Large eddy simulation of dust devil formation in convective boundary layers on Earth and Mars

Vertical vortices such as those observed as dust devils play an important role in climate system by injection of fine sediment aerosol into the atmospheres of Earth and, especially, Mars. This study investigates the numerical simulation of naturally formed vortices in the convective boundary layers (CBLs) of both planets based on the fundamental dynamics of planetary boundary layers (PBL) over hot surfaces. A Large Eddy Simulation (LES) model developed at NCAR has been adapted for Mars and used to simulate the CBLs of Earth and Mars. It has been further developed to track and analyze the physical characteristics of naturally formed vortices and dust devils in different environmental situations. These are compared with published observations and other studies.;This study has been initiated for the analysis of the atmospheric data reported from the meteorological package (MET) of the NASA/CSA Phoenix Mars lander which collected data in 2008 during a Martian summer at 68 degrees N. Our methodology for the detection of naturally formed vertical vortices and estimation of their physical characteristics provided us the ability to find the frequency and magnitude of these vortices and to define non-stationary dust boundary conditions on the surface. Simulations have been performed for the analysis of vortices in CBLs at the lander location. The successful simulation of dust devils such as those observed by Phoenix Lander near Ls=124, and the agreement of our results with Phoenix lidar measurements, make this study a basis for future investigations on terrestrial or Martian dust devil formation.