Key points are not available for this paper at this time.
A numerical model has been used to investigate the wind‐driven circulation in a stratified basin of moderate size, Lake Tahoe, California‐Nevada. Two types of circulation are identified: “direct” circulations, in which the current directions remain relatively constant and the mean circulation formed over several days resembles the instantaneous circulation, and “residual” circulations, in which the currents fluctuate continuously and the mean circulation is characterized by small net displacements of parcels after large oscillations. Previous studies of stratified closed basins have emphasized residual circulations caused by cyclonically propagating internal basin modes, resulting in a single cyclonic mean gyre during light to moderate winds. Observations at Lake Tahoe have shown currents which are more constant in direction, with a double gyre pattern of surface circulation, dominated by an anticyclonic northern gyre. Model experiments of Lake Tahoe demonstrate that the curl of the wind stress must be included to obtain a direct, double gyre circulation similar to the observations. Horizontally uniform winds cause a residual circulation, similar to that reported at other lakes. Use of the model to calculate the vorticity budget clarifies the role of the wind stress curl in creating the direct double gyre.
Strub et al. (Tue,) studied this question.