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| Titel |
North Atlantic meridional overturning circulation in a 1000-year climate model |
| VerfasserIn |
J. Williams, C. W. Hughes, R. J. Bingham |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025591
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| Zusammenfassung |
| The North Atlantic meridional overturning circulation (MOC) is important for ocean heat
transport in the Atlantic, so it is widely monitored and modelled. Previous work based on a
few decades of model simulations has shown that the overturning north of about 40-N is
quite different from that further south, and that changes in the circulation can be accurately
monitored using pressure measurements at the western boundary, and reasonably well
using tide gauge data. Here, we extend these analyses to 1000 years of data from
the HADCM3 climate model Control run. In the northern band we find a decadal
mode of variability, whilst to the south higher frequencies dominate, and the signal
becomes coherent with the northern mode (with a few years lag) only at periods
longer than about 10 years. In the deeper waters, especially at lower latitude and for
the first few centuries of the model run, the signal is dominated by longer term
trends. There is initially a strong increasing trend in the deep water overturning
cell, which stabilises after several centuries. Spatial patterns associated with the
transient are quite different from those produced by natural variability later in the
run. |
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