Variability in the air–sea interaction patterns and timescales within the south-eastern Bay of Biscay, as observed by HF radar data

[摘要] Two high-frequency (HF) radar stations were installed on the coast of thesouth-eastern Bay of Biscay in 2009, providing high spatial and temporalresolution and large spatial coverage of currents in the area for the firsttime. This has made it possible to quantitatively assess the air–seainteraction patterns and timescales for the period 2009–2010. Theanalysis was conducted using the Barnett–Preisendorfer approach tocanonical correlation analysis (CCA) of reanalysis surface winds and HFradar-derived surface currents. The CCA yields two canonical patterns: thefirst wind–current interaction pattern corresponds to the classical Ekmandrift at the sea surface, whilst the second describes ananticyclonic/cyclonic surface circulation. The results obtained demonstratethat local winds play an important role in driving the upper watercirculation. The wind–current interaction timescales are mainly relatedto diurnal breezes and synoptic variability. In particular, the breezesforce diurnal currents in waters of the continental shelf and slope of thesouth-eastern Bay. It is concluded that the breezes may force diurnalcurrents over considerably wider areas than that covered by the HF radar,considering that the northern and southern continental shelves of the Bayexhibit stronger diurnal than annual wind amplitudes.

[学科分类] 海洋学与技术