Altitude, thickness and charge concentration of charged regions of four thunderstorms during trip 1981 based upon in situ balloon electric field measurements

Abstract

Balloon borne corona probes designed to measure vertical electric fields have yielded data on the vertical electric structure of four thunderstorms studied during the Thunderstorm Research International Program (TRIP), 1981. All four thunderclouds exhibited a bipolar charge structure with an upper positive charge region and a lower negative charge region. The negative region was consistently centered between the 0° C and −10° C isotherm altitudes. The altitudes of the concentrated positive regions varied considerably. The average vertical extent of the negative regions was 1 km with estimated average charge concentrations ranging from −.7 nC/m³ to −1.8 nC/m³. The average thickness of the positive regions was 1.5 km with estimated charge concentrations averaging .5 nC/M³ to 1.7 nC/m³.

Measurements of Atmospheric Electricity Aloft

“…Flights through 4 thunderstorms showed a bipolar charge structure with a lower negative charge region, and upper positive charge region. The negative charge region was consistently located between 0 and -10°C, with a vertical depth of ≈1km, and average charge densities from -0.7 to -1.8 nCm In contrast to the bipolar charge structure measured by Byrne et al (1983), Marshall and Rust (1991) found that from 12 profiles through thunderstorms there were typically between 4 and 10 distinct charge layers, of vertical depth 130m to 2100m, with charges ranging from 0.2 to 13 nCm . Measurements of electric field were made from a balloon platform, using the EFM.…”

“…This instrument measures the corona-point discharge current induced through a conducting wire by the electric field, and is described by Weber and Few (1978), and Weber et al (1983). Flights through 4 thunderstorms showed a bipolar charge structure with a lower negative charge region, and upper positive charge region.…”

“…This technique has been widely used for electric field measurement in thunderstorms from a free balloon platform (e.g. Byrne et al 1983Byrne et al , 1987Byrne et al , 1989, however, careful interpretation of measurements is required due to corona current dependency on pressure, temperature, wind speed and water vapour.…”

“…A different technique to electric field meters was implemented by Byrne et al (1983) using a corona probe (see section 3.1.1). This instrument measures the corona-point discharge current induced through a conducting wire by the electric field, and is described by Weber and Few (1978), and Weber et al (1983).…”

Vertical Electric Fields and Field Change Parameters Due to Partly Inclined Lightning Leader Channels

“…This characteristic of leader and return stroke fields (static fields) provides information to estimate the charge source heights. Taking measurements by balloon-borne instruments is also a popular method [27][28][29][30]. In some cases more than one of these techniques are applied to obtain more precise information.…”