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| Titel |
Spatial regression analysis on 32 years of total column ozone data |
| VerfasserIn |
J. S. Knibbe, R. J. van der A, A. T. J. de Laat |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 16 ; Nr. 14, no. 16 (2014-08-22), S.8461-8482 |
| Datensatznummer |
250118966
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| Publikation (Nr.) |
 copernicus.org/acp-14-8461-2014.pdf |
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| Zusammenfassung |
Multiple-regression analyses have been performed on 32 years of total ozone
column data that was spatially gridded with a 1 × 1.5°
resolution. The total ozone data consist of the MSR (Multi Sensor
Reanalysis; 1979–2008) and 2 years of assimilated SCIAMACHY (SCanning
Imaging Absorption spectroMeter for Atmospheric CHartographY) ozone data
(2009–2010). The two-dimensionality in this data set allows us to perform
the regressions locally and investigate spatial patterns of regression
coefficients and their explanatory power. Seasonal dependencies of ozone on
regressors are included in the analysis.
A new physically oriented model is developed to parameterize stratospheric
ozone. Ozone variations on nonseasonal timescales are parameterized by
explanatory variables describing the solar cycle, stratospheric aerosols,
the quasi-biennial oscillation (QBO), El Niño–Southern Oscillation (ENSO) and stratospheric
alternative halogens which are parameterized by the effective equivalent
stratospheric chlorine (EESC). For several explanatory variables, seasonally
adjusted versions of these explanatory variables are constructed to account
for the difference in their effect on ozone throughout the year. To account
for seasonal variation in ozone, explanatory variables describing the polar
vortex, geopotential height, potential vorticity and average day length are
included. Results of this regression model are compared to that of a similar
analysis based on a more commonly applied statistically oriented model.
The physically oriented model provides spatial patterns in the regression
results for each explanatory variable. The EESC has a significant depleting
effect on ozone at mid- and high latitudes, the solar cycle affects ozone
positively mostly in the Southern Hemisphere, stratospheric aerosols affect
ozone negatively at high northern latitudes, the effect of QBO is positive
and negative in the tropics and mid- to high latitudes, respectively, and ENSO
affects ozone negatively between 30° N and 30° S,
particularly over the Pacific. The contribution of explanatory variables
describing seasonal ozone variation is generally large at mid- to high
latitudes. We observe ozone increases with potential vorticity and day
length and ozone decreases with geopotential height and variable ozone effects
due to the polar vortex in regions to the north and south of the polar
vortices.
Recovery of ozone is identified globally. However, recovery rates and
uncertainties strongly depend on choices that can be made in defining the
explanatory variables. The application of several trend models, each with their
own pros and cons, yields a large range of recovery rate estimates. Overall
these results suggest that care has to be taken in determining ozone
recovery rates, in particular for the Antarctic ozone hole. |
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