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4. Results
The method how to do the coupling can be done using
different methods and this has some impact on the response
of the atmosphere. In general are the higher wind speeds
slightly reduced when the feed-back of the waves are also
included. When correctly including the impact of swell
waves the momentum transport is significantly reduced, this
includes reduced turbulence in the atmosphere and has a
significant impact on heat fluxes as well as other secondary
parameters. Figure 4 shows the change precipitation patterns
modelled by the RCA model as mean difference for one year
when including swell compared to when not including swell.
Rutgersson, A., Smedman, A.-S., Högström, U. 2001: Use
of conventional stability parameters during swell. J.
Geophys. Res., 106 , 27,117-27,134.
Semedo, A., Sætra, Ø., Rutgersson, A., Kahma, K.,
Pettersson, H. 2009: Wave induced wind in the marine
boundary layer. J. Atmos. Sci. in press.
Smedman, A., Högström, U., Bergström, H., Rutgersson,
A., Kahma, K., and H. Pettersson 1999. A case-study of
air-sea interaction during swell conditions. J. Geophys.
Res., 104, 25,833-25,851.
Figure 4. Annual mean precipitation difference when
including swell and not including swell in the RCA
model. Figure from Carlsson et al (2009).
5. Conclusions
It is of importance to correctly represent the impact of the
surface roughness. Having correct description alters the
surface roughness, but may also change the pressure patterns
over the sea.
References
Carlsson B., A. Rutgersson and A. Smedman, 2009a :
Impact of swell on a regional atmospheric climate model.
Under revision in Tellus.
Carlsson B., A. Rutgersson and A. Smedman, 2009b :
Investigated the effect of including wave effects in the
process oriented model PROBE-Baltic. Accepted for publ. in
Bor. Env Res.
Jones, C. G., Willén, U., Ullerstig, A. and Hansson, U.
The Rossby Centre Regional Atmospheric Climate Model
Part I: Model Climatology and Performance for the Present
Climate over Europe. Ambio 33:4-5, 199-210.
Komen, G. J., L. Cavaleri, M. Donelan, K. Hasselmann and
P.A.E.M. Janssen, Dynamics and Modelling of Ocean
Waves. In: , Cambridge University Press, Cambridge
(1994), p. 512.