 |
| Titel |
Extreme ozone depletion in the 2010–2011 Arctic winter stratosphere as observed by MIPAS/ENVISAT using a 2-D tomographic approach |
| VerfasserIn |
E. Arnone, E. Castelli, E. Papandrea, M. Carlotti, B. M. Dinelli |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 19 ; Nr. 12, no. 19 (2012-10-10), S.9149-9165 |
| Datensatznummer |
250011499
|
| Publikation (Nr.) |
 copernicus.org/acp-12-9149-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| We present observations of the 2010–2011 Arctic winter stratosphere from the
Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard
ENVISAT. Limb sounding infrared measurements were taken by MIPAS during the
Northern polar winter and into the subsequent spring, giving a continuous
vertically resolved view of the Arctic dynamics, chemistry and polar
stratospheric clouds (PSCs). We adopted a 2-D tomographic retrieval approach
to account for the strong horizontal inhomogeneity of the atmosphere present
under vortex conditions, self-consistently comparing 2011 to the 2-D analysis
of 2003–2010. Unlike most Arctic winters, 2011 was characterized by a strong
stratospheric vortex lasting until early April. Lower stratospheric
temperatures persistently remained below the threshold for PSC formation,
extending the PSC season up to mid-March, resulting in significant chlorine
activation leading to ozone destruction. On 3 January 2011, PSCs were
detected up to 30.5 ± 0.9 km altitude, representing the highest PSCs
ever reported in the Arctic. Through inspection of MIPAS spectra, 83% of
PSCs were identified as supercooled ternary solution (STS) or STS mixed with
nitric acid trihydrate (NAT), 17% formed mostly by NAT particles, and only
two cases by ice. In the lower stratosphere at potential temperature 450 K,
vortex average ozone showed a daily depletion rate reaching
100 ppbv day−1. In early April at 18 km altitude, 10% of vortex
measurements displayed total depletion of ozone, and vortex average values
dropped to 0.6 ppmv. This corresponds to a chemical loss from early winter
greater than 80%. Ozone loss was accompanied by activation of ClO,
associated depletion of its reservoir ClONO2, and significant
denitrification, which further delayed the recovery of ozone in spring. Once
the PSC season halted, ClO was reconverted primarily into ClONO2. Compared
to MIPAS observed 2003–2010 Arctic average values, the 2010–2011 vortex in
late winter had 15 K lower temperatures, 40% lower HNO3 and 50%
lower ozone, reaching the largest ozone depletion ever observed in the
Arctic. The overall picture of this Arctic winter was remarkably closer to
conditions typically found in the Antarctic vortex than ever observed before. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|