Time-varying ice crystal orientation in thunderstorms observed with multiparameter radar

Caylor, I. J.; Chandrasekar, V.

doi:10.1109/36.508402

Cited by 65 publications

(56 citation statements)

References 28 publications

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“…This supposition was confirmed mainly by polarized radar observations (Mendez, 1969;Hendry and McCormick, 1976;Krehbiel et al, 1996) and theoretical modelling (Weinheimer and Few, 1987). The occurrence of vertical alignment is well correlated with lightning activity (Prigent et al, 2005) -for a review see Caylor and Chandrasekar (1996). The process we are reporting is similar, except that it involves smaller particles and electric fields some two orders of magnitude weaker.…”

Section: Discussionsupporting

confidence: 58%

Alignment of atmospheric mineral dust due to electric field

et al. 2007

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Abstract. Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction indicating the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV/m. Two alternative mechanisms for the origin of the field are examined: the effect of reduced atmospheric conductivity and charging of the dust layer, the latter effect being a more likely candidate. It is concluded that partial alignment may be a common feature of Saharan dust layers. The modelling indicates that the alignment can significantly alter dust optical depth. This "Venetian blind effect" may have decreased optical thickness in the vertical direction by as much as 10% for the case reported here. It is also possible that the alignment and the electric field modify dust transport.

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Section: Discussionsupporting

confidence: 58%

Alignment of atmospheric mineral dust due to electric field

et al. 2007

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“…Now in print, this work is one addition to a large collection of published studies on polarimetric radar measurements (Jameson et al 1996;Caylor and Chandrasekhar 1996;Krehbiel et al 1996, Metcalf 1993Kennedy and Rutledge 2011;Andric et al 2013;Bechini et al 2013) with microphysical interpretations but without in situ validations.…”

Section: Introductionmentioning

confidence: 99%

Measurements of Differential Reflectivity in Snowstorms and Warm Season Stratiform Systems

Williams

Smalley

Donovan

et al. 2015

Journal of Applied Meteorology and Climatology

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The organized behavior of differential radar reflectivity (ZDR) is documented in the cold regions of a wide variety of stratiform precipitation types occurring in both winter and summer. The radar targets and attendant cloud microphysical conditions are interpreted within the context of measurements of ice crystal types in laboratory diffusion chambers in which humidity and temperature are both stringently controlled. The overriding operational interest here is in the identification of regions prone to icing hazards with long horizontal paths. Two predominant regimes are identified: category A, which is typified by moderate reflectivity (from 10 to 30 dBZ) and modest 1ZDR values (from 0 to 13 dB) in which both supercooled water and dendritic ice crystals (and oriented aggregates of ice crystals) are present at a mean temperature of 2138C, and category B, which is typified by small reflectivity (from 210 to 110 dBZ) and the largest 1ZDR values (from 13 to 17 dB), in which supercooled water is dilute or absent and both flat-plate and dendritic crystals are likely. The predominant positive values for ZDR in many case studies suggest that the role of an electric field on ice particle orientation is small in comparison with gravity. The absence of robust 1ZDR signatures in the trailing stratiform regions of vigorous summer squall lines may be due both to the infusion of noncrystalline ice particles (i.e., graupel and rimed aggregates) from the leading deep convection and to the effects of the stronger electric fields expected in these situations. These polarimetric measurements and their interpretations underscore the need for the accurate calibration of ZDR.

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“…Ice particles tend to be oriented with the electric field and that can produce negative values of Z DR , especially at the upper part of the thunderstorm, given the vertical alignment of irregular ice particles. So, Z DR might be used as an indicator of potential lightning strikes (Caylor and Chandrasekar, 1996).…”

Section: Discussionmentioning

confidence: 99%

A mobile X-POL weather radar for hydrometeorological applications in the metropolitan area of São Paulo, Brazil

Filho¹

2012

Geosci. Instrum. Method. Data Syst.

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Abstract. This paper presents the first mobile X-band dualpolarization Doppler weather radar termed MXPOL operated by the Laboratory of Hydrometeorology (LABHIDRO) of the University of São Paulo, São Paulo, Brazil. It is used in graduate and under graduate courses, real-time monitoring and nowcasting of severe weather in the Metropolitan Area of São Paulo (MASP). It is one of the first of its kind to be used operationally to provide real-time high spatial resolution polarimetric data. MXPOL is an important component of a Hydrometeorological Forecast System (Pereira Filho et al., 2005) for MASP. This manuscript presents some instances of MXPOL polarimetric measurements of weather systems and their respective microphysical, dynamical and boundary layer features that can improve nowcasting.

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Time-varying ice crystal orientation in thunderstorms observed with multiparameter radar

Cited by 65 publications

References 28 publications

Alignment of atmospheric mineral dust due to electric field

Alignment of atmospheric mineral dust due to electric field

Measurements of Differential Reflectivity in Snowstorms and Warm Season Stratiform Systems

A mobile X-POL weather radar for hydrometeorological applications in the metropolitan area of São Paulo, Brazil

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