Sprungschichtneigung im Zürichsee durch Sturm

During the thermocline tilt, observed in November 1947 in Lake Zürich, a difference in level of 16 m was found between the highest point (Quaibrücke) and the equivalent lowest point (middle of the Lake Stäfa-Ufenau). The “fulcrum” line of this tilt was found somewhat N. of the deepest point and probably ran somewhat diagonally across the lake (e. g. Herrliberg-Rüschlikon) as a result of the angle between the W. wind and the longitudinal axis of the lake. Westerly storms, lasting for four days, transported enormous masses of warm, oxygen- and plankton-rich surface water up the lake; while hypolimnion water streamed down the lake in depths of 20 to 60 m. Attention is drawn to the physical and biological effects and to the frequency of these wind-induced drifts, which certainly should receive more attention in Swiss lakes.