Occurrence characteristics and causative mechanisms of daytime L-band scintillations over Dibrugarh, a station at the northern edge of EIA during 2010 – 2014

Abstract

Dibrugarh $( 27.5 ^{\circ}\mathrm {N} , 95 ^{\circ}\mathrm {E} , 43 ^{\circ}$ dip), a location at the northern edge of EIA behaves as low as well as mid latitude location during nighttime. The nighttime L-band scintillations during ascending half of the solar cycle 24 (from January, 2010 to December, 2014) over Dibrugarh are found to be attributed to both equatorial irregularities and sporadic-E (Dutta et al., 2018a). The occurrence characteristics and possible mechanisms of daytime scintillations are investigated and presented in this paper at the same frequency for the same phase of solar cycle. The daytime amplitude scintillations are found to be associated with insignificant phase scintillations, TEC depletions, ROT and ROTI (Figure 1). This implies that no plasma bubbles are formed during daytime scintillations over the location. The association of insignificant TEC depletions/ ROT fluctuations during daytime scintillations were observed earlier at Guilin $( 25.3 ^{\circ}\mathrm {N} , 110.3 ^{\circ}\mathrm {E})\mathrm {a}$ station near the northern crest of EIA (Zou and Wang, 2009; Zou, 2011) and at equatorial station University Kebangsaan Malaysia (UKM), Malaysiya $( 2.6 ^{\circ}\mathrm {N} , 101.5 ^{\circ}\mathrm {E})($ Seif et al., 2012). They reported that daytime scintillations were caused by small scale irregularities in E-region.