TEC fluctuation during magnetically disturbed events of April 2010 on high latitude station.

The ionospheric parameters, strongly dependent on the solar conditions and on the complex behavior of the magnetosphere, are very interesting for studying the complex phenomena and high degree of space time variability of the ionosphere occurring at the high latitude regions. In order to see the behavior of the high latitude ionosphere during the geomagnetically active events of extreme minimum phase of solar cycle 23 and starting phase of 24 solar cycle, in April 2010 moderate geomagnetic storms have been identified and represented in fairly well detail in the present investigation. The ionospheric observations have been obtained from dual frequency GPS, installed and operated at Indian scientific base station Maitri (71.45S and 11.45E) Antarctica, during December. 2009 to December 2010. Situated on auroral region mainly two parameters from the GPS observations, (I) Total Electron Content (TEC), (II) Total Electron Content Rate (TECR) have been considered for the present study. On storm days, the percentage deviations of TEC from geomagnetically quiet days at high latitudes shows the variations of ionosphere in terms of positive and negative ionospheric storms. The results therefore showed the dependence of occurrence characteristics of TEC on the solar activity.