Thermal fronts generated by internal waves propagating obliquely along thecontinental slope

Rapid temperature falls occurring at semidiurnal periods are observed close to the bottom above the continental slope in the Bay of Biscay. Simultaneo us current measurements reveal that the abrupt temperature decrease O(0.5 K ) within one minute is associated with a brief downslope current, contrary to previous observations. It is suggested that the flow field associated wi th internal waves propagating obliquely downslope is responsible for advect ing denser water higher on the slope than lighter fluid, resulting in a gra vitationally unstable stratification. The collapse of this stratification i s observed as a thermal front passing the moored instruments.