Pettit, J, Randall, CE, Marsh, DR orcid.org/0000-0001-6699-494X et al. (6 more authors) (2018) Effects of the September 2005 Solar Flares and Solar Proton Events on the Middle Atmosphere in WACCM. Journal of Geophysical Research: Space Physics, 123 (7). pp. 5747-5763. ISSN 2169-9402
Abstract
This work investigates middle atmosphere effects of the September 2005 solar flares and solar proton events (SPEs). X‐17 and X‐6.2 flares occurred on 7 and 9 September, respectively, while two moderate SPEs occurred on 10 and 15 September. Flare ionization and dissociation were calculated in the Whole Atmosphere Community Climate Model (WACCM) using the Flare Irradiance Spectral Model. Proton measurements from the Geostationary Operational Environmental Satellite system were used to compute solar proton ionization. SPEs are shown to have a larger impact than solar flares on the polar stratosphere and mesosphere; however, flares have a larger influence on the sunlit and equatorial lower thermosphere. The two flares differed significantly with respect to photon spectrum. The larger, X‐17 flare was stronger during the impulsive phase, while the X‐6.2 flare was stronger during the gradual phase. This resulted in the X‐17 flare causing more initial ionization but for a shorter duration. The simulated flare impacts also differed because specific wavelengths of the flares influenced the atmosphere above the model top. Model‐measurement comparisons show that WACCM captures the overall timing and spatial distribution of the observed electron enhancements, indicating a reasonable simulation of flare and SPE‐induced ionization. Both the SPEs and flares caused odd nitrogen increases in the mesosphere. Odd hydrogen produced in the lower mesosphere by the SPEs led to short‐lived ozone decreases of nearly 100%. The flares caused small temperature increases in the lower thermosphere but had no effect on the stratosphere.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | ©2018. American Geophysical Union. All Rights Reserved. This is the published version of the following article: Pettit, J, Randall, CE, Marsh, DR et al. (2018) Effects of the September 2005 Solar Flares and Solar Proton Events on the Middle Atmosphere in WACCM. Journal of Geophysical Research: Space Physics, 123 (7). pp. 5747-5763. ISSN 2169-9402, which has been published in final form at https://doi.org/10.1029/2018JA025294. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. |
Keywords: | solar flares; thermosphere; solar proton events; mesosphere; energetic particle precipitation; modeling |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Astrophysics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 22 Nov 2018 11:26 |
Last Modified: | 15 Dec 2018 01:39 |
Status: | Published |
Publisher: | AGU |
Identification Number: | 10.1029/2018JA025294 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:138967 |