 |
| Titel |
Search for evidence of trend slow-down in the long-term TOMS/SBUV total ozone data record: the importance of instrument drift uncertainty |
| VerfasserIn |
R. S. Stolarski, S. M. Frith |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 12 ; Nr. 6, no. 12 (2006-09-08), S.4057-4065 |
| Datensatznummer |
250004105
|
| Publikation (Nr.) |
 copernicus.org/acp-6-4057-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| We have developed a merged ozone data set (MOD) for the period October
1978 through June 2006 combining total ozone measurements (Version 8
retrieval) from the TOMS (Nimbus 7, Earth Probe) and SBUV/SBUV2 (Nimbus 7,
NOAA 9/11/16) series of satellite instruments. We use the MOD data set to
search for evidence of ozone recovery in response to the observed leveling
off of chlorine and bromine compounds in the stratosphere. A crucial step in
any time series analysis is the evaluation of uncertainties. In addition to
the standard statistical time series uncertainties, we evaluate the possible
instrument drift uncertainty for the MOD data set. We combine these two
sources of uncertainty and apply them to a cumulative sum of residuals
(CUSUM) analysis for trend slow-down. For the extra-polar mean between
60° S and 60° N, the apparent slow-down in trend is found to be
clearly significant if instrument uncertainties are ignored. When instrument
uncertainties are added, the slow-down becomes marginally significant at the
2σ level. For the mid-latitudes of the northern hemisphere (30° to 60° N)
the trend slow-down is highly significant at the 2σ
level, while in the southern hemisphere the trend slow-down has yet to meet
the 2σ significance criterion. The rate of change of
chlorine/bromine compounds is similar in both hemispheres, and we expect the
ozone response to be similar in both hemispheres as well. The asymmetry in
the trend slow-down between hemispheres likely reflects the influence of
dynamical variability, and thus a clearly statistically significant response
of total ozone to the leveling off of chlorine and bromine in the
stratosphere is not yet indicated. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|