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D region electron profiles observed with substantial spatial and temporal change near thunderstorms
Author(s) -
Lay Erin H.,
Shao XuanMin,
Jacobson Abram R.
Publication year - 2014
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2013ja019430
Subject(s) - thunderstorm , daytime , lightning (connector) , standard deviation , ionosphere , atmospheric sciences , altitude (triangle) , environmental science , electron , meteorology , physics , geophysics , mathematics , power (physics) , statistics , geometry , quantum mechanics
Abstract Broadband lightning signals are used to probe the D region ionosphere with a temporal resolution of 5 min and a spatial resolution of ~50 × 50 km. Together with a full wave propagation model, this technique allows determination of the reference height, h′ , and steepness parameter, β , of an exponential electron density profile sensitive to the range of 10 6 –10 8 electrons/m 3 . Daytime and nighttime background electron profiles away from thunderstorms are presented, as well as profiles from three regions nearby and atop thunderstorms. The average daytime profile parameters are found to be h′ = 67.7 km with a standard deviation of 0.9 km and β = 0.7 km −1 with a standard deviation of 0.1 km −1 . Average nighttime parameters are h′ = 80.9 km with a standard deviation of 1.3 km and β = 2.8 km −1 with a standard deviation of 0.2 km −1 . Nighttime electron profiles nearby and atop thunderstorms show slightly higher values of h′ (82.5–84.2 km) and significantly lower values of β (0.9–1.5 km −1 ). These findings indicate that there is significant electron depletion above ~80 km near and atop thunderstorms during the nighttime. Detailed analysis also shows substantial profile variations in space and time related to lightning discharges due to localized electron enhancement at high altitudes and reduction at lower altitudes. Nevertheless, the general depletion at higher altitudes appears to be related to the overall electrical behavior of the thunderstorm but not directly to lightning activity.