Observations of Ionospheric Scintillations over Koudougou and Bac Lieu
Tinlé Pahima *
Analytical Chemistry, Space and Energy Physics Laboratory (Laboratoire de Chimie Analytique, de Physique Spatiale et Energétique : L@CAPSE), Burkina Faso.
Sibri Alphonse Sandwidi
Analytical Chemistry, Space and Energy Physics Laboratory (Laboratoire de Chimie Analytique, de Physique Spatiale et Energétique : L@CAPSE), Burkina Faso.
Christian Zoundi
Analytical Chemistry, Space and Energy Physics Laboratory (Laboratoire de Chimie Analytique, de Physique Spatiale et Energétique : L@CAPSE), Burkina Faso.
Doua Allain Gnabahou
Analytical Chemistry, Space and Energy Physics Laboratory (Laboratoire de Chimie Analytique, de Physique Spatiale et Energétique : L@CAPSE), Burkina Faso.
Frédéric Ouattara
Analytical Chemistry, Space and Energy Physics Laboratory (Laboratoire de Chimie Analytique, de Physique Spatiale et Energétique : L@CAPSE), Burkina Faso.
Le Huy Minh
Institute of Earth Sciences, Vietnam Academy of Science and Technology, Vietnam.
*Author to whom correspondence should be addressed.
Abstract
This paper aims to study the scintillations observed in ionospheric variations at Koudougou (Burkina Faso) and Bac Lieu (Vietnam) GPS stations. Ground receivers at the Koudougou and Bac Lieu stations record GNSS signals that are useful for studying ionospheric variations and the coupling effects between the magnetosphere and ionosphere. Total Electron Content (TEC) of both stations have been estimated by using the carrier phase method, a combination of code and phase measurements. The rate of change of the TEC index (ROTI) have been calculated as a function of time and its daily variations have been studied. The results show typical characteristics of diurnal and seasonal variations in ionospheric scintillation through the years 2012 to 2016 over Koudougou and from 2015 to 2019 over Bac Lieu. The strongest ionospheric scintillations are observed during equinoxes (spring and autumn) and the most intense are observed during spring equinoxes over the two stations. Strong phase scintillations are observed during night with high ROTI index (ROTI \(\ge\) 0,5 TECU/mn) recorded before sunrise (0000 UT to 0200 UT) and after sunset (1930 UT to 2300 UT). The higher ROTI values at Koudougou (~2.5 TECU/mn) could be explained by the fact that, compared with Bac Lieu (~1.8 TECU/mn) Koudougou is closer to the magnetic equator.
Keywords: Ionosphere, scintillations, GNSS, GPS station, seasons, TEC