干旱区生态环境知识资源中心

We applied a parameterization for the emission of mineral dust particles which takes into account the relevant processes such as saltation and combines previous, physically based parameterizations. The size distribution of the soil particles is taken into account to describe the saltation. The emitted particles are described by three log-normal distributions with fixed standard deviations. A comparison of the results of a stand alone version of our parameterization with observations shows that despite tuning of model parameters there are still differences. Finally, we included the parameterization within our three-dimensional mesoscale model system for the area of the Dead Sea. The channelling effect of the Jordan Valley and stable stratification during the day modifies the horizontal distribution of the dust particles. At greater distances the size and the mass distributions of the particles is shifted towards smaller diameters due to sedimentation which is important for radiative feedback mechanisms. Sensitivity runs show the advantage of the parameterization which allows a time dependent ratio of the saltation and the emission flux at each grid point.