WHAM Geocororal Hydrogen Emission Observations Over Changing Solar Geophysical Conditions

We will present geocoronal Hα intensity data taken over a four year time span during near solar minimum through near solar maximum solar geophysical conditions. These data were taken with the Wisconsin H-alpha Mapper (WHAM) Fabry-Perot which has been acquiring an extensive body of upper thermospheric/exospheric hydrogen Balmer-α (6563 Å) fluorescence emission data since 1997. The bulk of this data set consists of the terrestrial spectra present in astronomical observations made at the Kitt Peak Observatory near Tucson, Arizona. WHAM operates at a resolving power of about 25,000, with a resulting resolution of 12 km/sec (0.26 Å at Hα ) which is too low for line profile studies but sufficient for separation of the doppler shifted galactic and geocoronal line components and retrieval of the airglow intensities.