Corrientes baroclínicas y secas internas en el lago de Banyoles

Abstract

Wind induced phenomena as the set-up of the therrnocline and the consequent interna1 seiches have been recorded in the southern lobe of Banyoles Lake. The observed period is in agreement with that obtained theoretically by the MortimerIDefant method. During these events -about two days- the thermocline migrated more than two meters. The Richardson number during this period «f seiches suggests that the induced shear was not the force but the direct effect of the wind. From November to April a bottom baroclinic current from north to south was also recordered. The differential heating between the two lobes is due to their significantly different depth and to the different incoming heat flux through the underground sources. This current can be observed indirectly from temperature data but also directly from the data recordered in a currentmeter too. The current is highly influenced by the wind blowing in the northsouth direction. In the central part of the lake, currents up to 12 cmls are observed. Their path, slightly inflected towards the right, seerns to be influenced by the bottom of the lake, but Coriolis force may be also important