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| Titel |
Greenland accumulation and its connection to the large-scale atmospheric circulation in ERA-Interim and paleoclimate simulations |
| VerfasserIn |
N. Merz, C. C. Raible, H. Fischer, V. Varma, M. Prange, T. F. Stocker |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 9, no. 6 ; Nr. 9, no. 6 (2013-11-04), S.2433-2450 |
| Datensatznummer |
250085252
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| Publikation (Nr.) |
 copernicus.org/cp-9-2433-2013.pdf |
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| Zusammenfassung |
| Changes in Greenland accumulation and the stability in the relationship
between accumulation variability and large-scale circulation are assessed by
performing time-slice simulations for the present day, the preindustrial era, the
early Holocene, and the Last Glacial Maximum (LGM) with a comprehensive
climate model. The stability issue is an important prerequisite for
reconstructions of Northern Hemisphere atmospheric circulation variability
based on accumulation or precipitation proxy records from Greenland ice
cores. The analysis reveals that the relationship between accumulation
variability and large-scale circulation undergoes a significant seasonal
cycle. As the contributions of the individual seasons to the annual signal
change, annual mean accumulation variability is not necessarily related to
the same atmospheric circulation patterns during the different climate
states. Interestingly, within a season, local Greenland accumulation
variability is indeed linked to a consistent circulation pattern, which is
observed for all studied climate periods, even for the LGM. Hence, it would
be possible to deduce a reliable reconstruction of seasonal atmospheric
variability (e.g., for North Atlantic winters) if an accumulation or
precipitation proxy were available that resolves single seasons. We further
show that the simulated impacts of orbital forcing and changes in the
ice sheet topography on Greenland accumulation exhibit strong spatial
differences, emphasizing that accumulation records from different ice core
sites regarding both interannual and long-term (centennial to millennial)
variability cannot be expected to look alike since they include a distinct
local signature. The only uniform signal to external forcing is the strong
decrease in Greenland accumulation during glacial (LGM) conditions and an
increase associated with the recent rise in greenhouse gas concentrations. |
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