Relationship between substorm onset locations and nightside convection pattern features

This paper presents a study using the Super Dual Auroral Radar Network (SuperDARN) convection database in conjunction with a list of substorm onsets determined from the IMAGE satellite to examine the relationship between substorm onset locations and features of the convection pattern. Particular attention is devoted to the latitude of onset locations compared to the latitude of the near-midnight convection reversal boundary (CRB) and the latitude at which the highest flow velocity (the flow peak) was observed equatorward of the CRB. Because of this focus, the set of observations examined is limited to cases where SuperDARN provided sufficient observations in the midnight sector to determine the latitude of the CRB. Distributions of the latitude difference between the onset location and the CRB and flow peak were examined for different times leading up to substorm onset and for a few different conditions. It was found that the onsets occurred equatorward of the CRB in more than 95% of the cases and that the distribution was approximately centered on the flow velocity peak.