Presentations

Abstract

Introduction This work focuses on establishing weather-based criteria to determine the stability of the marine atmospheric boundary layer (MABL) for offshore wind modelling, as it significantly affects wind flow, turbulence, and wake dynamics. This work will allow us to develop high-resolution numerical models for predicting offshore wind flow, wake dynamics, and to generate high-resolution meteorological datasets. Methodology – Stability criteria A critical aspect of offshore wind modeling is the stability of the marine atmospheric boundary layer (MABL). Stratification plays a crucial role in determining wind speed, shear, veer, and turbulence intensity, with stable conditions leading to stronger winds at hub height, weaker turbulence, while unstable conditions promote higher turbulence (Shaw et al., 2022). To classify MABL stability, we use a temperature-based criterion derived from the difference between 2-meter air temperature (T2m) and sea surface temperature (SST). This choice is motivated by the fact that thermal stratification directly influences turbulence intensity, frictional coupling with the surface, and the development of wind shear and veer (Shaw et al, 2022). Using T2m-SST as a classification metric provides a straightforward, physically meaningful approach to assess stability, as it captures the dominant thermodynamic processes controlling offshore wind flow. This method aligns with findings from LiDAR-based observations (Debnath et al, 2021) which demonstrate the sensitivity of wind profiles and extreme wind shear events to temperature stratification. Preliminary Results and Industry Contribution A case study using data from ERA5 has been carried out in the North Sea to demonstrate the validity of this criterion. Our results demonstrate that MABL stability plays a crucial role in turbulence intensity, directly impacting energy production and wind farm efficiency. Key findings include: Stable conditions (T2 - SST > 2°C) lead to prolonged wake effects due to reduced turbulence, increasing energy losses in downstream turbines. Unstable conditions (T2 - SST