Calculations on the Wind Climate in Northern Finland: the Importance of Inversions and Roughness Variations during the Seasons

摘要

The wind power potential around Pyhatunturi Fell in northern Finland is calculated with WAsP and the Karlsruhe Atmospheric Mesoscale Model (KAMM) using a climatology of the geostrophic wind from the globol reanalysis of NCEP/NCAR. The importance of roughness variations between summer and winter due to snow cover and of strong, low- Ievel inversions during winter is investigated. At the position of a telemast on the fell the changing roughness led to an increase in the predicted wind power density of only 1 at 61m. However, frequent inversions in winter have a mojor influence on the wind potential on the fell areas. Accounting for them increased the predicted wind power density by 10-16, giving better agreement with the observations. As expected, the wind in the plains is reduced during conditions with inversions. The simulations with KAMM were performed for a grid map with a resolution of 350m. This is too rough to resolve the steep slopes of PyhAtunturi Fell. Therefore the predicted wind speed on the summit is underestimated by up to 15 depending on the wind direction.