The Airborne Measurement of Atmospheric Conductivity

Abstract

The simultaneous measurement of both polar conductivities from a P4Y airplane using two Gerdien‐type condensers is described. An altitude distribution of conductivity representative of clear arctic air is presented. From this distribution, a columnar resistance of 6.0×1016 ohm‐m2 is obtained by integration from the earth's surface to 6 km. The average ratio of negative to positive conductivity was found to be 1.1. The charge on the aircraft was found to have negligible effect on the conductivity measurement for fair weather conditions. Triboelectric charging of the conductivity chamber central electrodes by aerosols was observed on most fair weather flights. Concurrent observations at the earth's surface occasionally exhibited the same effect. Even in its presence, techniques were used which permitted valid measurements of conductivity to be made. It is suggested that this effect may have been responsible for unusually high positive‐to‐negative conductivity ratios reported by others.

DC Electric Field Effects During Measurements of Monopolar Charge Density and Net Space Charge Density near HVDC Power Lines

“…It is noted that similar experimental results have been obtained during conductivity measurements aboard airplanes [11,12].…”

Measurements of Atmospheric Electricity Aloft

“…Attempts to measure conductivity inside ice cloud have also been made, however this is even more difficult than measuring conductivity inside liquid water cloud, as shown by Kraakevik (1958), whose aircraft based conductivity instrument was taken off-scale in the negative direction inside a cirrus cloud. He interpreted this as negative charge flowing to the central electrode, most likely due to tribo-electric charging of the central electrode by ice crystals.…”

“…Scott and Evans (1969), or reducing the air flow rate to the tube so that no ions are deliberately collected (e.g. Kraakevik 1958). …”

Fair weather electric charge transfer by convection in an unstable planetary boundary layer

“…In the presence of the substantial vertical gradients of space charge density that can exist in the Austausch layer, and especially near the surface, there is ample opportunity for turbulence and convection to set up significant mechanical transfer currents. The first recognition of this important fact seems to be due to Kraakevik and Clark, who, in a series of papers [Clark (1957), Kraakevik (1958a), Clark (1958), Kraakevik (1958b), Kraakevik and Clark (1958), and Kraakevik (1961)], reported on measurements from an airplane of vertical profiles of conductivity A and vertical electric field E up to 6 km elevation. Profiles of X, E, and p (derived from p = eg-) for flights over dz the Greenland ice cap and over the Chesapeake Bay are presented in~figure 1.1.…”