Günther Radach & Jens Gekeler
Institut für Meereskunde, Universität Hamburg
Troplowitzstr. 7, D-22529 Hamburg, Germany

Abstract

During the years 1993 to 1996 the MAST project "North-west European Shelf Programme (NOWESP)" has compiled all available observations for nine key state variables, namely temperature, salinity, phosphate, nitrate, nitrite, ammonia, silicate, suspended particulate matter (SPM) and chlorophyll, for the north-west European shelf. One important aim of NOWESP was to derive spatial distributions for each month by merging all available data to construct climatological monthly mean distributions to picture the climatological annual cycle, disregarding possible trends, e.g. in the coastal areas. In these areas the horizontal distributions have a bias towards the last fifteen years of observation because of the trends and of the increasing number of observations, and the interpolated data are representative for the decade 1984 to 1993.

Maps of horizontal distributions of temperature and salinity and of the concentrations of the nutrients phosphate, nitrate, nitrite, ammonia and silicate, of SPM and of chlorophyll are presented here for the months February, May, August and November. The properties of a few interpolation methods are discussed and the method chosen, i.e. exponentially distance weighted interpolation, is compared to the other methods. More details and maps for every month are given in the corresponding technical report by Radach & Gekeler (1997b).

Key words: temperature, salinity, nutrients, SPM, chlorophyll, annual cycles, horizontal distributions, North Sea, north-west European shelf