BOTTOM CURRENTS INDUCED BY BAROCLINIC FORCING IN LAKE BANYOLES (SPAIN)

Because of the difference in morphometry and in the underground heatin g of the two lobes of Lake Banyoles there is a differential cooling th at causes a density current - the denser water of the shallower lobe p lunging into the deepest lobe forming a bottom current - which redistr ibutes water between the lobes and replaces that of the northern lobe about every 5 days. This current has been studied during the mixing pe riods of the years 1989 - 1991 from temperature and current measuremen ts and it has been found that it increases or slows down depending on the direction of the wind. Furthermore, it is observed that it mainly flows along the west shore of the lake, deflecting towards the right a s an effect of the bottom morphometry. However, due to the long time s cale of the density current the influence of the earth's rotation shou ld not be neglected in advance. Finally, a simple numerical model has been used to corroborate the magnitude of this current - whose velocit y has been directly measured - which is found to be the most important in the lake during the mixing period and so, it dominates the lake-wi de circulation