On gustiness and growth of ocean waves

The effect of gustiness on the growth of ocean waves in the WAM model, a third generation ocean wave model, is discussed. Two approaches are used. The first one, proposed in Janssen (1986), is based on an effective wind-input source term which is a function of the gustiness. The second approach uses random values of the wind speed and direction, distributed over a certain range around the average value. Time-limited growth curves are obtained, using the one point WAM model. It is found that for relative fluctuations in the wind of the order of 30%, the saturation value of the wave height is increased by some 10%.