.Ocean Modelling for Beginners Phần 8 potx

122 6 Rotational Effects

diffusion are disabled. The TDV Superbee advection scheme is used for both the

nonlinear terms and in the vertically integrated continuity equation.

6.3.3 Results

Figure 6.1 shows the propagation of a coastal Kelvin wave attaining maximal

amplitude at the coast and showing an exponential decrease in amplitude away from

the coast. Numerical diffusion is apparent resulting in a decrease of wave amplitude

along the coast. Storm surges can stimulate such coastal Kelvin waves in shelf seas

of horizontal dimensions exceeding the Rossby radius of deformation. The North

Sea is one example of this.

Fig. 6.1 Exercise 15. Snapshot of the deformation of the sea surface caused by a coastal Kelvin

wave in the northern hemisphere

6.3.4 Sample Codes and Animation Script

The folder “Exercise 15” on the CD-ROM contains the computer codes for this

exercise.

6.3.5 Additional Exercise for the Reader

Repeat this exercise with different values of the Coriolis parameter and total water

depth and explore the resultant wave patterns. The reader might also introduce some

bottom friction.

6.4 Geostrophic Flow

6.4.1 Scaling

If we use the Coriolis force for reference, we can defin various force ratios

that essentially compare different time scales. The temporal Rossby number (see