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  • A Polarimetric Radar Analysis of Ice Microphysical Processes in Melting Layers of Winter Storms Using S-Band Quasi-Vertical Profiles
Title: A Polarimetric Radar Analysis of Ice Microphysical Processes in Melting Layers of Winter Storms Using S-Band Quasi-Vertical Profiles

Quasi-vertical profiles (QVPs) obtained from a database of U.S. WSR-88D data are used to document polarimetric characteristics of the melting layer (ML) in cold-season storms with high vertical resolution and accuracy. A polarimetric technique to define the top and bottom of the ML is first introduced. Using the QVPs, statistical relationships are developed to gain insight into the evolution of microphysical processes above, within, and below the ML, leading to a statistical polarimetric model of the ML that reveals characteristics that reflectivity data alone are not able to provide, particularly in regions of weak reflectivity factor at horizontal polarization ZH. QVP ML statistics are examined for two regimes in the ML data: ZH≥ 20 dB Z and ZH< 20 dB Z. Regions of ZH≥ 20 dB Z indicate locations of MLs collocated with enhanced differential reflectivity ZDRand reduced copolar correlation coefficient ρhv, while for ZH< 20 dB Z a well-defined ML is difficult to discern using ZHalone. Evidence of large ZDRup to 4 dB, backscatter differential phase δ up to 8°, and low ρhvdown to 0.80 associated with lower ZH(from −10 to 20 dB Z) in the ML is observed when pristine, nonaggregated ice falls through it. Positive correlation is documented between maximum specific differential phase KDPand maximum ZHin the ML; these are the first QVP observations of KDPin MLs documented at S band. Negative correlation occurs between minimum ρhvin the ML and ML depth and between minimum ρhvin the ML and the corresponding enhancement of ZH(Δ ZH= ZHmax− ZHrain).

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Award ID(s):
1841246
NSF-PAR ID:
10146264
Author(s) / Creator(s):
 ;  ;  
Publisher / Repository:
American Meteorological Society
Date Published:
Journal Name:
Journal of Applied Meteorology and Climatology
Volume:
59
Issue:
4
ISSN:
1558-8424
Page Range / eLocation ID:
p. 751-767
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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