On the representation of regional characteristics by hydrographic measurements at central stations in four deep basins of the Baltic Sea

[摘要] In this work the eddy resolving data sets of salinity, temperature, andoxygen content aquired in the framework of the German-Russian projectMESODYN (MESOscale DYNamics) in the Arkona Basin, the BornholmBasin, the Stolpe Furrow, and the Eastern Gotland Basin during summer andwinter stratification situations are utilized to examine to which extent theobservations at the central monitoring stations within these basins arerepresentative for the spatial mean state of the corresponding region withrespect to comparative monitoring purposes of the whole Baltic Sea. Theinvestigation covers profiles of salinity, potential temperature, oxygencontent, potential density, and squared buoyancy or Brunt-Väisäläfrequency. Moreover, some parameters of the halocline, namely its depth,thickness, and upper and lower boundaries, and the first baroclinic Rossbyradii are subject to the investigation. The profiles match best for thesquared buoyancy or Brunt-Väisälä frequency. The profiles ofsalinity match best in the Eastern Gotland Basin and worst in the ArkonaBasin both for summer and winter stratification situations. The overallagreement for the halocline parameters is good. The baroclinic Rossby radiimatch their spatial mean values well, if the depth range considered for theircalculation is restricted to the mean depth in each region at the bottomside. In doing so they also match the spatial mean values of the firstbaroclinic Rossby radii calculated considering the whole depth range at eachstation. Overall, the regional characteristics of the investigated quantitiesand parameters are represented well by the hydrographic measurements at thecentral stations in the four regions in spite of some significant differencesbetween the spatial mean states and the observations at the central stations.In particular, the observations at the central stations seem to be usefullfor comparisons between these regions. However, the observed differences mayaffect regional investigations covering just a single region.

[学科分类] 海洋学与技术