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| Titel |
A multi-variable box model approach to the soft tissue carbon pump |
| VerfasserIn |
A. M. Boer, A. J. Watson, N. R. Edwards, K. I. C. Oliver |
| 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 ; 6, no. 6 ; Nr. 6, no. 6 (2010-12-21), S.827-841 |
| Datensatznummer |
250003852
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| Publikation (Nr.) |
 copernicus.org/cp-6-827-2010.pdf |
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| Zusammenfassung |
| The canonical question of which physical, chemical or biological mechanisms
were responsible for oceanic uptake of atmospheric CO2 during the last
glacial is yet unanswered. Insight from paleo-proxies has led to a multitude
of hypotheses but none so far have been convincingly supported in three
dimensional numerical modelling experiments. The processes that influence
the CO2 uptake and export production are inter-related and too complex
to solve conceptually while complex numerical models are time consuming and
expensive to run which severely limits the combinations of mechanisms that
can be explored. Instead, an intermediate inverse box model approach of the
soft tissue pump is used here in which the whole parameter space is
explored. The glacial circulation and biological production states are
derived from these using proxies of glacial export production and the need
to draw down CO2 into the ocean. We find that circulation patterns
which explain glacial observations include reduced Antarctic Bottom Water
formation and high latitude upwelling and mixing of deep water and to a
lesser extent reduced equatorial upwelling. The proposed mechanism of
CO2 uptake by an increase of eddies in the Southern Ocean, leading to a
reduced residual circulation, is not supported. Regarding biological
mechanisms, an increase in the nutrient utilization in either the equatorial
regions or the northern polar latitudes can reduce atmospheric CO2 and
satisfy proxies of glacial export production. Consistent with previous
studies, CO2 is drawn down more easily through increased productivity
in the Antarctic region than the sub-Antarctic, but that violates
observations of lower export production there. The glacial states are more
sensitive to changes in the circulation and less sensitive to changes in
nutrient utilization rates than the interglacial states. |
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