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A model providing long-term datasets of energetic electron precipitation during geomagnetic storms

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posted on 2016-11-11, 16:30 authored by M van de Kamp, A. Seppälä, M. A. Clilverd, C. J. Rodger, P. T. Verronen, I. C. Whittaker
The influence of solar variability on the polar atmosphere and climate due to energetic electron precipitation (EEP) has remained an open question largely due to lack of a long-term EEP forcing dataset that could be used in chemistry-climate models. Motivated by this we have developed a model for 30–1000keV radiation belt driven EEP. The model is based on precipitation data from low-Earth orbiting POES satellites in the period 2002-2012 and empirically described plasmasphere structure, which are both scaled to a geomagnetic index. This geomagnetic index is the only input of the model and can be either Dst or Ap. Because of this, the model can be used to calculate the energy-flux spectrum of precipitating electrons from 1957 (Dst) or 1932 (Ap) onwards, with a time resolution of 1 day. Results from the model compare well with EEP observations over the period of 2002–2012. Using the model avoids the challenges found in measured datasets concerning proton contamination. As demonstrated, the model results can be used to produce the first ever >80 year long atmospheric ionization rate dataset for radiation belt EEP. The impact of precipitation in this energy range is mainly seen at altitudes 70-110km. The ionization rate dataset, which is available for the scientific community, will enable simulations of EEP impacts on the atmosphere and climate with realistic EEP variability. Due to limitations in this first version of the model, the results most likely represent an underestimation of the total EEP effect.

Funding

We thank the Academy of Finland for supporting this research: M. van de Kamp and A. Seppälä were supported by projects 258165, 265005, and 292806 (CLASP: Climate and Solar Particle Forcing), P. T. Verronen was supported by the project 276926 (SECTIC: Sun-Earth Connection Through Ion Chemistry). M. A. Clilverd was supported by the Natural Environmental Research Council grant NE/J008125/1. A. Seppälä, M. A. Clilverd, C. J. Rodger, and P. T. Verronen would like to thank the International Space Science Institute (ISSI), Bern, Switzerland for supporting the “Quantifying Hemispheric Differences in Particle Forcing Effects on Stratospheric Ozone” team (Leader: D. R. Marsh).

History

Citation

Journal of Geophysical Research: Atmospheres, 2016

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

  • VoR (Version of Record)

Published in

Journal of Geophysical Research: Atmospheres

Publisher

American Geophysical Union (AGU), Wiley

issn

2169-897X

eissn

2169-8996

Acceptance date

2016-10-02

Available date

2016-11-11

Publisher version

http://onlinelibrary.wiley.com/doi/10.1002/2015JD024212/abstract

Notes

We would like to thank the geomagnetic data suppliers and the World Data Center for Geomagnetism, Kyoto, for making the Dst index data available via http://wdc.kugi.kyoto-u.ac.jp. The NOAA/POES data used in this study were made available by the National Oceanic and Atmospheric Administration. AARDDVARK data are available from the AARDDVARK Konsortia (see http://www.physics.otago.ac.nz/space/AARDDVARK_homepage.htm). Other data presented in the paper are available from the corresponding author (annika.seppala@fmi.fi).

Language

en

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