Surface wind regionalization in complex terrain

© 2008 American Meteorological Society. We thank the Sección de Evaluación de Recursos Agrarios del Departamento de Agricultura, Ganadería y Alimentación of the Navarra Government for providing us with the wind dataset used in this study and the ECMWF for the free access to the ERA-40 data. We also thank Drs. M. Montoya and C. Raible for useful discussions, suggestions, and comments during this work, as well as Prof. M. Cornide for providing a first version of the code to calculate the spectral densities. The authors are indebted to the three reviewers for their comments, which helped to improve the quality of the original manuscript considerably. This work was partially funded by Project CGL2005- 06966-C07/CLI. JFGR was supported by a Ramón y Cajal fellowship.
Daily wind variability in the Comunidad Foral de Navarra in northern Spain was studied using wind observations at 35 locations to derive subregions with homogeneous temporal variability. Two different methodologies based on principal component analysis were used to regionalize: 1) cluster analysis and 2) the rotation of the selected principal components. Both methodologies produce similar results and lead to regions that are in general agreement with the topographic features of the terrain. The meridional wind variability is similar in all subregions, whereas zonal wind variability is responsible for differences between them. The spectral analysis of wind variability within each subregion reveals a dominant annual cycle and the varying presence of higher-frequency contributions in the subregions. The valley subregions tend to present more variability at high frequencies than do higher-altitude sites. Last, the influence of large-scale dynamics on regional wind variability is explored by studying connections between wind in each subregion and sea level pressure fields. The results of this work contribute to the characterization of wind variability in a complex terrain region and constitute a framework for the validation of mesoscale model wind simulations over the region.
Programa Ramón y Cajal (MEC)
Ministerio de Educación y Ciencia (MEC), España
Depto. de Física de la Tierra y Astrofísica
Fac. de Ciencias Físicas
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