Observations of Mid-Latitude Ionospheric Density Structures Over North America

Total electron content (TEC) data measured from ground-based GPS receivers is compared to HF backscatter from ionospheric irregularities obtained by SuperDARN radars. A focus is placed on mid-latitudes over North America where recent expansion of the SuperDARN network allows for unprecedented coverage over areas where the density of GPS receivers is greatest. These new mid-latitude SuperDARN radars provide observations of important plasma redistribution processes such as sub-auroral polarization streams (SAPS) and storm enhanced density (SED) which were previously equatorward of the original high latitude radars' field of view. Of interest is the relationship between large-scale plasma structures seen in globally gridded TEC measurements processed at MIT Haystack Observatory and small-scale ionospheric plasma irregularities seen by the SuperDARN radars within these larger density structures.