| 41 | 41 | This sequence shows the development of a large dust devil during a time period of 10 minutes. The shown region has a horizontal extent of 350 m x 300 m and is about 300 m high. The dust devil is made visible by a passive scalar which is advected by the flow. The surface flux of the passive scalar is calculated by a simple parametrization of the saltation process which depends on the friction velocity (White, 1979). Due to uncertainties in the parametrization of the surface flux, the displayed concentrations of the passive scalar are in arbitrary units. Dust concentrations in the order of magnitude of 0.1 g/m3 have been found for dust devils in field measurements (Renno et al., 2004). |
