[1] Indian Inst Trop Meteorol, Pune 411008, Maharashtra, India
[2] Banaras Hindu Univ, Dept Geophys, Varanasi 221005, Uttar Pradesh, India
[3] Indian Inst Geomagnetism, KSK Geomagnet Res Lab, Allahabad 221505, Uttar Pradesh, India
[4] Univ Petr & Energy Studies, Dept Phys, Dehra Dun 248007, Uttar Pradesh, India
[5] Banaras Hindu Univ, Dept Phys, Varanasi 221005, Uttar Pradesh, India