Browsing by Author "Miranda, Pedro"
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- Building a wind atlas for mainland Portugal using a weather type classificationPublication . Costa, Paula Silva; Estanqueiro, Ana; Miranda, PedroA weather type classification scheme was implemented for the construction of a wind atlas to mainland Portugal. This methodology produced 26 different weather types computed by geostrophic vorticity at mean sea level pressure. Applying a simple calculus scheme, it is possible to find the most likely representative day for each weather type if a meteorological database with wind data is available. Each selected day can be simulated by a mesoscale model (e.g.MM5) being possible to construct the final wind atlas through the sum of the simulated days, weighted by the respective frequency factor. In this paper, it is shown that the results obtained by the application of this classification scheme for mean wind and energy density fields are very similar to long term simulations.
- Development and validation of the Portuguese wind atlasPublication . Costa, Paula Silva; Miranda, Pedro; Estanqueiro, AnaA methodology to construct a wind potential atlas for mainland Portugal is presented. A long term simulation with the popular MM5 mesoscale weather model was made with a whole year of reanalysis data (1999 year) in order to compute a mean wind annual cycle. Results were corrected by an intra annual variability factor and compared with four reference wind masts monitored by INETI for 12 years for validation purposes. The results obtained in this work are expected to present the wind energy developers a first estimate of the wind potential in mainland Portugal. Other useful applications can also be considered such as Tourism, territory planning and management, among others.
- High resolution forecasts of wind in rough orography and in coastal conditionsPublication . Miranda, Pedro; Costa, Paula Silva; Antunes, C.; Ferreira, João P.; Valente, A.; Rodrigues, Álvaro; Estanqueiro, AnaThe increase of the share of wind energy in total electrical power requires the development of reliable forecasts of wind power at different time scales, from minutes to days, on a regional and national basis. That development is multidisciplinary, involving meteorological and engineering components. In the present stage, though, it is thought that for time scales beyond 3 hours, the largest improvements are expected from the meteorological side, if meteorological forecasts are able to deal with mesoscale flow. In this paper three case studies of mesoscale modeling are analyzed and compared against wind observations in sites selected for their high potential for wind energy. Two cases deal with flow in the Islands of Madeira and San Jorge (Azores), characterized by rough orography, where measurements were made at the top of elevated plateaus. In these two cases, the large scale flow is obtained from ECMWF analysis and the mesoscale flow is computed, for one summer and one winter month, with two mesoscale models at resolutions between 6 and 0.5 km. In the third case, one full year of simulationis Continental Portugal is performed at resolutions between 27 and 3km, using boundary conditions from the NCEP/NCAR reanalysis and the MM5 model. Results indicate the interest of high horizontal resolution for wind forecasts in complex terrain but also some difficulties in the representation of boundary layer effects in conditions of large thermal forcing.