Variability of the mixing zones and estuarine turbidity maxima in the Elbe and Weser estuaries

The neighboring coastal plain estuaries of the Elbe and Weser Rivers in Northern Germany exhibit pronounced estuarine turbidity maxima (ETM). Common features and differences between the longitudinal distributions of salinity and suspended particulate matter (SPM) in both estuaries are compared as well as the mechanisms effecting them. Monthly transects of the near surface SPM indicate that the long-term variability of salinity and the ETM is mainly influenced by the freshwater runoff. The variability is reduced to certain characteristic patterns by application of Empirical Orthogonal Functions analysis. The coefficients of these patterns are then correlated to runoff and the resulting functional regressions are used for the construction of a statistical model for the distribution of salinity and SPM along the estuaries; for SPM this has not been successful.