Description
The energy input from the wind to the waves determines the growth of waves due to wind. In wave models,this is parameterised by a wind input source function. The third generation ocean wave model WAM currentlyparameterises the wind input according to Janssen (1991). However, this approach has some drawbacks. Forinstance, it overestimates the wave drag at high wind speeds, it assumes the existence of a logarithmic windprofile, which is only approximately correct within the wave boundary layer and it neither conserves momentumnor kinetic energy. To address these issues, the Wave Boundary Layer Model (WBLM, Du et al. (2017, 2019)) isimplemented in WAM. The WBLM improves the wind input source function by accounting for those conversa-tions and calculating the wind profile within the wave boundary layer, thereby linking the atmospheric and wavemodelling. This accordingly improves the estimation of the friction velocity and therefore also the wave inducedstress and the roughness length, which are key parameters in the calculation of the growth rate of the wind inputsource function. To match the input source function, the dissipation source term is re-calibrated following Du etal. (2019). The aim of this study is to assess the added value of using such a WBLM in WAM both in stand-alonemodel simulations of the wave model and in coupled simulations with the atmospheric model COSMO-CLM(CCLM). To do so, the output of a stand-alone simulation of the WAM model with the new input source functionand dissipation term is compared against the simulation results of the original source input and dissipation terms ofJanssen (1991). For the validation, in-situ measurements from the Global Telecommunication System (GTS) andremote sensing measurements from Sentinel-3A are used. In a second step, the WBLM is then used in two-waycoupled simulations within WAM-CCLM. Based on the simulation results it will be concluded what the addedvalue of the WBLM is and during which situations the use of the WBLM might be most important.Period | 10 Sept 2019 |
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Event title | 2019 Annual Meeting of the European Meteorological Society |
Event type | Conference |
Location | Copenhagen, DenmarkShow on map |