Articles | Volume 34, issue 2
Regular paper
15 Feb 2016
Regular paper |  | 15 Feb 2016

Seasonal and solar cycle variations in the ionospheric convection reversal boundary location inferred from monthly SuperDARN data sets

Alexander V. Koustov and Robyn A. D. Fiori

Abstract. Multi-year (1995–2013) velocity data collected by the Super Dual Auroral Network (SuperDARN) HF radars are considered to investigate seasonal and solar cycle variations of the convection reversal boundary (CRB) location for interplanetary magnetic field (IMF) Bz < 0. By considering monthly data sets we show that the CRB is at higher latitudes in summer between 1995 and 2007. The poleward shifts are on the order of 2–5°. After 2007, the seasonal effect weakens, and the highest latitudes for the CRB start to occur during the winter time. We show that the CRB latitudes decrease with an increase of the IMF transverse component at a rate of (1–2°)/2 nT. Because of this effect, on average, the CRB latitudes are lower during high solar activity periods with stronger IMFs. We also confirm the effect of the CRB dawn-dusk shifts related to the IMF changes in the IMF By sign.

Short summary
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.