Ding (2016)

Single scattering properties of various ice shapes. Investigation on the effect of the temperature to refractive index and radiative properties

Authors

Jachen Ding

Link

Papers

Jiachen Ding, Lei Bi, Ping Yang, George W. Kattawar, Fuzhong Weng, Quanhua Liu, Thomas Greenwald, Single-scattering properties of ice particles in the microwave regime: Temperature effect on the ice refractive index with implications in remote sensing, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 190, 2017, Pages 26-37, ISSN 0022-4073, https://doi.org/10.1016/j.jqsrt.2016.11.026.

Particle types

pristine and aggregates

Sizes

2 microns to 10 millimeters

Frequencies

1 to 886 GHz

Orientations

random

Temperatures

230 to 270 K

Scattering method

II-TM and IGOM

An ice crystal single-scattering property database is developed in the microwave spectral region (1 to 874 GHz) to provide the scattering, absorption, and polarization properties of 12 ice crystal habits (10-plate aggregate, 5-plate aggregate, 8-column aggregate, solid hexagonal column, hollow hexagonal column, hexagonal plate, solid bullet rosette, hollow bullet rosette, droxtal, oblate spheroid, prolate spheroid, and sphere) with particle maximum dimensions from 2 µm to 10 mm. For each habit, four temperatures (160, 200, 230, and 270 K) are selected to account for temperature dependence of the ice refractive index. The microphysical and scattering properties include projected area, volume, extinction efficiency, single-scattering albedoasymmetry factor, and six independent nonzero phase matrix elements (i.e. P11, P12, P22, P33, P43 and P44). The scattering properties are computed by the Invariant Imbedding T-Matrix (II-TM) method and the Improved Geometric Optics Method (IGOM). The computation results show that the temperature dependence of the ice single-scattering properties in the microwave region is significant, particularly at high frequencies. Potential active and passive remote sensing applications of the database are illustrated through radar reflectivity and radiative transfer calculations. For cloud radar applications, ignoring temperature dependence has little effect on ice water content measurements. For passive microwave remote sensing, ignoring temperature dependence may lead to brightness temperature biases up to 5 K in the case of a large ice water path.

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