 |
| Titel |
Recent changes in north-west Greenland climate documented by NEEM shallow ice core data and simulations, and implications for past-temperature reconstructions |
| VerfasserIn |
V. Masson-Delmotte, H. C. Steen-Larsen, P. Ortega, D. Swingedouw, T. Popp, B. M. Vinther, H. Oerter, Á. E. Sveinbjörnsdóttir, H. Gudlaugsdottir, J. E. Box, S. Falourd, X. Fettweis, H. Gallée, E. Garnier, V. Gkinis, J. Jouzel, A. Landais, B. Minster, N. Paradis, A. Orsi, C. Risi, M. Werner, J. W. C. White |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1994-0416
|
| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 9, no. 4 ; Nr. 9, no. 4 (2015-08-06), S.1481-1504 |
| Datensatznummer |
250116829
|
| Publikation (Nr.) |
 copernicus.org/tc-9-1481-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Combined records of snow accumulation rate, δ18O and deuterium
excess were produced from several shallow ice cores and snow pits at NEEM
(North Greenland Eemian Ice Drilling), covering the period from 1724 to 2007. They are used
to investigate recent climate variability and characterise the
isotope–temperature relationship. We find that NEEM records are only weakly
affected by inter-annual changes in the North Atlantic Oscillation. Decadal
δ18O and accumulation variability is related to North Atlantic
sea surface temperature and is enhanced at the beginning of the 19th century. No long-term
trend is observed in the accumulation record. By contrast, NEEM δ18O
shows multidecadal increasing trends in the late 19th
century and since the 1980s. The strongest annual positive δ18O
values are recorded at NEEM in 1928 and 2010, while maximum accumulation
occurs in 1933. The last decade is the most enriched in δ18O
(warmest), while the 11-year periods with the strongest depletion (coldest)
are depicted at NEEM in 1815–1825 and 1836–1846, which are also the driest
11-year periods. The NEEM accumulation and δ18O records are
strongly correlated with outputs from atmospheric models, nudged to
atmospheric reanalyses. Best performance is observed for ERA reanalyses.
Gridded temperature reconstructions, instrumental data and model outputs at
NEEM are used to estimate the multidecadal accumulation–temperature and
δ18O–temperature relationships for the strong warming period in
1979–2007. The accumulation sensitivity to temperature is estimated at
11 ± 2 % °C−1 and the δ18O–temperature
slope at 1.1 ± 0.2 ‰ °C−1, about
twice as large as previously used to estimate last interglacial temperature
change from the bottom part of the NEEM deep ice core. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|