Análisis de componentes principales de los vientos superficiales sobre la bahía de todos santos.

Abstract

Surface wind data, from four meteorological stations in Todos Santos Bay, are analyzed to study the local wind field. Statistical, rotary spectra, and principal components analysis (EOF) are used to describe the characteristics of the air flow. Diurnal and semidiurnal frequencies show the highest energies, giving evidence of the sea-land breeze and free convection processes. A time lag of the order of two hours in the initiation of the sea-breeze over the island site with respect to the shoreline stations is observed. The highest energy, in the diurnal frequency, is found in the island data, and the smallest energy for the city station showing the importance of friction. On the other hand, the highest energy occurs at semidiurnal frequencies over the city station and the weakest energy occurs over the island site, indicating the importance of convection and ground heating over the land as compared with the ocean. The EOF analysis shows that the principal eigenvectors are influenced by the synoptic wind, giving a southward component superimposed on the expected sea-land breeze eigenvectors normal to the coastline. The sea-breeze is, on the average, twice as strong as the land-breeze, moreoever, the sea-breeze is much more persistent than the land-breeze.