Methods for Estimating the Wind Climate Using The MIUU-model

Sammanfattning: In the year 2002 the Swedish Energy Agency assigned the department of Earth science at Uppsala University a research assignment to make a detailed wind climatology mapping covering Sweden. A survey of the Swedish wind climate has been made earlier in some areas, using the Danish model WASP. In this study the MIUU-model is usedwhich is a mesoscale three dimensional numerical model with a turbulence closure scheme of level 2.5. The MIUU-model is computer time demanding. Therefore a method to minimize the total number of simulations is wanted, without negative effects on the result. In this thesis the main issue is to compare the sensitivities and differences between climatological wind calculations using runs with different forcing parameters, i.e. with different meteorological conditions. Primarily the climatological results received with different geostrophic wind forcing are studied and compared. The idea is to find combinations with as small deviations as possible. The parameters investigated, called flow forcing parameters, are; geostrophic wind (magnitude and direction), thermal wind and thermal stratification. To compare the calculations a reference run is used. In theruns studying the influence of the geostrophic wind, calculations where made with 1, 2, 3 and 6 geostrophic wind speeds and with 4, 8, 16 and 32 wind directions. All compared to the reference that is based on 3 wind speeds and 8 wind directions. The model has earlier been used without any thermal wind influence. Therefore radio sonde data have been used to calculate the geostrophic mean wind profile introduced in the model to make new runs. The thermal stratification has also been modified in April and October to find out the sensitivities in the model. The result shows that there are only a few possible shortcuts in the number of runs needed and in the verification of the parameters. The question is if it is worth searching for them, since they might not be valid in other areas with more complex terrain. To be on the safe side, runs like the reference runs should at least be used in order to get accurate results as regards the wind climate.