Validation of Evaporation Duct Model in Coastal Regions with ASIT Data

This study aims to further verify the evaporation duct (ED) model in a coastal region as well as the need for model localization based on the measurements from the Air-Sea Interaction Tower (ASIT). The ducts tended to be more frequent and pronounced in coastal offshore winds than in onshore winds, especially in case of combining unstable conditions (100% and 9.5 m/8.7 m). They occurred with the lowest frequency (56.4%) and thickness (4.9 m/3.5 m) in stable onshore winds. The ED model with psi functions of Edson04 (or Fairall03) and SHEBA07 delivered the best overall performance in terms of predicting local evaporation ducts. Its considerable advantages over the COARE 3.0 model and BYC model underscore the importance of localization to a given region. The overall performance of the localized ED model was encouraging but it encountered problems in case of extreme ducts under stable offshore conditions, when the available improvements to it failed. The reinforcement of a stable marine inner-boundary layer (MIBL) to a preexisting evaporation duct was considered the main reason for this and, hence, the future solution.