REMARKABLE SOLAR-CYCLE AND SEASONAL DEPENDENCE OF THE DIURNAL GEOMAGNETIC D-VARIATIONS AT EQUATORIAL ELECTROJET STATION, KODAIKANAL

Concurrent with the midday maximum of horizontal geomagnetic field, H, the eastward field Y at the equatorial electrojet station Kodaikanal shows a distinct minimum around noon during any of the years of solar cycle. The sunspot cycle variations of the daily variations of DELTAY are sympathetical with those of DELTAH. Even the day to day fluctuatio ns of the daily range Y are correlated with corresponding changes of H . Abnormal seasonal changes are seen in the daily variations of Y fiel d at Kodaikanal as well as at other observations in India. These signi ficant daily variations of eastward field at Kodaikanal are suggested to be due to a systematic meridional current associated with the elect rojet current.