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《极地科学进展(英文版)》
>An ice-ocean model study to explore climate change mechanisms in comparison with interannual-to-decadal variability of geochemical tracers
An ice-ocean model study to explore climate change mechanisms in comparison with interannual-to-decadal variability of geochemical tracers
One way to identify the mechanisms that are crucial to Arctic climate change is to use existing data that exhibit interannual-to-decadal variability in the sea ice and ocean interior due to atmospheric forcing. Since around 1960s, valuable geochemical data of the ocean interior, together with atmospheric and sea ice data, have been analyzed and examined in a coupled ice–ocean model with an idealized configuration of the Arctic Basin. This is fundamentally driven by negative salt flux, in addition to atmospheric circulation and cooling. This strategy has a clear advantage over more sophisticated models with higher resolution that require extensive data collections for veriifcation. Around 1990, the dominant atmospheric mode shifted from the Northern Annular Mode (NAM) to the Arctic Dipole Mode (ADM). The variability of sea ice cover was explained by these two modes sequentially and reproduced in the model. In particular, the geochemical ifelds indicated a movement of the Transpolar Drift Stream due to the NAM and an oscillation of the Paciifc water between the Atlantic and Paciifc sides due to the ADM. Both these features were reproduced reasonably well by the oceanic tracers in the model, including the time lags of about one third of the oscillation periods. Thus, this strategy can suggest methods and locations for monitoring oceanographic responses to Arctic climate change.
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