Open AccessA superposed epoch study of SuperDARN convection observations during substorms
Author(s) -
Bristow W. A.,
Jensen Poul
Publication year - 2007
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006ja012049
Subject(s) - substorm , geophysics , convection , geology , polar cap , midnight , flow (mathematics) , epoch (astronomy) , meridional flow , zonal and meridional , geodesy , physics , atmospheric sciences , ionosphere , mechanics , astrophysics , magnetosphere , plasma , astronomy , stars , quantum mechanics
Case studies of flow patterns during substorms have revealed characteristic patterns in the period leading to expansion onset. Velocities in the premidnight region have been observed to become strongly sheared, and the premidnight convection reversal has been observed to extend across the midnight meridian. At expansion onset, the shear decreases and flow at midnight becomes meridional, out of the polar cap. The study presented here superposes flow patterns from 10 substorm intervals to determine the average flow patterns. The study confirms the findings of the case studies and extends them to additional local time sectors. In addition, changes to the flow pattern after expansion onset are examined.