Biogeochemical and hydrographic observational data of the Northwest-European Shelf represent one of the most detailed sets of information available for the world shelf seas. This statement was true in 1996 (Laane et al., 1996) but still holds in these days. Since the late 1990ies a large amount of new data were collected in different data centers.
In this first stage of this climatology we concentrate on observations of the nutrients nitrate, ammonium, phosphate and silicate as well as of oxygen and chlorophyll. These six parameters describe the condition of the lower trophic marine ecosystem which shows significant spatial and temporal variations due to global changes and direct anthropogenic impact. Observations of temperature and salinity are also considered if recorded simultaneously with the biogeochemical parameters. In a second stage, carbonate system species and suspended matter will be added.
The idea of the existing data collection is to soundly represent the chosen parameters in space and time. Outliers in the observations originating, for example, from difficulties of the measurement equipment are caught by an extensive quality control procedure and ignored to the best of knowledge. Real outliers describing only a marginal phenomenon are also ignored by our methods.
The sampling density of the observations directly defines the temporal and spatial resolution to which mapping of the parameters seems reasonable. This implies a trade-off between temporal and spatial coverage.
At the moment, the climatology made available for the scientific community consists of maps of monthly, climatological monthly and all data mean parameter values for the period 1960-2014. This work was partly funded by the Cluster of Excellenc3 ‘CliSAP’ (EXC177), Universität Hamburg, funded by the German Science Foundation (DFG).