SMuK 2021 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 3: Near Earth Space I
EP 3.3: Talk
Tuesday, August 31, 2021, 11:45–12:00, H8
Validation of SSUSI derived auroral ionization rates and electron densities — •Stefan Bender1,2, Patrick Espy1,2, and Larry Paxton3 — 1Norwegian University of Science and Technology, Trondheim, Norway — 2Birkeland Centre for Space Science, Bergen, Norway — 3APL, Johns Hopkins University, Laurel, Maryland, USA
Solar, auroral, and radiation belt electrons enter the atmosphere at polar regions leading to ionization and affecting its chemistry. Climate models usually parametrize this ionization and the related changes in chemistry based on satellite particle measurements. Precise measurements of the particle and energy influx into the upper atmosphere are difficult because they vary substantially in location and time. Widely used particle data are derived from the POES and GOES satellite measurements which provide in-situ electron and proton spectra.
Here we use the electron energy and flux data products from the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) instruments on board the Defense Meteorological Satellite Program (DMSP) satellites. This formation of currently three operating satellites observes the auroral zone in the UV from which electron energies and fluxes are inferred in the range from 2 keV to 20 keV. We use these electron energies and fluxes to calculate ionization rates and electron densities in the lower thermosphere (≈90–150 km), and validate them against EISCAT ground-based measurements. We find that with the current standard parametrizations, the SSUSI-derived auroral electron densities (90–150 km) agree well with the ground-based measured ones.