TY - JOUR

T1 - First ground-based observations of sprites over southern Africa

AU - Nnadih, S.

AU - Kosch, M.

AU - Martinez, P.

AU - Bor, J.

PY - 2018/9/11

Y1 - 2018/9/11

N2 - Sprites are the optical signatures of electrical discharges in the mesosphere triggered by large lightning strikes associated with thunderstorms. Since their discovery in the late 1980s, sprites have been observed extensively around the world, although very few observations of sprites from Africa have been documented in the literature. In this paper, we report the first ground-based recorded observations of sprites from South Africa. In 2 out of the 22 nights of observations (11 January and 2 February 2016), about 100 sprite elements were recorded from Sutherland in the Northern Cape, comprising different morphologies (carrot (55%), carrot/column (11%), unclassified (21%), column (13%)). The sprites were triggered by positive cloud-to-ground lightning strikes, which had an average peak value of ~74 kA and were observed at distances from ~400 km to 800 km. The estimated charge moment change of the lightning discharges associated with these events was in agreement with the threshold for dielectric breakdown of the mesosphere and correlates well with the observed sprite brightness. Significance: • The first ground-based recording of sprite events over southern Africa. • It is suggested that the intensity of the events is proportional to the lightning stroke current. © 2018. The Author(s). Published under a Creative Commons Attribution Licence.

AB - Sprites are the optical signatures of electrical discharges in the mesosphere triggered by large lightning strikes associated with thunderstorms. Since their discovery in the late 1980s, sprites have been observed extensively around the world, although very few observations of sprites from Africa have been documented in the literature. In this paper, we report the first ground-based recorded observations of sprites from South Africa. In 2 out of the 22 nights of observations (11 January and 2 February 2016), about 100 sprite elements were recorded from Sutherland in the Northern Cape, comprising different morphologies (carrot (55%), carrot/column (11%), unclassified (21%), column (13%)). The sprites were triggered by positive cloud-to-ground lightning strikes, which had an average peak value of ~74 kA and were observed at distances from ~400 km to 800 km. The estimated charge moment change of the lightning discharges associated with these events was in agreement with the threshold for dielectric breakdown of the mesosphere and correlates well with the observed sprite brightness. Significance: • The first ground-based recording of sprite events over southern Africa. • It is suggested that the intensity of the events is proportional to the lightning stroke current. © 2018. The Author(s). Published under a Creative Commons Attribution Licence.

KW - Atmosphere

KW - Lightning discharge

KW - Mesosphere

KW - Thunderstorm

KW - atmospheric electricity

KW - cloud to ground lightning

KW - dielectric property

KW - ground-based measurement

KW - lightning

KW - mesosphere

KW - observational method

KW - sprite

KW - threshold

KW - thunderstorm

KW - Northern Cape

KW - South Africa

KW - Daucus carota

U2 - 10.17159/sajs.2018/4272

DO - 10.17159/sajs.2018/4272

M3 - Journal article

VL - 114

JO - South African Journal of Science

JF - South African Journal of Science

SN - 1996-7489

IS - 9-10

M1 - 4272

ER -