Journal of geomagnetism and geoelectricity

The results of balloon measurements of electrical conductivity and ion pair production rate obtained from the Atmospheric Electrical Measurements Workshop at the University of Wyoming in the summer of 1978 are presented. Reasonable agreement was obtained from the comparison flights of electrical conductivity. The small difference in the comparative measurements of ion pair production rate was found at stratospheric heights. The profiles of ion pair production rate measured during the period of different sunspot numbers showed a marked dependence of ion pair production rate on solar activity. The height variation of the effective ion-ion recombination coefficient calculated from the measured ion pair production rate and positive polar conductivity agrees reasonably well with the presently accepted theoretical concepts. The crossover from three-body to two-body recombination occurs at an altitude of around 23km.

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Unusually large amplitudes of the Z component of short-period geomagnetic variation have often been observed at coastal areas. In most cases, this type of anomaly is associated with an irregular shape of coastline particularly like a peninsula-like jut. In this sense the anomaly may be called the peninsula effect. The difference between the coast and peninsula effects arises from local perturbation of induced electric currents flowing in a conducting sea due to the presence of a less conducting peninsula.
A method is put forward to estimate numerically such perturbation. Basically it is a combination of numerical methods used for the coast and island effects. This method is then applied to the peninsula effects observed in the Izu and Kii Peninsulas, central Japan. It is pointed out as a conclusion that a study of peninsula effect is useful in increasing the resolution of the electrical conductivity structure beneath coastal areas.

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