A stratospheric NO2 climatology from Odin/OSIRIS limb-scatter measurements
Artikel i vetenskaplig tidskrift, 2007

A climatology of stratospheric nitrogen dioxide (NO2), in terms of mean and standard deviation, as a function of latitude (5° bins); altitude (10–46 km in 2 km bins); local solar time (24 h); and month is constructed based on the Odin/OSIRIS limb-scattering data from 2002–2005. The measured profiles, given at specific local solar times, are scaled to all 24 h using a photochemical box model. The Odin orbit gives near global coverage around the equinoxes and hemispheric coverage elsewhere, due to lack of sunlight. The mean NO2 field at a specific local solar time involves high concentrations in the polar summer, peaking at around 25 km, with a negative equatorward gradient. Distinct high levels between 40–50° latitude at 30 km in the winter/spring hemisphere are also found, associated with the so-called {Noxon-cliff}. The diurnal cycle reveals the lowest NO2 concentrations just after sunrise and steep gradients at twilight. The 1σ standard deviation is generally quite low, around 20%, except for winter and spring high latitudes, where values are well above 50% and stretch through the entire stratosphere, a phenomenon probably related to the polar vortex. It is also found that NO2 concentrations are log-normally distributed. Comparisons to a climatology based on data from a (REPROBUS) chemical transport model for the same time period reveal relative differences below 20% in general, which is comparable to the estimated OSIRIS systematic uncertainty. Clear exceptions are the polar regions in winter/spring throughout the atmosphere and equatorial regions below 25 km, where OSIRIS is relatively higher by 40% and more. These discrepancies are most likely attributable to limitations of the model, but this has to be investigated further.

Satellite Odin OSIRIS Climatology Limb scattering Stratosphere nitrogen dioxide

Författare

Samuel Brohede

Chalmers, Institutionen för radio- och rymdvetenskap, Global miljömätteknik

C. A. McLinden

Environment Canada

G. Berthet

CNRS Centre National de la Recherche Scientifique

C. S. Haley

York University

Donal Murtagh

Chalmers, Institutionen för radio- och rymdvetenskap, Global miljömätteknik

C. E. Sioris

Environment Canada

Canadian Journal of Physics

0008-4204 (ISSN) 1208-6045 (eISSN)

Vol. 85 11 1253-1274

Ämneskategorier

Fysikalisk kemi

Meteorologi och atmosfärforskning

Atom- och molekylfysik och optik

Fusion, plasma och rymdfysik

DOI

10.1139/P07-141