The PIs will combine ground-based radar data with DMSP satellite data collected during a four-month period to study global response times. The four operational DMSP satellites in orbit allow resolution of the response time measured by the satellite data to be as good as a few minutes. This proposal will analyze the ionospheric response seen in the radar and satellite data to determine the response time as a function of MLT and location. Results should give a better understanding of the evolution of the convection pattern in the polar ionosphere after a sign reversal in the IMF.***
