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| Titel |
Mechanisms controlling primary and new production in a global ecosystem model – Part II: The role of the upper ocean short-term periodic and episodic mixing events |
| VerfasserIn |
E. E. Popova, A. C. Coward, G. A. Nurser, B. Cuevas, T. R. Anderson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 2, no. 2 ; Nr. 2, no. 2 (2006-12-06), S.267-279 |
| Datensatznummer |
250000520
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| Publikation (Nr.) |
 copernicus.org/os-2-267-2006.pdf |
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| Zusammenfassung |
The use of 6 h, daily, weekly and monthly atmospheric forcing resulted in dramatically
different predictions of plankton productivity in a global 3-D coupled physical-biogeochemical
model.
Resolving the diurnal cycle of atmospheric variability by use of 6 h forcing,
and hence also diurnal variability in UML depth, produced the largest
difference, reducing predicted global primary and new production by 25% and
10% respectively relative to that predicted with daily and weekly forcing.
This decrease varied regionally, being a 30% reduction in equatorial areas
primarily because of increased light limitation resulting from deepening of the
mixed layer overnight as well as enhanced storm activity, and 25% at moderate
and high latitudes primarily due to increased grazing pressure resulting from
late winter stratification events. Mini-blooms of phytoplankton and zooplankton
occur in the model during these events, leading to zooplankton populations being
sufficiently well developed to suppress the progress of phytoplankton blooms. A
10% increase in primary production was predicted in the peripheries of the
oligotrophic gyres due to increased storm-induced nutrient supply end enhanced
winter production during the short term stratification events that are resolved
in the run forced by 6 h meteorological fields.
By resolving the diurnal cycle, model performance was significantly improved with respect to several
common problems: underestimated primary production in the oligotrophic gyres; overestimated primary
production in the Southern Ocean; overestimated magnitude of the spring bloom in the subarctic Pacific Ocean,
and overestimated primary production in equatorial areas. The result of using 6 h forcing on predicted ecosystem
dynamics was profound, the effects persisting far beyond the hourly timescale, and having major consequences for
predicted global and new production on an annual basis. |
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