Microsoft Word Report 11 02 Wave Power final ex appendix doc

Wave modelling 
Modelling waves is a quite tricky task since most of the processes that occur 
in the atmosphere and in the oceans are in some way interconnected. The 
flowchart below (Figure A.1) is an attempt to given an overview of the 
methodology behind wave modelling. 
Regional
model
– e.g.
SWAN,
MIKE21OSW
etc.
Wind
input
–
A
reanalysis
product
e.g.
ERA
Interim,
NCEP/NCAR
Topography
Waves – boundary conditions for 
the next modelling step 
S(f,
θ
,
t)
–
directional
spectrum
Wind
field
input
–
Reanalysis
data
Global
model
– e.g.
WAM,
WAVEWATCH
III
etc.
Waves – boundary conditions for the next 
modelling step. Number of step according to 
resolution demand 
Regional
model
– e.g.
SWAN,
MIKE21OSW
etc.
Wind
field
input
–
Reanalysis
data

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ELFORSK 
44 
Figure
 
A.1:
 
General
 
description
 
of
 
the
 
methodology
 
behind
 
wave
 
modelling.
 
Global model 
Even though only a site in e.g. the nearshore is of interest, a global wave 
model is needed in order to generate the boundary wave conditions needed as 
inputs to the regional wave model. This global model is fed with e.g. wind 
data, and since most of the grid points are deep-water locations the quality of 
the sea floor and depths data is not as crucial here as when the regional 
model is set up.