Abstract
A local, two-dimensional principal-component analysis has been applied to mesoscale winds in a region strongly influenced by topography. The principal components successfully separate axial winds over Puget Sound from cross-axial winds. Energy spectra of winter axial winds contain significant peaks at synoptic-scale periods of 1.5–5 days but also a strong peak of unknown origin at 17 days. Cross-axial winds are dominated by the land-sea breeze. Day-night asymmetries in the land-sea temperature contrast lead to diurnal modulation and energy at the semidiurnal period. The land breeze persists in winter over Puget Sound, but the sea breeze dominates a weakened land breeze in summer.
