One-hundred-and-forty years of daily observations in a tidal inlet (Marsdiep)

From 1861 to 1962 daily observations of temperature and salinity were carried out in the Marsdiep tidal inlet near Den Helder. Since 1947 similar measurements have been made in the Marsdiep on the coast of the island of Texel. Monthly mean differences for temperature and salinity were determined from the overlapping years. With these differences the Den Helder series could be extended to a homogeneous series from 1861 until 2001. The seasonal and annual mean salinities and temperatures are presented. The years 1999 and 2000 were the two warmest since 1861, and 1996 was among the five coldest years. The mean annual temperatures reflect the West European climatic variability and are highly correlated with the annual mean air temperature in Den Helder. Ice winters with monthly mean temperatures below 0°C occur generally in winters with a low NAO index. The salinity shows a persistent decreasing tendency related to increased river discharge since the beginning of the observations.

Article from Marine Science Symposia Vol. 219 - "Hydrobiological variability in the ICES Area, 1990-1999", symposium held in Edinburgh, 8-10 August 2001. To access  the remaining articles please click on the keyword "MSS Vol. 219".