Irregular Fluctuations in H Field at Kodaikanal

Abstract

Considering the hourly values of (^rH—^rHq), where ^rH is the range in H for a particular hour and ^rHq, IS the mean of ranges for the same hour on five international quiet days of the month, as measures of the hourly intensity of irregular fluctuations in the horizontal field, a study of the variations in their incidence at Kodaikanal is made for the period 1952-53. It is found that the fluctuations are the least in the early morning hours and the largest around local noon. The seasonal changes in the form of diurnal variation of the incidence of the fluctuations become prominent only for dayswith international character figure C>1. The effect of increased magnetic activity in all the seasons is a general increase in the intensity of fluctuations, which however, is not uniform for all hours. The increase is large around noon and the least, early in the morning; the increase during night, which is generally considerable, becomes particularly marked during equinoctial months.