SIZE ESTIMATES OF THE FACTORS CONTROLLING SEA-SURFACE TEMPERATURE WITH AVHRR DATA

NOAA AVHRR thermal infrared images, meteorological measurements and mo del calculations have been used to estimate the magnitude of the proce sses controlling the sea surface temperature variability in the Bay of Biscay. The estimates are based on the equation of temperature conser vation and the equation for the total derivative. The results show tha t local time change, advection, horizontal diffusion and vertical turb ulent flux vary with time and space. The sea surface temperature varia bility is mainly controlled by vertical turbulent flux and advection. For an average of five-day estimates, the order of the relative import ance of the processes is vertical turbulence (38 per cent), advection (32 per cent), local time change (22 per cent) and horizontal diffusio n (8 per cent).