Radar observations of the alignment of precipitation particles by electrostatic fields in thunderstorms

Hendry, A.W.; McCormick, G.

doi:10.1029/jc081i030p05353

Cited by 76 publications

(34 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Vonnegut (1965) provided an explanation for abrupt changes observed in the visual appearance of the tops of thunderstorm clouds by proposing that ice crystals were being aligned along the electric field. 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).…”

Section: Discussionsupporting

confidence: 51%

See 1 more Smart Citation

Alignment of atmospheric mineral dust due to electric field

et al. 2007

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionsupporting

confidence: 51%

“…1969; Hendry and McCormick, 1976;Krehbiel et al, 1996;Prigent et al, 2005, Weinheimer andFew, 1987). We therefore examine whether atmospheric electric fields not associated with storm clouds can produce vertical alignment of mineral dust aerosols, and if such alignment can account for the polarimetric observations.…”

Section: Introductionmentioning

confidence: 99%

Alignment of atmospheric mineral dust due to electric field

et al. 2007

View full text Add to dashboard Cite

show abstract

“…Therefore, we use the equilibrium shape in (1) in this study. We also assume that the mean and the standard deviation (SD) of the canting angle are 0°, as suggested by observations (Hendry and McCormick 1976), although some observational and theoretical studies suggest that the standard deviation of the canting angles of rain drops is likely not 0°but less than 10° (Beard and Jameson 1983;Bringi and Chandrasekar 2001;Ryzhkov et al 2002). Assuming 0°SD can lead to the overestimation of K DP and Z DR by less than 6%, this could be tolerated considering the large uncertainties in DSD (Ryzhkov et al 2002).…”

Section: ϫ4mentioning

confidence: 99%

Assimilation of Simulated Polarimetric Radar Data for a Convective Storm Using the Ensemble Kalman Filter. Part I: Observation Operators for Reflectivity and Polarimetric Variables

Jung

Zhang

Xue

2008

Monthly Weather Review

146

162

View full text Add to dashboard Cite

A radar simulator for polarimetric radar variables, including reflectivities at horizontal and vertical polarizations, the differential reflectivity, and the specific differential phase, has been developed. This simulator serves as a test bed for developing and testing forward observation operators of polarimetric radar variables that are needed when directly assimilating these variables into storm-scale numerical weather prediction (NWP) models, using either variational or ensemble-based assimilation methods. The simulator takes as input the results of high-resolution NWP model simulations with ice microphysics and produces simulated polarimetric radar data that may also contain simulated errors. It is developed based on calculations of electromagnetic wave propagation and scattering at the S band of wavelength 10.7 cm in a hydrometeor-containing atmosphere. The T-matrix method is used for the scattering calculation of raindrops and the Rayleigh scattering approximation is applied to snow and hail particles. The polarimetric variables are expressed as functions of the hydrometeor mixing ratios as well as their corresponding drop size distribution parameters and densities. The presence of wet snow and wet hail in the melting layer is accounted for by using a new, relatively simple melting model that defines the water fraction in the melting snow or hail. The effect of varying density due to the melting snow or hail is also included. Vertical cross sections and profiles of the polarimetric variables for a simulated mature multicellular squall-line system and a supercell storm show that polarimetric signatures of the bright band in the stratiform region and those associated with deep convection are well captured by the simulator.

show abstract

“…Large regions near the tops of thunderstorms containing oriented crystals were observed, whose orientation abruptly changed at the time of lightning [6].…”

mentioning

confidence: 99%

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

Caylor

Chandrasekar

1996

IEEE Trans. Geosci. Remote Sensing

View full text Add to dashboard Cite

Abstract-Repeated changes associated with lightning have been observed with multiparameter radar in the echoes from the tops of Florida thunderstorms. These lightning-related radar signatures are interpreted as changes in the orientation of ice crystals being preferentially aligned parallel to the in-cloud electric field. The changes occur at intervals on the order of 10 s and are easily observed in the signatures of the differential propagation phase shift and the linear depolarization ratio which are sensitive to propagation effects caused by the oriented ice crystals. Orientation of ice crystals aloft has been previously observed using circularly polarized radar while the simultaneous differential phase shift and linear depolarization measurements reported here were obtained with a dual-linear polarized radar. The observations indicate crystal orientation angles greater than 45" and occasionally near vertical. In one case, the crystals were found to be oriented in a layer near radar cloud top spanning a 20-km range and 3 km in depth.

show abstract

Radar observations of the alignment of precipitation particles by electrostatic fields in thunderstorms

Cited by 76 publications

References 5 publications

Alignment of atmospheric mineral dust due to electric field

Alignment of atmospheric mineral dust due to electric field

Assimilation of Simulated Polarimetric Radar Data for a Convective Storm Using the Ensemble Kalman Filter. Part I: Observation Operators for Reflectivity and Polarimetric Variables

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

Contact Info

Product

Resources

About