GEOSTROPHIC SURFACE CURRENTS AS DERIVED FROM SATELLITE SST IMAGES ANDMEASURED BY A LAND-BASED HF RADAR

Sea-surface temperatures (SST), as observed from a space-borne radiome ter (AVHRR), are related to surface currents as measured by the high-f requency coastal radar (CODAR) in Norwegian coastal waters. Both syste ms yield about the same spatial resolution of the order of 1km. Introd ucing a number of simplifying assumptions, the geostrophic portion of surface currents is derived from the SST distribution and compared wit h the CODAR measurements. In areas, characterised by strong temperatur e gradients, good agreement is found for current velocity and also for relative vorticity.