Coupled ocean wind and sea surface temperature patterns off the western Iberian Peninsula Ricardo F. Sánchez a, ⁎ , Paulo Relvas b , Marina Delgado c a CIACOMAR/CIMA, University Algarve, Avda. 16 de Junho s/n Olhão 8700-311, Portugal b FCMA/CIMA, University Algarve. Campus de Gambelas s/n. 8000 Faro, Portugal c IRTA Crta. Poblenou s/n, 43540 St. Carles de la Ràpita (Tarragona), Spain Received 3 July 2005; received in revised form 8 June 2006; accepted 14 November 2006 Available online 4 January 2007 Abstract Atmosphere–ocean coupling off the western Iberian Peninsula (IP) was empirically explored using Canonical Correlation Analysis (CCA) of Sea Surface Temperatures (SST) and ocean winds. The analyses were performed at three different spatio-temporal levels: a) regional-scale, 1° × 1°, monthly data (1981–1997), b) mesoscale 0.25° × 0.25° winds with 4 km × 4 km SST, weekly data (1999–2002), and c) mesoscale 0.25° × 0.25° winds with 1 km × 1 km SST, daily data (summers 2000–2003). At the regional-scale most modes showed upwelling/downwelling patterns related to the North Atlantic Oscillation, and as such, much of the variability concentrated at quasi- biennial frequencies. Energy transfer from the regional-scale to the mesoscale was noted. On week-to-month timescales, the NAO index (expressed as the leading mode of the regional analysis) showed positive correlation with the number of upwelling filaments in summer and negative correlation with the intensity of the Iberian Current. The effects of Cape St. Vincent on the wind field were more evident over timescales of days to weeks. Although upwelling/downwelling patterns were also present at the mesoscale, a group of modes showed spatial heterogeneity of ocean winds close to the cape and SST patterns spatially not correlated with the wind vectors. One of the summer canonical modes highlighted the formation of a westward upwelling filament from Cape St. Vincent in response to a spatially sheared wind field. The evolution of warm inshore counter-current opposing to the wind close to Cape St. Vincent was noted. Using these results, mechanisms other than wind forcing were considered responsible for thermal patterns over timescales of days-to-weeks. The main conclusion is that Cape St. Vincent plays a dominant role in the configuration of wind forcing and subsequent SST fields. © 2006 Elsevier B.V. All rights reserved. Keywords: Canonical Correlation Analysis; Empirical orthogonal function analysis; Iberian Peninsula; Wind forcing 1. Introduction The western Iberian Peninsula forms part of the northern tip of the Eastern Boundary Current System of West Europe and North Africa. At Cape Finisterre and Cape St. Vincent, the west coast runs almost at right angles to the North and South coasts respectively (Fig. 1). In addition, presence of the Gulf of Cádiz in the south and the Bay of Biscay in the north, where vivid recirculations occur (Pingree and Le Cann, 1990; Sánchez and Relvas, 2003), forms a unique meridional symmetry. The abrupt change in coastline at the capes means that, since predominant winds align either merid- ionally or zonally (Torres et al., 2003; Sánchez et al., Available online at www.sciencedirect.com Journal of Marine Systems 68 (2007) 103 – 127 www.elsevier.com/locate/jmarsys ⁎ Corresponding author. Present address: Instituto Español de Oceanografía., Promontorio de S. Martín s/n. P.O. Box 240. E- 39080, Santander, (Spain). E-mail addresses: rleal@st.ieo.es (R.F. Sánchez), prelvas@ualg.pt (P. Relvas), Marina.Delgado@irta.es (M. Delgado). 0924-7963/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jmarsys.2006.11.003