. Furthermore, generally large retrieval errors can occur for mixtures with approximately equal contributions of columns and plates and for ensembles with strong contributions of thin plates.

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BibTeX Citation

@article{va09200d,
  author={van Diedenhoven, B. and Ackerman, A. S. and Fridlind, A. M. and Cairns, B.},
  title={On averaging aspect ratios and distortion parameters over ice crystal population ensembles for estimating effective scattering properties},
  year={2016},
  journal={J. Atmos. Sci.},
  volume={73},
  number={2},
  pages={775--787},
  doi={10.1175/JAS-D-15-0150.1},
}

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RIS Citation

TY  - JOUR
ID  - va09200d
AU  - van Diedenhoven, B.
AU  - Ackerman, A. S.
AU  - Fridlind, A. M.
AU  - Cairns, B.
PY  - 2016
TI  - On averaging aspect ratios and distortion parameters over ice crystal population ensembles for estimating effective scattering properties
JA  - J. Atmos. Sci.
VL  - 73
IS  - 2
SP  - 775
EP  - 787
DO  - 10.1175/JAS-D-15-0150.1
ER  -

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