Geomagnetic Sq & SD at Sabhawala (Dehra Dun) & Alibag during 1964-65

Abstract

A comparative study of the solar quiet dally magnetic variation Sq and the disturbance daily variation S_D, recorded at Sabhawala (Dehra Dun) and Alibag during the quiet-sun years 1964 and 1965, is presented and the seasonal characteristics discussed. The mean Sq (<i>H</i>)<i>, </i>Sq (<i>Z</i>)<i>, </i>Sq (<i>D</i>) ranges at Sabhawala are found to be 18γ, 17γ , 3.5 as against 35γ 21γ 2.7 at Alibag. The mean S_D (<i>H</i>)<i>, </i>S_D (<i>Z</i>)<i>, </i> S_D (<i>D</i>) ranges at Sabhawala work out as 24γ, 6γ, 0.9 as against 21γ, 8γ, 0.8 at Alibag. While at Alibag, the peak in Sq (<i>H</i>) variation is observed around 1130 LT in all the three seasons, at Sabhawala, it occurs around 1030 LT in winter, 1300 LT in equinoxes and 1400 LT in summer months. These values are also compared with the already published results of Hyderabad for 1965. The differences in Sq arise from the latitudinal separation between Alibag-Hyderabad and Sabhawala; the proximity of Sabhawala to the northern hemispheric Sq current system focus, and the coastal character of Alibag. The SD variations at the three stations show similar seasonal characteristics.