Travelling ionospheric disturbances are plasma density fluctuations usually driven by atmospheric gravity waves in the neutral atmosphere. The aim of this study is to attribute multi-instrument observations of travelling ionospheric disturbances to gravity waves generated in the upper atmosphere at high latitudes or gravity waves generated by tropospheric weather systems at mid latitudes.

We present a second-level calibration method for electron density measurements from multi-beam incoherent scatter radars. It is based on the well-known Flat field correction method used in imaging and photography. The methods improve data quality and useability as they account for unaccounted, and unpredictable variations in the radar system. This is valuable for studies where inter-beam calibration is important such as studies of polar cap patches, plasma irregularities and turbulence.

The solar wind interaction with Earth’s magnetic field deposits energy into the upper portion of the atmosphere at high latitudes. The coupling process that modulates the ionospheric convection and intensity of ionospheric currents leads to formation of densely ionized patches convecting across the polar cap. The ionospheric currents launch traveling ionospheric disturbances (TIDs) propagating equatorward. The polar cap patches and TIDs are then observed by networks of radars and GPS receivers.

Convection reversal boundary (CRB) is a special characteristic of plasma flow patterns in the high-latitude ionosphere. It is typically a border line between regions with closed and open Earth’s magnetic field lines. This paper investigates seasonal and solar cycle trends in the CRB location. We use an extensive Super Dual Auroral Radar Network data base for 19 years of operation and apply a non-standard approach of making monthly averaged convection maps.