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© KNMI 2004
The Wave Modelling (WAM) Group
A historical perspective
Gerbrand Komen
BMRC, 6 december 2004
Klaus Hasselmann
Overview
1. Pre WAM
2. The WAM model and the Wave Modelling Group
(~1980 – 1994)
3. Post WAM
Pre - WAM
1. Pierson: wave spectrum
2. Gelci: dynamic equation
3. Hasselmann et al (JONSWAP): observations
4. Models, SWAMP
Giuseppe Santomaso
1907 - 1990
Pre - WAM
1. Pierson: wave spectrum
2. Gelci: dynamic equation
3. Hasselmann et al (JONSWAP): observations
4. Models, SWAMP
F = F (k, x, t )
cg = cg ( k )
Pre - WAM
1. Pierson: wave spectrum
2. Gelci: dynamic equation
3. Hasselmann et al (JONSWAP): observations
4. Models, SWAMP
scaling
Pre - WAM
1. Pierson: wave spectrum
2. Gelci: dynamic equation
3. Hasselmann et al (JONSWAP): observations
4. Models, SWAMP
Early models
GONO, HYPA, UKMO, . . .
For wind sea: use observed growth curves
to determine wave height from wind speed and
estimated wave age
Reconstruct spectral shape from scaling laws
Add swell
Validate
Intercompare -> SWAMP
The WAM model
The emergence of a 3rd generation models
1. The problem: Snl
2. Susanne Hasselmann Miami 1981, Exact NL
3. Hamburg 1983 , study the actual balance
omega = omega ( k ) = sqrt ( g k )
N ~ F
Webb, Matsuda, Hasselmann and Hasselmann . .
The emergence of a 3rd generation
models
1. The problem: Snl
2. Susanne Hasselmann Miami 1981, Exact NL
3. Hamburg 1983, study the actual balance
4. Sendai, 1984
The WAM group
1. Hamburg 1984
2. WAM = Wave Modelling group
- model implementation: global/regional
- growth curve reanalysis
- directional effects
- data assimilation of satellite observations
3. Funding: EU, ECMWF, SCOR
WAM
1. Source terms
- wind input, Charnock parameter
- nonlinear transfer
- dissipation/whitecapping
- shallow water effects
- current refraction, sea ice
2. Validation
3. Operational implementation
WAM
Outreach
Annual meetings (1984 - 1994)
Course on Ocean Waves and Tides (ICTP, 1988)
Dynamics and Modelling of Ocean Waves (1994)
Venice, 1985
KNMI, 1994
Post WAM
1. WISE (Leo Holthuijsen, Luigi Cavaleri)
2. Freak waves (Peter Janssen)
3. Probability Forecast ECMWF (Jean Bidlot et al)
4. BMRC (Diana Greenslade)
5. Decadal variability in global extreme statistics
(Sofia Caires, Andreas Sterl, Gerbrand Komen)
Post WAM
1. Probability Forecast ECMWF
2. BMRC (Diana Greenslade, Ian Young)
3. Decadal variability in global extreme statistics
Spatial scale of background errors in the model SWH (Diana Greenslade,BMRC)
Post WAM
1. Probability Forecast ECMWF
2. BMRC
3. Decadal variability in global extreme statistics
Summary
It was successful
It was fun:
- nice to work with all these people
- nice to understand ocean waves