The relationship between lightning activity and ice fluxes in thunderstorms

Abstract

[1] It is generally believed that a strong updraft in the mixed-phase region of thunderstorms is required to produce lightning. This is the region where the noninductive charging process is thought to generate most of the storm electrification. Analytic calculations and model results predict that the total lightning frequency is roughly proportional to the product of the downward mass flux of solid precipitation (graupel) and the upward mass flux of ice crystals. Thus far this flux hypothesis has only been tested in a very limited way. Herein we use dual-polarimetric and dual-Doppler radar observations in conjunction with total lightning data collected in Northern Alabama and also Colorado/ Kansas during two field campaigns. These data are utilized to investigate total lightning activity as a function of precipitation and nonprecipitation ice masses and estimates of their fluxes for different storm types in different climate regions. A total of 11 storms, including single cell, multicell, and supercell storms, was analyzed in the two climatologically different regions. Time series of both precipitation and nonprecipitation ice mass estimates above the melting level show a good relationship with total lightning activity for the 11 storms analyzed (correlation coefficients exceed 0.9 and 0.8, respectively). Furthermore, the relationships are relatively invariant between the two climate regions. The correlations between total lightning and the associated product of ice mass fluxes are even higher. These observations provide strong support for the flux hypothesis.

Using cloud ice flux to parametrise large-scale lightning

“…Improved representation of cloud ice in models now allows the implementation of another aspect of the theory, the upward flux of ice crystals. Deierling et al (2008) have shown that the upward ice flux displays a strong linear correlation with lightning flashes in 11 observed US storms.…”

“…The result is net accumulation of opposite charge in different parts of the thundercloud. This has been shown to be a realistic theory through a combination of laboratory, field measurement and satellite studies (Williams, 1989;Blyth et al, 2001;Petersen et al, 2005;Saunders, 2008;Deierling et al, 2008;Liu et al, 2012).…”

“…On the contrary, the ICEFLUX parametrisation shows the greatest delay bias although the lowest absolute bias. This suggests it could be an issue with the input meteorology or the need for an extension of the model to include a graupel flux, as in Deierling et al (2008), to fully account for the seasonal cycle. Cloud resolving models would provide an appropriate means of testing the importance of graupel and other features of ice-based parametrisations as they include more explicit representations of cloud parameters.…”

Total Lightning Flash Activity Response to Aerosol over China Area

“…Lightning intensity was closely linked with convection intensity. The strong updraft, a deep ice water mixing region, and large ice particles' flux may enhance lightning activities of a thunderstorm [6][7][8]. The intimate connection between electrical activity and some factors in the mixed-phase region was mainly due to the non-inductive charging process where rebounding collisions between big and small ice particles lead to appreciable charge separation.…”

Effect of bacterial ice nuclei on the frequency and intensity of lightning activity inferred by the BRAMS model

“…Petersen et al (2005) found a linear relationship between total lightning flash rate and ice water path, independent of the regime (land, ocean or coastal zones). Likewise, based on the charging zone concept, several studies have shown strong correlation between the total (intra-cloud and cloudto-ground lightning) flash rate and the precipitable and nonprecipitable ice masses (Blyth et al, 2001;Latham et al, 2004Latham et al, , 2007Deierling et al, 2008). The terms precipitable and non-precipitable ice masses are associated with the hydrometeor types likely to precipitate or not, relative to the convective core updraft, i.e., denser particles like hail and graupel can precipitate over the convective core and are defined as precipitable ice mass, while snowflakes and ice crystals cannot and are therefore defined as non-precipitable ice mass.…”