 |
| Titel |
Global and regional sea surface temperature trends during Marine Isotope Stage 11 |
| VerfasserIn |
Y. Milker, R. Rachmayani, M. F. G. Weinkauf, M. Prange, M. Raitzsch, M. Schulz, M. Kucera |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 9, no. 5 ; Nr. 9, no. 5 (2013-10-02), S.2231-2252 |
| Datensatznummer |
250085227
|
| Publikation (Nr.) |
 copernicus.org/cp-9-2231-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Marine Isotope Stage (MIS) 11 (424–374 ka) was characterized by a
protracted deglaciation and an unusually long climatic optimum. It remains
unclear to what degree the climate development during this interglacial
reflects the unusually weak orbital forcing or greenhouse gas trends.
Previously, arguments about the duration and timing of the MIS11 climatic
optimum and about the pace of the deglacial warming were based on a small
number of key records, which appear to show regional differences. In order
to obtain a global signal of climate evolution during MIS11, we compiled a
database of 78 sea surface temperature (SST) records from 57 sites spanning
MIS11, aligned these individually on the basis of benthic (N = 28) or
planktonic (N = 31) stable oxygen isotope curves to a common time frame and
subjected 48 of them to an empirical orthogonal function (EOF) analysis. The
analysis revealed a high commonality among all records, with the principal
SST trend explaining almost 49% of the variability. This trend indicates
that on the global scale, the surface ocean underwent rapid deglacial
warming during Termination V, in pace with carbon dioxide rise, followed by
a broad SST optimum centered at ~410 kyr. The second EOF,
which explained ~18% of the variability, revealed the
existence of a different SST trend, characterized by a delayed onset of the
temperature optimum during MIS11 at ~398 kyr, followed by a
prolonged warm period lasting beyond 380 kyr. This trend is most
consistently manifested in the mid-latitude North Atlantic and Mediterranean
Sea and is here attributed to the strength of the Atlantic meridional
overturning circulation. A sensitivity analysis indicates that these results
are robust to record selection and to age-model uncertainties of up to 3–6 kyr,
but more sensitive to SST seasonal attribution and SST uncertainties
>1 °C. In order to validate the CCSM3 (Community
Climate System Model, version 3) predictive potential, the annual and
seasonal SST anomalies recorded in a total of 74 proxy records were compared
with runs for three time slices representing orbital configuration extremes
during the peak interglacial of MIS11. The modeled SST anomalies are
characterized by a significantly lower variance compared to the
reconstructions. Nevertheless, significant correlations between proxy and
model data are found in comparisons on the seasonal basis, indicating that
the model captures part of the long-term variability induced by astronomical
forcing, which appears to have left a detectable signature in SST trends. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|