Seasonal variability of the upper warmwatersphere in the Canary Basin

Two years of periodic XBT data, along seven transects covering the Canary B asin, were examined to analyse the seasonal cycle of the upper layers of th e warmwatersphere. This is characterised by seasonal storage/release of hea t in the surface mixed layer and by the winter formation of a subsurface po sitive temperature anomaly. Its maximum value takes place in early winter a nd deepens to about 150 m in late spring, disappearing afterwards. We prese nt a very simple argument, which illustrates how the evolution of the tempe rature anomaly is controlled both by the ocean-atmosphere heat exchange and by the shape of the North-Atlantic Central Water T-S relationship.