K M Kotadia
Articles written in Proceedings – Section A
Volume 43 Issue 5 May 1956 pp 306-308
Volume 43 Issue 6 June 1956 pp 394-399
The paper contains an analysis of the variation of the midday values of foF2, h′F2 and hpF2 with lunar phase at Ahmedabad during the years 1954 and 1955 and of foF2 alone at Bombay, Madras and Tiruchirapalli during 1954. It is found that while the semidiurnal lunar tidal variations at Ahmedabad and Bombay agree in phase with those observed at middle latitudes, the phase reverses in direction between Bombay and Madras. The results are compared with those relating to Huancayo and Singapore.
Volume 43 Issue 6 June 1956 pp 400-400 Erratum
Volume 46 Issue 5 November 1957 pp 349-353
Volume 50 Issue 4 October 1959 pp 259-271
From a study of spread-F or F-scatter at Ahmedabad during the four years 1954–57 of increasing sunspot activity, it was found that the time of its maximum occurrence receded from 03 hr. in low sunspot years to an hour or two before midnight in high sunspot years. This was particularly well seen in the winter and equinoctial months. Also, maximum spread-F activity which was found in summer in sunspot minimum mum years, occurred in equinoxes in maximum sunspot years. The frequency of occurrence of spread-F was found to be a maximum when
It is concluded that (1) spread-F at Ahmedabad geomagnetic latitude (
Volume 60 Issue 5 November 1964 pp 352-367
In this paper, the ionospheric data of Kodaikanal (magnetic dip 3·5° N) have been examined to study the relation between the critical frequency of the equatorial sporadic E layer and the horizontal component of the earth’s magnotic field, with special reference to the behaviour of the electrojet both under normal and under disturbed conditions. Some specific SC type magnetic storms have been analysed to study the effect of the storms on the electrojet.
It is shown that the blanketing frequency of Es can be taken to be equal to the critical frequency of the normal E-layer and it is suggested that the high value of foEs might be due to the subsidence and conversion of E layer ionization into eddy-clouds forming as a result of strong wind shear in the electrojet. It is also shown that foEs and H are fairly well connected under