SuperDARN convection and Sondrestrom plasma drift

Plasma convection measurements by the Goose Bay and Stokkseyri SuperDARN ra dar pair and the Sondrestrom incoherent scatter radar are compared in three different ways, by looking at the line-of-sight (1-o-s) velocities, by com paring the SuperDARN vectors and corresponding Sondrestrom 1-o-s velocities and by comparing the end products of the instruments, the convection maps. All three comparisons show overall reasonable agreement of the convection measurements though the data spread is significant and for some points a st rong disagreement is obvious. The convection map comparison shows a tendenc y for the SuperDARN velocities to be often less than the Sondrestrom drifts for strong flows (velocities > 1000 m/s) and larger for weak flows (veloci ties < 500 m/s). On average, both effects do not exceed 35%. Data indicate that inconsistencies between the two data sets occur largely at times of fa st temporal variations of the plasma drift and for strongly irregular flow according to the SuperDARN convection maps. These facts indicate that the o bserved discrepancies are in many cases a result of the different spatial a nd temporal resolutions of the instruments.