Observations of TEC depletions over Indian low latitudes

Results pertaining to the latitudinal extent of the ionospheric irregularities in terms of TEC depletions have been presented for the two nights namely; 28 October 2004 and 7 February 2005. This study has been carried out using the GPS–TEC over the Indian low latitude stations, at Udaipur, Hyderabad and Bengaluru. This is probably the first report of simultaneous GPS observation of TEC depletions over different latitudes from the Indian sector. The results show that the amplitude of TEC depletions due to the equatorial spread F may vary with time and the location of the observation. The maximum amplitude of the TEC depletion has been found to be about 30 TECU over Hyderabad. The depletions in TEC are found to be field aligned.