Solar Cycle Variations in the Polar Ionosphere

The polar ionosphere is a dynamic region that readily responds to changes in solar irradiance, solar wind, the magnetosphere, and the neutral atmosphere. The most recent solar minimum brought to light gaps in the current understanding of the relationship between ionospheric structure and solar irradiance. The Super Dual Auroral Radar Network (SuperDARN) offers an invaluable dataset for studying long-term ionospheric variability, as it has been continuously providing extensive coverage of the northern and southern polar ionosphere since 1995 (the solar minimum preceding the 23rd solar cycle). An under-utilized portion of the SuperDARN dataset is the ground-backscatter: the backscatter that returns from a reflection point on the ground along an open (or irregularity-free) propagation path. The ground-backscatter provides a measure the ionospheric density at the peak of the radar signal's path. These measurements are used to the examine the changes in the bottomside, polar ionosphere over the 23rd and 24th solar cycles.