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| Titel |
On the possibilities to use atmospheric reanalyses to evaluate the warming structure in the Arctic |
| VerfasserIn |
C. E. Chung, H. Cha, T. Vihma, P. Räisänen, D. Decremer |
| 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 ; 13, no. 22 ; Nr. 13, no. 22 (2013-11-18), S.11209-11219 |
| Datensatznummer |
250085821
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| Publikation (Nr.) |
 copernicus.org/acp-13-11209-2013.pdf |
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| Zusammenfassung |
There has been growing interest in the vertical structure of the recent
Arctic warming. We investigated temperatures at the surface, 925, 700, 500
and 300 hPa levels in the Arctic (north of 70° N) using
observations and four reanalyses: ERA-Interim, CFSR, MERRA and NCEP II. For
the period 1979–2011, the layers at 500 hPa and below show a warming trend
in all seasons in all the chosen reanalyses and observations. Restricting
the analysis to the 1998–2011 period, however, all the reanalyses show a
cooling trend in the Arctic-mean 500 hPa temperature in autumn, and this
also applies to both observations and the reanalyses when restricting the
analysis to the locations with available IGRA radiosoundings. During this
period, the surface observations mainly representing land areas surrounding
the Arctic Ocean reveal no summertime trend, in contrast with the
reanalyses whether restricted to the locations of the available surface
observations or not.
In evaluating the reanalyses with observations, we find that the reanalyses
agree better with each other at the available IGRA sounding locations than
for the Arctic average, perhaps because the sounding observations were
assimilated into reanalyses. Conversely, using the reanalysis data only from
locations matching available surface (air) temperature observations does not
improve the agreement between the reanalyses. At 925 hPa, CFSR deviates from
the other three reanalyses, especially in summer after 2000, and it also
deviates more from the IGRA radiosoundings than the other reanalyses do. The
CFSR error in summer T925 is due mainly to underestimations in the
Canadian-Atlantic sector between 120° W and
0°. The other reanalyses also have negative biases in this
longitude band. |
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