@inproceedings{VERLAAN96,

author = {M. Verlaan, J.J. Leendertse},

title = {Modelling of the Rhine Region of Freshwater Influence},

organization = {Wessex Institue of Technology},

year = {1996},

note = {abstract submitted},

annote = {In order to provide pilots guiding ships near the harbour in Rotterdam in the Netherlands with accurate current information a considerable effort has gone into the modelling of the region around the 'Nieuwe Waterweg'. Until several years ago, mainly one and two dimensional shallow water flow models were used for this. The results of the computations were usually processed into a current atlas, in which a map of the typical currents is given for every phase of the tide.

More recently it was recognized that the currents in this region to a large extend are influenced by the flow of fresh water from the Meuse and Rhine rivers and by the wind. This necessitates the on-line forecasting of the currents, since the number of possible combinations of wind and river outflow is simply too large to tabulate. Moreover, the clear three dimensional structure of the currents makes the use of a three dimensional model necessary.

In the present study a three dimensional model of the area was compared with a large set of measurements for various settings of the model parameters and using several turbulence models. The measurements include HF-radar measurements of surface currents and current and salinity measurements at various depths and positions. The results indicate that wind and stratification play an important role and that these effects can be modelled reasonably well using a three dimensional model.

Future research will aim at assimilating HF-radar surface current

measurements into the three dimensional model presented here using an efficient approximation of the time-varying Kalman filter. The data assimilation scheme is used then to correct the errors introduced by the computation of the wind stress on the water surface. Some experiments were performed to asses the feasibility of this procedure.}

}