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