Results 5, Mushroom Structure, Top-View Animation

Figure 6 shows the animation of the vorticity surface from the top of the model domain for the other interesting structure for the experiment shown by blue triangle in Fig.2. The vortex structure shows larger anticyclonic vortexes (blue) and smaller cyclonic vortexes (red). Under the anticyclonic vortexes, the cyclonic vortexes are located, as seen in the view from the bottom (Fig. A2). The presence of the vortex pair is a common feature with the heton. However, the anticyclonic vortexes are not stable, but often break up and cannot be continuously detectable as a single vortex. This temporal variability is in contrast to the idealistic hetons, which are quasi-stable, and the hetons movements are assumed to cause the variations of total flow fields. For the ideal representations of hetons and their movements, see e.g, Legg and Marshall (1993) and references therein. Consequently, although the presence of the vortex pair for the structure shown in Fig. 6 is somewhat similar to the heton, the temporal variation of the present structure is likely to play a more important role than that of the heton in the variation of the total flow field.

Figure 6. Same as Fig. 4, but for the experiment for the blue triangle shown in Fig. 2. The maximal value of the three-dimensional vorticity with the positive vertical vorticity is 7.7*10^-4s^-1, and the maximal value with the negative vertical vorticity is 5.1*10^-4s^-1. The parameters for this experiment are heat flux of 800 Wm^-2,=4.0*10^-4s^-1, and =2.0 m²s^-1, and hence =7.9*10^-2,and =5.0*10⁴.