Open AccessObservation of NO x enhancement and ozone depletion in the Northern and Southern Hemispheres after the October–November 2003 solar proton events
Author(s) -
LópezPuertas M.,
Funke B.,
GilLópez S.,
von Clarmann T.,
Stiller G. P.,
Höpfner M.,
Kellmann S.,
Fischer H.,
Jackman C. H.
Publication year - 2005
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005ja011050
Subject(s) - stratosphere , atmospheric sciences , atmosphere (unit) , polar night , ozone , polar , ozone depletion , environmental science , arctic , atmospheric sounding , ozone layer , atmosphere of earth , climatology , physics , geology , meteorology , astronomy , oceanography
The large solar storms in October–November 2003 produced enormous solar proton events (SPEs) where high energetic particles reached the Earth and penetrated into the middle atmosphere in the polar regions. At this time, the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) was observing the atmosphere in the 6–68 km altitude range. MIPAS observations of NO x (NO + NO 2 ) and O 3 of the period from 25 October to 14 November 2003 are the first global measurements of NO x species, covering both the summer (daylight) and winter (dark) polar regions during an SPE. Very large values of NO x in the upper stratosphere of 180 ppbv (parts per billion by volume) have been measured, and a large asymmetry in northern and southern polar cap NO x enhancements was found. Arctic mean polar cap (>60°) NO x enhancements of 20 to 70 ppbv between 40 to 60 km lasted for at least 2 weeks, while the Antarctic mean NO x enhancement was between 10 and 35 ppbv and was halved after 2 weeks. Ozone shows depletion signatures associated with both HO x (H + OH + HO 2 ) and NO x enhancements but at different timescales. Arctic lower mesospheric (upper stratospheric) ozone is reduced by 50–70% (30–40%) for about 2 weeks after the SPEs. A smaller ozone depletion signal was observed in the Antarctic atmosphere. After the locally produced Arctic middle and upper stratospheric as well as mesospheric NO x enhancement, large amounts of NO x were observed until the end of December. These are explained by downward transport processes. These enhancements drastically declined with the mid‐December stratospheric warming. Significant O 3 depletion was observed inside the polar vortex in a wide altitude range during this period. From mid‐January until the end of March 2004, MIPAS observed extraordinary high values of NO 2 in the upper stratosphere of the northern polar region (mean in‐vortex values up to 350 ppbv at ∼54 km), which seem to be caused by the unusually strong vortex and downward transport at that time together with an uncommonly large auroral activity starting with the solar storms in October–November and continuing over the winter. In‐vortex ozone was observed to significantly decline in the mid‐February to late March period above the 1750 K potential temperature level.