Transport versus energetic particle precipitation: Northern polar stratospheric NOx and ozone in January–March 2012. Issue 10 (25th May 2016)

• Record Type: Journal Article
• Authors: Päivärinta, S.‐M.; Verronen, P. T.; Funke, B.; Gardini, A.; Seppälä, A.; Andersson, M. E.
• Is Part Of: Journal of geophysical research. Volume 121:Issue 10(2016)
• Page Start: 6085
• Page End: 6100
• Publication Date: 2016-05-25
• Subjects: middle atmosphere dynamics -- energetic particle precipitation -- solar proton event -- sudden stratospheric warming -- odd nitrogen -- ozone; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2015JD024217
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: In early 2012, a strong sudden stratospheric warming (SSW) took place, accompanied by several medium‐scale solar proton events (SPEs). Here we use a chemistry transport model (CTM) in order to assess the relative contributions of (1) intensified downward transport of odd nitrogen (NO x ) and (2) in situ production of NO x by protons, on stratospheric NO x and ozone during January–March 2012. The CTM is constrained by an upper boundary condition for reactive nitrogen (NO y ) species, based on satellite observations from Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board Envisat, and includes a new parameterization of the SPE‐caused effects on NO y and odd hydrogen (HO x ) species. We found that the amount of NO x increases due to both transport and in situ production effects, the intensified descent of NO x dominating the middle and upper stratospheric impact. The model results indicate NO x enhancements of 120–3300% (5–48 ppbv) between 38 and 50 km, caused by the transport of mesosphere/lower thermosphere NO x down to the stratosphere following the SSW. The SPEs increase NO x by up to 820–1200% (14–21 ppbv) at 33 to 50 km. The effect on the stratospheric ozone is larger following the downward transport of NO x than during and after the SPEs. The model predicts ozone losses of up to 17% and 9% at around 40 km due to transport and SPE effects, respectively. Key Points: Effect of NO x descent and SPEs on stratospheric ozone is studied using a chemistry transport model In early 2012, intensified descent after SSW leads to more NH stratospheric ozone loss than SPEs Model includes improved parameterization of NO y upper boundary and SPE‐driven ion chemistry