Atmospheric Global Circuit Variations from Vostok and Concordia Electric Field Measurements

Abstract

Atmospheric electric field measurements from the Concordia station on the Antarctic Plateau are compared with those from Vostok (560 km away) for the period of overlap and to Carnegie (1915-29) and extended Vostok (2006-11) measurements. The Antarctic data are sorted according to several sets of criteria for rejecting local variability to examine a local summer-noon influence on the measurements and to improve estimates of the global signal. The contribution of the solar wind influence is evaluated and removed from the Vostok and Concordia measurements. Simultaneous measurements yield days when the covariability of the electric field measurements at Concordia and Vostok exceeds 90%, as well as intervals when significant local variability is apparent. Days of simultaneous changes in shape and mean level of the diurnal variation, as illustrated in a 5-day sequence, can be interpreted as due to changes in the relative upward current output of the electrified cloud generators predominating at low latitudes. Smaller average local meteorological influences are removed from the larger Vostok dataset, revealing changes in the shape of monthly average diurnal variations, which are similarly attributed to changes in predominantly low-latitude convection from month to month.

Toward a Realistic Representation of Global Electric Circuit Generators in Models of Atmospheric Dynamics

“…However, even after this transformation the main maximum of the simulated IP variation would be reached about 2 hr earlier than that of the Carnegie curve. What is more important, this could not explain the conspicuous difference of amplitudes corresponding to winter (NDJ and FMA) and summer (MJJ and ASO), clearly visible in the results of simulations but absent in the Carnegie data (see Figures c–f and Table ) and in the data from other measurement campaigns (e.g., Burns et al, ; Figure 8). In addition, the whole idea of simply reducing the contribution of oceans lacks thorough substantiation on the basis of precise physical criteria; note that Mach et al () found that oceanic thunderstorms and ESCs actually produce greater mean currents than their land counterparts, although, strictly speaking, it would be more natural to compare current densities rather than total currents supplied by clouds.…”

“…Adapted from Slyunyaev et al (). (c)–(f) Comparison of the simulated diurnal variations of the IP corresponding to different seasons (A, blue) with the corresponding fits to the Carnegie data given by Harrison () (B, red) and Burns et al () (C, green). In panels (a) and (b) the IP is presented as a fraction of the annual mean; in panels (c)–(f) the IP is shown as a fraction of the respective seasonal mean.…”

“…The authors are grateful to Gary Burns for providing the Fourier fits to the Carnegie data used in Burns et al (). This work was supported by the Russian Science Foundation (Project 18‐77‐10061).…”

“…In the following years measurements performed by different researchers have produced further evidence that the mean diurnal variation of the GEC is quite satisfactorily described by the classical Carnegie curve, not only for the fair‐weather electric field but also for other GEC parameters such as the IP (e.g., Harrison, ; Markson, ; Mühleisen, ). At the same time it should be noted that strictly speaking, this curve does not show an annual mean owing to the nonuniform seasonal sampling in the Carnegie data and substantial seasonal variability of the GEC (Burns et al, ).…”

A TRMM/GPM retrieval of the total mean generator current for the global electric circuit

“…These ships recorded the average fair‐weather electric field as a function of Universal Time during their voyages across the world's oceans to establish the diurnal variation of the GEC [ Whipple , ]. The resulting annual average variation given by Israel [, Appendix, Table XIX] is known as the "classic" Carnegie curve, and provides a climatology that approximates the modern measurements of the fair weather electric field in the Antarctic [ Burns et al , , , ] and the ionospheric potential [ Markson , ]. The Carnegie curve's early 20 th century origins make it a natural reference point against which to assess large‐scale changes in electrified weather with the passage of time [ Harrison , ].…”