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| Titel |
Northern Hemisphere spring snow cover variability and change over 1922–2010 including an assessment of uncertainty |
| VerfasserIn |
R. D. Brown, D. A. Robinson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 5, no. 1 ; Nr. 5, no. 1 (2011-03-16), S.219-229 |
| Datensatznummer |
250002282
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| Publikation (Nr.) |
 copernicus.org/tc-5-219-2011.pdf |
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| Zusammenfassung |
An update is provided of Northern Hemisphere (NH) spring (March, April) snow
cover extent (SCE) over the 1922–2010 period incorporating the new climate
data record (CDR) version of the NOAA weekly SCE dataset, with annual 95%
confidence intervals estimated from regression analysis and intercomparison
of multiple datasets. The uncertainty analysis indicates a 95% confidence
interval in NH spring SCE of ±5–10% over the pre-satellite period
and ±3–5% over the satellite era. The multi-dataset analysis shows
larger uncertainties monitoring spring SCE over Eurasia (EUR) than North
America (NA) due to the more complex regional character of the snow cover
variability and larger between-dataset variability over northern Europe and
north-central Russia.
Trend analysis of the updated SCE series provides evidence that NH spring
snow cover extent has undergone significant reductions over the past ~90 yr and that the rate of decrease has accelerated over
the past 40 yr. The rate of decrease in March and April NH SCE over the 1970–2010
period is ~0.8 million km2 per decade corresponding to a 7%
and 11% decrease in NH March and April SCE respectively from pre-1970
values. In March, most of the change is being driven by Eurasia (NA trends
are not significant) but both continents exhibit significant SCE reductions
in April.
The observed trends in SCE are being mainly driven by warmer air
temperatures, with NH mid-latitude air temperatures explaining ~50%
of the variance in NH spring snow cover over the 89-yr period analyzed.
However, there is also evidence that changes in atmospheric circulation
around 1980 involving the North Atlantic Oscillation and Scandinavian
pattern have contributed to reductions in March SCE over Eurasia. |
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