Plate 2. Second LES experiment including salinity stratification. (a) 4 hours, and (b) 5 hours after initiation of surface cooling. Parcel instability occurs in the second of these two sequential vertical temperature sections. The first section shows significant interface deformation by mixed-layer turbulence. The second picture shows the onset of the parcel instability with an 80-m wide plume penetrating the pycnocline. Contours of relative temperature in the upper 100 m are in millidegrees, and contours of relative temperature near the interface at z=-200m are in centidegrees.