Geomagnetic Sq Variations and Parameters of the Indian Electrojet for 1958, 1959

Abstract

Geomagnetic Sq variations at Trivandrum, Annamalainagar (both close to the magnetic equator) and Alibag are examined for the different seasons for the year 1958 and 1959.  The ranges in H for the observatories close to the magnetic equator are as usual very large.  Maximum ranges in H and Z occur in the equinoctial months while maximum range in D occurs during the summer.  Other characteristics of the variations are pointed out, especially the anomalous nature of Sq (Z) at Trivandrum and Annamalainagar.

Using the magnitudes of Sq (H) at the three observatories for the periods April to August (a period during which the solar noon-znith angle varies through about 20 for all the three observatories), estimates of the parameters of the Indian electrojet are made.  The half-width of the electrojet is found to be nearly 300 km.  The total current strength in the electrojet is about 148 A/km or 60,000 A/degree latitude.  The factor by which the normal Sq current strength is intensified at the magnetic equator is found to be 2.4.