A study has been performed on the effect of the By and Bz components of the Interplanetary Magnetic Field (IMF), as measured by the WIND satellite, on the occurrence of pulsed ionospheric flows as observed by the CUTLASS Finland radar. These flows have been suggested as being created at the ionospheric footprint of newly reconnected field lines. The statistical location of the pulsed flows is strongly dependent on the IMF By component, moving to the pre-noon sector during intervals of positive By and into the post-noon sector for intervals of negative By. These results directly confirm previous predictions, demonstrating that during intervals of flux transfer at the magnetopause, pulsed ionospheric convective flows are initiated. In the northern hemisphere these flows are shifted about noon in the opposite sense to the IMF By component, consistent with the average ionospheric convection pattern. ¿ 1999 American Geophysical Union