University of Oulu

Nesse Tyssøy, H., Sinnhuber, M., Asikainen, T., Bender, S., Clilverd, M. A., Funke, B., et al. (2022). HEPPA III intercomparison experiment on electron precipitation impacts: 1. Estimated ionization rates during a geomagnetic active period in April 2010. Journal of Geophysical Research: Space Physics, 127, e2021JA029128.

HEPPA III intercomparison experiment on electron precipitation impacts : 1. estimated ionization rates during a geomagnetic active period in April 2010

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Author: Nesse Tyssøy, H.1; Sinnhuber, M.2; Asikainen, T.3;
Organizations: 1Department of Physics and Technology, Birkeland Centre for Space Science, University of Bergen, Bergen, Norway
2Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
3University of Oulu, Oulu, Finland
4Birkeland Centre for Space Science, Norwegian University of Science and Technology, Trondheim, Norway
5British Antarctic Survey (UKRI-NERC), Cambridge, England
6Instituto de Astrofísica de Andalucía, CSIC, Granada, Spain
7Space and Earth Observation Centre, Finnish Meteorological Institute, Helsinki, Finland
8LASP, University of Colorado, Boulder, CO, USA
9University of Otago, Dunedin, New Zealand
10PMOD/WRC, Davos, Switzerland
11St. Petersburg State University, St. Petersburg, Russia
12University of Rostock, Rostock, Germany
13Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.2 MB)
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Language: English
Published: American Geophysical Union, 2021
Publish Date: 2022-01-03


Precipitating auroral and radiation belt electrons are considered an important part of the natural forcing of the climate system. Recent studies suggest that this forcing is underestimated in current chemistry-climate models. The High Energy Particle Precipitation in the Atmosphere III intercomparison experiment is a collective effort to address this point. Here, eight different estimates of medium energy electron (MEE) (gt; 30 kev) ionization rates are assessed during a geomagnetic active period in April 2010. The objective is to understand the potential uncertainty related to the MEE energy input. The ionization rates are all based on the Medium Energy Proton and Electron Detector (MEPED) on board the NOAA/POES and EUMETSAT/MetOp spacecraft series. However, different data handling, ionization rate calculations, and background atmospheres result in a wide range of mesospheric electron ionization rates. Although the eight data sets agree well in terms of the temporal variability, they differ by about an order of magnitude in ionization rate strength both during geomagnetic quiet and disturbed periods. The largest spread is found in the aftermath of enhanced geomagnetic activity. Furthermore, governed by different energy limits, the atmospheric penetration depth varies, and some differences related to latitudinal coverage are also evident. The mesospheric NO densities simulated with the Whole Atmospheric Community Climate Model driven by highest and lowest ionization rates differ by more than a factor of eight. In a follow-up study, the atmospheric responses are simulated in four chemistry-climate models (CCM) and compared to satellite observations, considering both the CCM structure and the ionization forcing.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Issue: Accepted articles
DOI: 10.1029/2021JA029128
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
1171 Geosciences
Funding: This study as well as the companion paper are a collaborative effort of the working group five: Medium Energy Electrons (MEE) Model-Measurement intercomparison of the SPARC Solaris-Heppa initiative, see The authors thank the SPARC/WCRP for supporting the initial working group meetings. H. Nesse Tyssøy is supported by the Norwegian Research Council (NRC) under contract 223252 and 302040. S. Bender and C. Smith-Johnsen are also supported by the NRC under contract 223252. T. Asikainen is supported by the Academy of Finland (PROSPECT project no: 321440). B. Funke acknowledges financial support from the Agencia Estatal de Investigación of the Ministerio de Ciencia, Innovación y Universidades through projects ESP2017-87 143-R and PID2019-110689RB-I00, as well as the Centre of Excellence “Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). J. Pettit's work is funded by NSF CEDAR grant AGS 1651 428. E.Rozanov's and T. Sukhodolov's work on the manuscript is done in the SPbSU “Ozone Layer and Upper Atmosphere Research Laboratory” supported by the Ministry of Science and Higher Education of the Russian Federation under agreement 075-15-2021-583 and was partly supported by German Russian cooperation project ”H-EPIC” funded by the Russian Foundation for Basic Research (RFBR project No 20-55-12 020). M. Sinnhuber work was partly supported by the German Research Foundation DFG (grant SI 1088/7-1). The work of P. T. Verronen is supported by the Academy of Finland (project No. 335 555 ICT-SUNVAC). The development of AISstom has been supported by the German Science Foundation (DFG; grant no. WI4417/2-1). J.M. Wissing is supported by the German Aerospace Center (DLR; grant no. D/921/67 284 894). M. Sinnhuber, M. A. Clilverd, B. Funke, C. E. Randall, C. J. Rodger, J. M. Wissing, and P. T. Verronen would like to thank the International Space Science Institute, Bern, Switzerland for supporting the project ”Quantifying Hemispheric Differences in Particle Forcing Effects on Stratospheric Ozone” (Leader: D. R. Marsh).
Copyright information: © 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.