The influence of diffusional growth rates on the charge transfer accompanying rebounding collisions between ice crystals and soft hailstones

BAKER, B; BAKER, MB; Jayaratne, E.R.; Latham, John; SAUNDERS, CPR

doi:10.1256/smsqj.47806

Cited by 86 publications

(63 citation statements)

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“…Reynolds et al (1957) and subsequent laboratory studies (Takahashi 1978;Baker et al 1987;Saunders et al 1991;Pereyra et al 2000) demonstrated the efficacy of this process and its enhancement by active riming. This process is sometimes called the relative growth rate mechanism, wherein supercooled water is thought to enhance the difference in vapor flux to two species of colliding hydrometeors.…”

Section: Thunderstorm Charge Regions and Storm Structurementioning

confidence: 91%

Formation of Charge Structures in a Supercell

Bruning

Rust

MacGorman

et al. 2010

Monthly Weather Review

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Lightning mapping, electric field, and radar data from the 26 May 2004 supercell in central Oklahoma are used to examine the storm's charge structure. An initial arc-shaped maximum in lightning activity on the right flank of the storm's bounded weak echo region was composed of an elevated normal polarity tripole in the region of precipitation lofted above the storm's weak echo region. Later in the storm, two charge structures were associated with precipitation that reached the ground. To the left of the weak echo region, six charge regions were inferred, with positive charge carried on hail at the bottom of the stack. Farther forward in the storm's precipitation region, four charge regions were inferred, with negative charge at the bottom of the stack. There were different charge structures in adjacent regions of the storm at the same time, and regions of opposite polarity charge were horizontally adjacent at the same altitude. Flashes occasionally lowered positive charge to ground from the forward charge region. A conceptual model is presented that ties charge structure in different regions of the storm to storm structure inferred from radar reflectivity. Thunderstorm charge regions and storm structureThis study is concerned with the ability to predict charge regions, associated lighting, and their evolution in time by examining several radar reflectivity cross sections through a supercell. More generally, it tests the expected relationship between precipitation formation and arrangement within the storm as indicated by radar reflectivity and the formation of local cellular maxima in total lightning activity. To facilitate the analysis, it is useful to adopt some terminology from previous radar analyses of supercells.Precipitation forms in thunderstorm updrafts and falls out where the hydrometeor terminal fall speed is not compensated by an updraft (Byers and Braham 1949). Both updrafts and downdrafts persist simultaneously in quasi-steady-state supercells. The strongest surface convergence is typically near the right-rear flank of the storm where forward flank downdrafts (FFDs) and rear flank downdrafts (RFDs) both impinge on boundary layer flow to sustain a concentrated, rotating updraft (Lemon and Doswell 1979). (Throughout this study, the terms forward, rear, left, and right are oriented relative

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Section: Thunderstorm Charge Regions and Storm Structurementioning

confidence: 91%

Formation of Charge Structures in a Supercell

Bruning

Rust

MacGorman

et al. 2010

Monthly Weather Review

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“…The actual charge transfer mechanism includes the relative diffusion growth rate of the riming surface between graupel and ice crystal (Baker et al, 1987;Jayaratne et al, 1983). Brooks et al (1997) indicated that charge transfer is a function of the rime accretion rate (RAR) and the size and velocity of ice crystals.…”

Section: Representation Of Electrificationmentioning

confidence: 99%

“…10b). The laboratory study of Saunders et al (1991) indicated that high effective liquid water content in the low temperature zone leads to graupel charge positively, and Baker et al (1987) showed that graupel particle capturing liquid water freezing on the surface, leads to carrying positive charge. RAR related to cloud water content is the crucial factor of ice particles charging polarity, therefore the enhancing cloud water content in P-CASE is the main reason for formation of the negative charge region above the main positive charge center.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Numerous microphysical characteristics affect the polarity and magnitude of the electrification processes of thunderstorm. Baker et al (1987) proposed the Relative Diffusional Growth Rate theory to explain charge transferring mechanisms, and indicated that ice particles with greater surface growth rates would charge positively during collision separation processes. The growth rate of ice crystals is inversely proportional to the particle size, hence the charging positively temperature range of graupel collided and separated with larger ice crystal increases (Emersic and Saunders, 2010).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effects of aerosol on development of thunderstorm electrification: A numerical study

Zhao

Yin

Xiao

2015

Atmospheric Research

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“…Latham, 1981) to show that the dominant charging mechanism in most thunderstorms is the non-inductive process (Reynolds et al (1957); Takahashi (1978); Jayaratne et al (1983); Baker et al (1987) Norville et al (1991), Miller et al (2001), and a series of papers describing laboratory experiments by Saunders and colleagues at UMIST), which involves rebounding collisions between growing graupel pellets and ice crystals. The separation of electric charge is restricted to the charging zone, which is the region of the thundercloud within which coexist the hydrometeors (graupel pellets, ice crystals and supercooled water droplets), vital to the operation of the charging process.…”

Section: Estimation Of Precipitation Rates and Yields From Lightning mentioning

confidence: 99%