The northern and southern mid-latitude ionospheric trough using global IGS vTEC maps

摘要: Abstract The aim of this work is the analysis mid-latitude ionospheric trough (MIT) using Global Ionospheric Maps from IGS (GIMs) during solar minimum, year 2008. This study was performed for different local times, 22, 00, 02 and 04 LT on Northern Southern hemisphere simultaneously. In two hemispheres MIT show asymmetric pattern. high-latitude troughs are clearly distinguished in autumn winter. Another feature longitudinal development towards west geomagnetic pole covering a wider area Hemisphere. Five empirical reference models were tested compared with minimum position obtained GIMs at times both hemisphere. results better agreement observations Hemisphere specially Koehnlein & Raitt model. Fluctuations 9 days 27 days found, which could be related wind oscillations, especially 00 02 LT hemisphere, suggesting link between them.