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  • Estimating Ice Water Content for Winter Storms from Millimeter-Wavelength Radar Measurements Using a Synthesis of Polarimetric and Dual-Frequency Radar Observations
Title: Estimating Ice Water Content for Winter Storms from Millimeter-Wavelength Radar Measurements Using a Synthesis of Polarimetric and Dual-Frequency Radar Observations
Abstract The potential of millimeter-wavelength radar-based ice water content (IWC) estimation is demonstrated using a Ka-band Scanning Polarimetric Radar (KASPR) for the U.S. northeast coast winter storms. Two IWC relations for Ka-band polarimetric radar measurements are proposed: one that uses a combination of the radar reflectivityZand the estimated total number concentration of snow particlesNtand the other based on the joint use ofZ, specific differential phaseKDP, and the degree of rimingfrim. A key element of the algorithms is to obtain the “Rayleigh-equivalent” value ofZmeasured at the Ka band, i.e., the correspondingZat a longer radar wavelength for which Rayleigh scattering takes place. This is achieved via polarimetric retrieval of the mean volume diameterDmand incorporating the relationship between the dual-wavelength ratio DWRS/KaandDm. Those techniques allow for retrievals from single millimeter-wavelength radar measurements and do not necessarily require the dual-wavelength ratio (DWR) measurements, if the DWR–Dmrelation and Rayleigh assumption for Ka-bandKDPare valid. Comparison between the quasivertical profile product obtained from KASPR and the columnar vertical profile product generated from the nearby WSR-88D S-band radar measurements demonstrates that the DWRS/Kacan be estimated from the two close radars without the need for collocated radar beams and synchronized antenna scanning and can be used for determining the Rayleigh-equivalent value ofZ. The performance of the suggested techniques is evaluated for seven winter storms using surface disdrometer and snow accumulation measurements. Significance StatementIce water content (IWC) estimation using millimeter-wavelength radar measurements has been challenging for decades, because of the complexity of snow particle properties and size, which can cause complex scattering at the shorter radar wavelengths. The suggested polarimetric techniques overcome this difficulty via utilizing specific differential phaseKDPwhich is higher at millimeter wavelengths than at centimeter wavelengths. This study proposes new IWC relationships for Ka-band polarimetric radar measurements and evaluates them using a Ka-band Scanning Polarimetric Radar (KASPR) and a nearby NEXRAD (S-band) polarimetric radar for the U.S. northeast coast winter storms. The proposed techniques can be applied to other millimeter-wavelength radars and shed light on the millimeter-wavelength polarimetric radar IWC estimation.  more » « less
Award ID(s):
2113070
PAR ID:
10625322
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
American Meteorological Society
Date Published:
Journal Name:
Journal of Atmospheric and Oceanic Technology
Volume:
42
Issue:
1
ISSN:
0739-0572
Page Range / eLocation ID:
75 to 90
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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