Seasonal variability of the upper warmwatersphere in the Canary Basin

Abstract

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