Determining Latitudinal Extent of Energetic Electron Precipitation Using MEPED On‐Board NOAA/POES. Issue 9 (25th September 2022)

• Record Type: Journal Article
• Authors: Babu, E. M.; Tyssøy, H. Nesse; Smith‐Johnsen, C.; Maliniemi, V.; Salice, J. A.; Millan, R. M.; Richardson, I. G.
• Is Part Of: Journal of geophysical research. Volume 127:Issue 9(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-25
• Subjects: particle precipitation model -- medium energy electrons -- geomagnetic indices -- solar wind structures -- magnetospheric dynamics; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2022JA030489
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Energetic Electron Precipitation (EEP) from the plasma sheet and the radiation belts ionizes the polar lower thermosphere and mesosphere. EEP increases the production of NO x and HO x, which will catalytically destroy ozone, an important element of atmospheric dynamics. Therefore, measurement of the latitudinal extent of the precipitation boundaries is important in quantifying the atmospheric effects of the Sun‐Earth interaction. This study uses measurements by the Medium Energy Proton Electron Detector (MEPED) of six NOAA/POES and EUMETSAT/METOP satellites from 2004 to 2014 to determine the latitudinal boundaries of EEP and their variability with geomagnetic activity and solar wind drivers. Variation of the boundaries for different electron energies and Magnetic Local Time (MLT) is studied. Regression analyses are applied to determine the best predictor variable based on solar wind parameters and geomagnetic indices. The highest correlation was found for the pressure‐corrected Dst index when applying a linear regression model. A model of the equatorward EEP boundary is developed separately for three different energy channels, >43, >114, and >292 keV, and for 3 hour MLT sectors. For >43 keV EEP, 80% of the equatorward boundaries predicted by the model are within ±2.2° cgmlat. The model exhibits a solar cycle bias where it systematically exaggerates the equatorward movement of the EEP region during solar minimum. The highest accuracy of the model is found in periods dominated by corotating interaction regions/high speed solar wind streams. The result will be a key element for constructing a model of EEP variability to be applied in atmosphere climate models. Plain Language Summary: Charged particles trapped in the Earth's magnetic field get accelerated to high energies through various magnetospheric processes. They can eventually precipitate into the Earth's atmosphere in a process known as Energetic Electron Precipitation or EEP. EEP deposits energy in the mesosphere and lower thermosphere which increase the production of ozone‐depleting substances. Vertical transport of these, in particular during winter, can lead to indirect destruction of stratospheric ozone, a crucial element of atmospheric dynamics. Therefore, measurement of the latitudinal extent of EEP is important in quantifying the atmospheric effects of the Sun‐Earth interaction. We use measurements from six NOAA/POES and EUMETSAT/METOP satellites from 2004 to 2014 to determine the equatorward latitudinal boundaries of EEP. We investigate how they correlate with solar wind parameters and geomagnetic indices to identify the best predictor for EEP boundaries. The result will be a key element for constructing a model of EEP variability to be applied in atmosphere climate models. Key Points: A model predicting equatorward extent of >43 keV electron precipitation is developed based on pressure‐corrected Dst The model has an error estimate of ±2.2° cgmlat over a full solar cycle (2004–2014) The model has the highest accuracy during periods dominated by high‐speed solar wind streams