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キーワード:
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要旨:
Coastal sea-level trends in the Baltic Sea display decadal-scale variations around a long-term centennial
trend. In this study, we analyse the spatial and temporal characteristics of the decadal trend variations
and investigate the links between coastal sea-level trends and atmospheric forcing on a decadal timescale. For
this analysis, we use monthly means of sea-level and climatic data sets. The sea-level data set is composed of
long tide gauge records and gridded sea surface height (SSH) reconstructions. Climatic data sets are composed
of sea-level pressure, air temperature, precipitation, evaporation, and climatic variability indices. The analysis
indicates that atmospheric forcing is a driving factor of decadal sea-level trends. However, its effect is geographically
heterogeneous. This impact is large in the northern and eastern regions of the Baltic Sea. In the southern
Baltic Sea area, the impacts of atmospheric circulation on decadal sea-level trends are smaller.
To identify the influence of the large-scale factors other than the effect of atmospheric circulation in the same
season on Baltic Sea sea-level trends, we filter out the direct signature of atmospheric circulation for each season
separately on the Baltic Sea level through a multivariate linear regression model and analyse the residuals of
this regression model. These residuals hint at a common underlying factor that coherently drives the decadal
sea-level trends in the whole Baltic Sea. We found that this underlying effect is partly a consequence of decadal
precipitation trends in the Baltic Sea basin in the previous season.
The investigation of the relation between the AMO index and sea-level trends implies that this detected underlying
factor is not connected to oceanic forcing driven from the North Atlantic region.
