Modeling and Monitoring South Atlantic Anomaly in Low Earth Orbit Using SSUSI Photometric Data

High energy particles in space are a source of noise for photometric instruments. By careful treatment of this noise, we can extract a great deal of information about in situ particle fluxes (Casadio and Arino, 2011, Schaefer, et al., 2016). Here we consider the analysis of data from the Defense Meteorological Satellite Program's (DMSP) Special Sensor Ultraviolet Spectrographic Imager (SSUSI) instrument to examine particle fluxes (Schaefer, et al., 2016). We demonstrate that the data from the SSUSI 427 nm nadir photometer can be used to effectively monitor particle fluxes from the South Atlantic Anomaly. An accurate extraction of particle information requires an understanding of both the signal (moonglow) and the noise (> 30 MeV protons). We show how this photometer can be used to monitor the shape and flux intensity of the SAA over a solar cycle. These data show the evolution of the SAA in time and space. We also describe how data from the SSUSI scanning imaging spectrograph can be used to isolate and remove particle noise in the images obtained from this spacecraft. Thus, in cases where Spacecraft Size Weight and Power (SWaP) are tightly constrained, photometric instruments can be enlisted for dual use, providing both optical imaging and particle detection. Noise counts in the SSUSI 427 nm nadir photometer binned into 2x2 square degree bins and averaged over the year 2004. Here we see the familiar intensity pattern of the South Atlantic Anomaly.