Strong winds in a coupled wave–atmosphere model during a North Atlantic storm event: evaluation against observations

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Pineau‐Guillou, Lucia, Ardhuin, Fabrice, Bouin, Marie‐Noëlle, Redelsperger, Jean‐Luc, Chapron, Bertrand, Bidlot, Jean‐Raymond, Quilfen, Yves
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2018
• Subjects: North Atlantic
• Online Access: http://dx.doi.org/10.1002/qj.3205; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.3205; https://onlinelibrary.wiley.com/doi/pdf/10.1002/qj.3205; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/qj.3205; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.3205

Strong winds may be biased in atmospheric models. Here the European Centre for Medium‐range Weather Forecasts ( ECMWF) coupled wave–atmosphere model is used (i) to evaluate strong winds against observations, and (ii) to test how alternative wind stress parametrizations could lead to a more accurate model. For the period of storms Kaat and Lilli (23–27 January 2014), we compared simulated winds with in situ – moored buoys and platforms – and satellite observations available from the North Atlantic. Five wind stress parametrizations were evaluated. The first result is that moderate simulated winds (5–20 m s −1 ) match with all observations. However, for strong winds (above 20 m s −1 ), mean differences appear, as much as −7 m s −1 at 30 m s −1 . Significant differences also exist between observations, with buoys and Advanced Scatterometer ASCAT‐KNMI generally showing lower wind speeds than the platforms and other remote‐sensing data used in this study ( AMSR2 , ASCAT‐RSS , WindSat , SMOS and JASON ‐2). Buoy and ASCAT‐KNMI winds are likely to underestimate the real wind speed. It is difficult to conclude which dataset should be used as a reference. The second result is that common wave‐age dependent parametrizations produce unrealistic drags and are not appropriate for coupling, whereas a newly empirically adjusted Charnock parametrization leads to higher winds compared to the default ECMWF parametrization. This proposed new parametrization may lead to more accurate results in an operational context.