Aircraft measurements of the atmospheric electrical global circuit during the period 1971–1984

Abstract

This report will update an investigation of the global circuit conducted over the last 14 years through aircraft measurements of the variation of ionospheric potential and associated parameters. The data base included electric field, conductivity, and air‐earth current density profiles from the tropics (25°N) to the Arctic (79°N). Almost all of the data have been obtained over the ocean to reduce noise associated with local generators, aerosols, and convection. Recently, two aircraft have been utilized to obtain, for the first time, quasi‐periodic sets of simultaneous ionospheric potential (VI) soundings at remoted locations and extending over time spans sufficiently long so that the universal time diurnal variation (Carnegie curve) could be observed. In addition, these measurements provided the first detection of the modulation of electric fields in the troposphere caused by the double vortex ionospheric convection pattern. Beside summarizing these measurements and comparing them to similar data obtained by other groups, this report will discuss meteorological sources of error and criteria for determining if the global circuit is being measured rather than variations caused by local meteorological processes.

The Global Atmospheric Electrical Circuit and Climate

“…Many intermittent measurements of V I exist from the late 1950s (Imyanitov and Chubarina, 1967;Markson, 1976Markson, , 1985. Those of Mülheisen (Budyko, 1971) obtained in Germany between 1959 and 1972 are notable for providing important support for the global circuit concept from the common simultaneous variations in V I found at different locations (Mülheisen, 1971).…”

NOx from lightning: 2. Constraints from the global atmospheric electric circuit

“…The equivalent electric circuit is shown in Figure lb, where global thunderstorms represent the battery in the circuit. To prove that this atmospheric electric circuit is truly global, measurements of the air-Earth current and the potential gradient at the Earth's surface have been made simultaneously at different locations around the globe, and the agreement with each other is quite remarkable [Muhleisen, 1971;Markson, 1985].…”

Twentieth century secular decrease in the atmospheric potential gradient

“…Direct measurements began in 1956, with a decrease in V I reported [Markson, 1976] Figure 2a). Figure 2d shows the V I values [Markson, 1985], from soundings corrected using the Carnegie diurnal variation. The 1961-64 anomalies are plotted as triangles.…”

“…(c) Variations of the cosmogenic isotope Be-10 deposited in the Greenland ice core [Beer, 2000]. (d) Ionospheric potential measurements [Markson, 1985], (squares and triangles) with a trend line estimated. The trend line has been fitted to selected 1956-1970 measurements (squares).…”