A comparison of X-band polarization parameters with in situ microphysical measurements in the comma head of two winter cyclones

Joseph A. Finlon, Greg Michael McFarquhar, Robert M Rauber, David M. Plummera, Brian F. Jewett, David Leon, Kevin R. Knupp

Research output: Contribution to journalArticle

Abstract

Since the advent of dual-polarization radar, methods of classifying hydrometeors by type from measured polarization variables have been developed. The deterministic approach of existing hydrometeor classification algorithms of assigning only one dominant habit to each radar sample volume does not properly consider the distribution of habits present in that volume, however. During the Profiling of Winter Storms field campaign, the "NSF/NCAR C-130" aircraft, equipped with in situ microphysical probes, made multiple passes through the comma heads of two cyclones as the Mobile Alabama X-band dual-polarization radar performed range-height indicator scans in the same plane as the C-130 flight track. On 14-15 February and 21-22 February 2010, 579 and 202 coincident data points, respectively, were identified when the plane was within 10 s (~1 km) of a radar gate. For all particles that occurred for times within different binned intervals of radar reflectivity ZHH and of differential reflectivity ZDR, the reflectivity-weighted contribution of each habit and the frequency distributions of axis ratio and sphericity were determined. This permitted the determination of habits that dominate particular ZHH and ZDR intervals; only 40% of the ZHH-ZDR bins were found to have a habit that contributes over 50% to the reflectivity in that bin. Of these bins, only 12% had a habit that contributes over 75% to the reflectivity. These findings show the general lack of dominance of a given habit for a particular ZHH and ZDR and suggest that determining the probability of specific habits in radar volumes may be more suitable than the deterministic methods currently used.

Original languageEnglish (US)
Pages (from-to)2549-2574
Number of pages26
JournalJournal of Applied Meteorology and Climatology
Volume55
Issue number12
DOIs
StatePublished - Jan 1 2016

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cyclone
in situ measurement
polarization
reflectivity
radar
winter
parameter
comparison
aircraft
flight
probe
distribution
method

Keywords

  • Cloud microphysics
  • Ice particles
  • Radars/radar observations
  • Winter/cool season

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

A comparison of X-band polarization parameters with in situ microphysical measurements in the comma head of two winter cyclones. / Finlon, Joseph A.; McFarquhar, Greg Michael; Rauber, Robert M; Plummera, David M.; Jewett, Brian F.; Leon, David; Knupp, Kevin R.

In: Journal of Applied Meteorology and Climatology, Vol. 55, No. 12, 01.01.2016, p. 2549-2574.

Research output: Contribution to journalArticle

Finlon, Joseph A. ; McFarquhar, Greg Michael ; Rauber, Robert M ; Plummera, David M. ; Jewett, Brian F. ; Leon, David ; Knupp, Kevin R. / A comparison of X-band polarization parameters with in situ microphysical measurements in the comma head of two winter cyclones. In: Journal of Applied Meteorology and Climatology. 2016 ; Vol. 55, No. 12. pp. 2549-2574.
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