**7. Conclusion**

124 Hydrodynamics – Natural Water Bodies

limited in space and time. In Fig. 4 we show a scatter plot of the predicted versus the observed temperature taken from a sea level measurement station located offshore near Hadera (see map in Fig. 2 for location). The instrument was located at a depth of ~15 m below the surface and the bottom depth is ~27 m. The comparison shown here also covers a one year period. Overall the comparison is excellent with a correlation coefficient of nearly 0.97. During winter (low temperatures) and summer (high temperatures) the points tend to be roughly evenly scatter above and below the regression line thus indicating that there is no clear bias in the forecasts. During the transition seasons of spring and autumn (mid range temperatures), there is a strong tendency for the model to under predict the temperature and therefore develop a cold bias. This is most likely due to the more rapid temperature

changes during the transitions seasons as compared to summer or winter.

Fig. 4. Scatter plot of the predicted versus measured temperature at a depth of 15 m at an

Finally, as a measure of the spatial distribution of the prediction of the subsurface fields, a comparison was made between all measurements collected during a single, one day cruise in the late summer along a transect of points that extend westward from Haifa (see Fig. 2 for location). The measurements were obtained from an instrument that measures nearly continuous profiles of temperature and salinity from the surface to the bottom or to a depth of 1000 m, whichever is deeper. From below the surface mixed layer, the model did an excellent job of predicting the temperature and salinity at all depths and stations along the transect. In the mixed layer the model showed a warm bias with simulated temperatures that were too high by 1-2°C. This error is probably due to the specification of surface heat fluxes that were too high and/or winds that were too weak which prevented the model from creating a deep enough mixed layer. The high resolution forecast was significantly better than the regional model forecast in this area which again demonstrates the value added by a high resolution model. It should be noted however that this comparison was

offshore station.

conducted for a single forecast only.

In this chapter we have presented a concise overview of more than 40 years of research and development of numerical ocean circulation models. The pioneering work of Bryan & Cox (1967) set the stage for subsequent model development. The rapid development of computer technology of the past two decades has been a major factor allowing for the design of increasingly more complex and realistic models. By complementing field data and the associated gaps, numerical ocean models have proven to be an indispensible tool for enhancing our understanding of a wide range and variety of processes in oceanic hydrodynamics. Consequently, most modern oceanographic studies will almost always include a highly developed modeling component. Models are routinely used for processes studies and as the central component operational ocean forecasting systems as demonstrated by the examples presented.
