Oceano-meteorological conditions in the S.E Bay of Biscay for the period 2001-2005. A comparison with the period 1986-2005 and other reference periods.

In spite of the local character of the meteorological and oceanographic data collected along the Basque coast, they are representative of mesoscale features in the Bay of Biscay and also indicate teleconnections with global scale factors such as the NAO. On the other hand, some seasons of the first 5 year period of the 21st Century have been defined as “extreme” (the warm summer in 2003; the cold and long winter in 2005; the very dry spring and summer seasons in 2005, etc.) in the southeastern Bay of Biscay and other areas. Consequently, frequent seasonal anomalies are apparent; this means that winter-summer duality prevails over the establishment (in terms of values and mean duration) of spring and autumn, as typical transitional seasons at mid-latitudes and the intergyre region of the northeastern Atlantic Ocean. The aim of this paper is to analyse the coupling between meteorological and oceanographic data, for the period 2001-2005, in comparison with the period 1986-2005 and other reference periods, in the southeastern Bay of Biscay. This will be studied from several viewpoints: i) relationships between atmospheric temperature, SST and heat content; ii) salinity in relation to the precipitation-evaporation balance and river flow; and iii) dynamic aspects related to the wind velocity and direction, e.g. the upwelling-downwelling duality as a factor combining in situ modifications and variations related to the advective-convective transport. Other purposes are to examine trends and anomaly patterns of several periods and to make a comparative assessment (in terms of slope, absolute or accumulated anomalies) depending on the reference period as well as the start and end points of the observation period itself. In addition, practical reference periods are proposed for some oceano-meteorological variables in the southeastern Bay of Biscay.