The Northern and Southern Mid-latitude Ionospheric Trough using Global IGS vTEC map

TL;DR

This study analyzes the mid-latitude ionospheric trough using global ionospheric maps during solar minimum, revealing hemispheric asymmetries, longitudinal development, and correlations with solar wind oscillations.

Contribution

It provides a comprehensive comparison of empirical models with observed MIT positions, highlighting the K"{o}ehnlein & Raitt model's superior accuracy during solar minimum.

Findings

Hemispheric asymmetry in MIT patterns.

Better model agreement in the Northern Hemisphere.

MIT position fluctuations linked to solar wind oscillations.

Abstract

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.