Response of Scintillation and Total Electron Content (TEC) over Indian regions during the Quiet Days

Abstract

GPS derived scintillation (S₄-Index) and TEC data recorded at different location in India (Delhi, Bhopal, Bangalore & Trivandrum). For the first time we are reporting scintillation and TEC activities during quiet days. Quiet days are define as a very low or negligible solar activity that is opposite of disturbed day. For the study of quiet days variations we analyses some space weather indices like Dst index , AE index, Kp Index and interplanetary magnetic field Bz. During the study on 6-7 august 2016 we noticed on 6 October Bz fluctuated between -1 to +2nT that means little bit disturbance occurred and next day on 7 October it was +3 to -2 nT. AE index was 500 on 6 October and it was decrease 290 on 7 October .Dst Value observed -16.5nT on 6 October in the mid night on 6 October it was -22nT. All this space weather parameter shows small scale space weather activities. For this study we are choosing two quiet days, 6-7 October 2016 and 25-26 august 2017. Both This quiet days are observed during the down phase of solar cycle 24^th, during this study we noticed that maximum scintillation activities (< 1.5 and < 1) recorded at Bhopal and Bangalore station as compare to Delhi and Trivandrum stations and maximum TEC activities observed at Bhopal and Delhi during minor geomagnetic activity on 6-7 October 2016. The study of another quiet day 25-26 August 2017, we observed maximum scintillation activities ( 1.6 and 1) over Bhopal and Bangalore stations, at Delhi and Trivandrum stations we noticed minor scintillation activities (<0.5 and  <0.3) and maximum TEC fluctuations recorded at Bhopal and Delhi stations as compare to Bangalore and Trivandrum stations. Quiet days are not fully quiet days we can get some response in ionosphere at low mid-latitudes and EIA regions. This paper, for the first time, reports on scintillation and TEC characteristics observed at the L-band frequency of 1.575 GHz over the Indian region During 2 quiet days in 2016-2017.  We present here the results for four stations on the scintillation and TEC characteristics of the L-band scintillations (S4 index), simultaneously measured by these receivers in the Indian region and the possible effects on GPS navigation.