The 94-GHz radar dim band: Relevance to ice cloud properties and cloudsat

AMS Citation:
Heymsfield, A. J., A. R. Bansemer, S. Matrosov, and L. Tian, 2008: The 94-GHz radar dim band: Relevance to ice cloud properties and cloudsat. Geophysical Research Letters, 35, L03802 L03802, doi:10.1029/2007GL03136.
Date:2008-02-01
Resource Type:article
Title:The 94-GHz radar dim band: Relevance to ice cloud properties and cloudsat
Abstract: Details of the microphysics are shown to be responsible for a region of ice cloud which, when probed from above, has decreasing radar reflectivity (Ze ) downwards at 94 GHz but increasing Z e at 9.7 GHz. This 94-GHz radar dim band is found to be due to the combination of ice particle aggregation and non-Rayleigh scattering effects. Observations and model calculations indicate that it occurs when the particle size distribution (PSD) broadens such that its slope, as derived from fitted PSD, decreases below about 15 cm⁻¹, or equivalently, to a median volume diameter exceeding 0.25 cm. Dimming occurs at temperatures (T) primarily between −5 and 0°C but can occur at −30°C or below in convectively-generated ice clouds (anvils). The dimming effect may produce an appreciable low bias in the ice water content (IWC) retrieved from Z measured by CloudSat's 94-GHz radar. Methods to estimate the IWC in the dim band are proposed.
Subject(s):94-GHz radar dim band, CloudSat
Peer Review:Refereed
Copyright Information:An edited version of this paper was published by AGU. Copyright 2008 American Geophysical Union.
OpenSky citable URL: ark:/85065/d7gq6xx8
Publisher's Version: 10.1029/2007GL03136
Author(s):
  • Andrew Heymsfield - NCAR/UCAR
  • Aaron Bansemer - NCAR/UCAR
  • Sergey Matrosov
  • Lin Tian
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