Northern Hemisphere atmospheric influence of the solar proton events and ground level enhancement in January 2005

C.H. Jackman, E.L. Fleming, D.R. Marsh, F.M. Vitt, R.G. Roble, C.E. Randall, P.F. Bernath, B. Funke, M. López-Puertas, S. Versick, G.P. Stiller, A.J. Tylka

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Solar eruptions in early 2005 led to a substantial barrage of charged particles on the Earth's atmosphere during the 16g-21 January period. Proton fluxes were greatly increased during these several days and led to the production of HO (H, OH, HO2) and NO (N, NO, NO ), which then caused the destruction of ozone. We focus on the Northern polar region, where satellite measurements and simulations with the Whole Atmosphere Community Climate Model (WACCM3) showed large enhancements in mesospheric HOx and NOx constituents, and associated ozone reductions, due to these solar proton events (SPEs). The WACCM3 simulations show enhanced short-lived OH and HO concentrations throughout the mesosphere in the 60-82.5° N latitude band due to the SPEs for most days in the 16-21 January 2005 period, somewhat higher in abundance than those observed by the Aura Microwave Limb Sounder (MLS). These HOx enhancements led to huge predicted and MLS-measured ozone decreases of greater than 40 % throughout most of the northern polar mesosphere during the SPE period. Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measurements of hydrogen peroxide (H2O2) show increases throughout the stratosphere with highest enhancements of about 60 pptv in the lowermost mesosphere over the 16-18 January 2005 period due to the solar protons. WACCM3 predictions indicate H2O enhancements over the same time period of about three times that amount. Measurements of nitric acid (HNO ) by both MLS and MIPAS show an increase of about 1 ppbv above background levels in the upper stratosphere during 16-29 January 2005. WACCM3 simulations show only minuscule HNO3 increases (
Original languageEnglish
Pages (from-to)6153-6166
Number of pages14
JournalAtmospheric Chemistry and Physics
Issue number13
Publication statusPublished - 1 Jan 2011

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