SMuK 2023 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 9: Poster
EP 9.19: Poster
Wednesday, March 22, 2023, 17:30–19:00, HSZ OG1
Empirical modelling of SSUSI-derived auroral ionization rates — •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. 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. The currently three operating satellites directly observe the auroral emissions in the UV on a ≈3000 km wide swath with a ≈10×10 km2 pixel resolution. From the UV emissions electron energies and fluxes are inferred in the range from 2 keV to 20 keV. We use these observed electron energies and fluxes to calculate auroral ionization rates in the lower thermosphere (90–150 km). We present an empirical model of these ionization rates according to magnetic local time and geomagnetic latitude. The model is particularly targeted for use in climate models that include the upper atmosphere, such as WACCM-X or EDITh. We also present a comparison to current implementations for ionization rates used in these two models.