Estimation of offshore extreme wind from wind‐wave coupled modeling

Abstract

A coupledwind‐wave modeling system is used to simulate 23 years of storms and estimate offshore extreme wind statistics. In this system, the atmospheric Weather Research and Forecasting (WRF) model and Spectral Wave model for Near shore (SWAN) are coupled, through a wave boundary layer model (WBLM) that is implemented in SWAN. The WBLM calculates momentum and turbulence kinetic energy budgets, using them to transfer wave‐induced stress to the atmospheric modeling. While such coupling has a trivial impact on the wind modeling for 10‐m wind speeds less than 20 ms−1, the effect becomes appreciable for stronger winds—both compared with uncoupled WRF modeling and with standard parameterization schemes for roughness length. The coupled modeling output is shown to be satisfactory compared with measurements, in terms of the distribution of surface‐drag coefficient with wind speed. The coupling is also shown to be important for estimation of extreme winds offshore, where the WBLM‐coupled results match observations better than results from noncoupled modeling, as supported by measurements from a number of stations.

Impact of Air–Wave–Sea Coupling on the Simulation of Offshore Wind and Wave Energy Potentials

“…However, the wave influences cannot be captured by a stand-alone atmospheric model through tuning model parameterizations [14]. Twenty-three years storms are simulated using an atmosphere-wave-coupled model, Larsen et al [15] found that the coupled model improves the wind simulation considerably when compared with the measurements from five offshore sites around Denmark, in particular when the mean wind speed at 10 m U 10 > 20 m s −1 . On the low wind and swell conditions, the wind simulation is improved when sea-state-dependent wind stress parameterization is implemented into an atmosphere-wave-coupled system [12].…”

Mapping wind resources and extreme wind: Technical and social aspects

“…Liu et al 2011, Wu et al 2015. Larsén et al (2019) used a wind-wave coupled system to draw up an extreme-wind atlas for the waters around Denmark. In general, there is still the challenge of too few measurements being available offshore, making it difficult to validate and improve modelling approaches.…”

Approaches toward improving the modelling of midlatitude cyclones entering at the lateral boundary corner in the limited area WRF model

“…(2017a) and Larsén et al . (2019), which showed good performance when simulating storms events. Sea surface temperature is not updated during the simulation.…”

“…In studies such as that of Larsén et al . (2019), which focuses on the estimation of extreme offshore wind speeds, correctly simulating both the intensity and the location of hundreds of storms is crucial for reliable statistics. Therefore, careful design of the LAM settings is required.…”