Calculations on the wind climate in northern Finland: The importance of inversions and roughness variations during the seasons

The wind power potential around Pyhätunturi Fell in northern Finland is calculated with WAsP and the Karlsruhe Atmospheric Mesoscale Model (KAMM) using a climatology of the geostrophic wind from the global reanalysis of NCEP/NCAR. The importance of roughness variations between summer and winter due to snow cover and of strong, low-level 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 61 m. However, frequent inversions in winter have a major 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 350 m. This is too rough to resolve the steep slopes of Pyhätunturi Fell. Therefore the predicted wind speed on the summit is underestimated by up to 15% depending on the wind direction.

Copyright © 1999 John Wiley & Sons, Ltd.