Universal diurnal variations in air‐Earth current density

An analysis is presented that specifies conditions necessary to the procurement of atmospheric electric data that are validly representative of global conditions. Two bodies of data taken under such idealized conditions are given. Good qualitative agreement is observed to exist between measurements made over the Mediterranean and Tasman seas in that the maxima at 1000 and 1900 GMT are observed in both sets of current density data. It is further seen that the quantitative differences between the curves are in a direction indicating a tendency to accentuate the effect of storm activity co-hemispheric with the measuring site and to attenuate the effects of far distant storms. Data taken on a round trip transit between Washington, D.C., and Australia are shown to be in substantial agreement with data taken in idealized circumstances. It is concluded that an average ‘global’ curve is a bimodal curve of the type shown but that, since regional effects appear to be significant, it is quite unlikely that this exact curve would ever be exactly duplicated.