Published online by Cambridge University Press: 11 May 2009
A model has been used to assess the relative importance of the various factors contributing to changes in the salinity of the eastern English Channel between 1948 and 1973. As part of the data input to the model, monthly means (1948–73) of total runoff into the eastern English Channel and monthly estimates of evaporation and precipitation for the same area (1961–73) were calculated. The results of this study have shown that river runoff is an important factor contributing to the variability of salinity in the eastern English Channel; rainfall over and evaporation from the Channel may also be important at certain times. The model can predict satisfactorily more than 80% of the variation of salinity from local data inputs. While Atlantic water movements and salinities may contribute to variability at the entrance to the English Channel, variations of flow through the Channel, caused by local wind forcing or originating further out in the Atlantic, have little effect on the fluctuations of salinity in the eastern English Channel. Furthermore, fluctuations in the salinity of the North Atlantic do not correspond to those observed at the entrance to the English Channel. River runoff and mixing due to the wind and tides appear to be the main factors responsible for the seasonal changes of salinity in the eastern English Channel.