Interplanetary magnetic field directions inferred from Digisonde measurements of the convection flow direction over the polar cap

The interplanetary magnetic field (IMF) exerts a strong influence on high latitude F-region convection and, therefore, the IMF is an important input parameter in models of the high latitude ionosphere. The IMF z component controls the energy input and the radius of the convection reversal [e.g. Zi et al., 1987] whereas the IMF y component controls the geometry of convection pattern [e.g, Heppner and Maynard, 1987]. The present paper examines the possibility of using a Digisonde located at Qaanaaq, near the geomagnetic pole, to infer the direction of the y component of the IMF. The authors have used 16 days of Digisonde data to derive regression lines relating the IMF y component (measured by the IMP8 satellite) to the convection flow direction measured by the Digisonde at Qaanaaq. They then utilised the derived relationship and reversed the procedure to infer the direction of the IMF y component (positive or negative) from an independent further 16 days of data