To determine the hydraulic boundary conditions for the design of coastal defence structures, hydraulic (wave, water level) models are forced by observation-based winds. Winds observed at land stations are first transformed to open-water winds and then into stress to drive the respective model. The translation to stress is done using a drag coefficient that is parametrised as a function of wind speed. At first sight all production runs have to be repeated if new research suggests a new drag parameterization to be used. A recent memorandum describes a method to avoid repeating these runs. We here evaluate that method, and at the same time assess the method to translate the land wind to open-water wind.
A. Sterl. Brief review of wind and drag transformations in WBI2017
KNMI number: TR-363, Year: 2018, Pages: 12