Physico-chemical parameters of mixed mineral, biomass burning and marine aerosols

在大沙漠上，矿物（和其他成分）粉尘是由自然过程和人为活动产生的。一旦进入大气层，灰尘与其他自然成分混合，如生物物质，蒸发的云滴，以及人为成分，如硫酸盐和烟灰。这些空气中的尘埃被长距离地传播。沙漠气溶胶与大气过程的相互作用在很大程度上取决于各种物理化学参数，这些参数是颗粒大小的函数，也取决于其在大气中停留时间的空间分布和变化。这些沙漠气溶胶的光学尘埃参数、大小和空间分布决定了大气中太阳辐射和红外辐射通过散射和吸收的直接相互作用。粉尘物质的体积和表面化学性质决定了其被纳入降水形成过程的可能性，这是造成额外间接影响的原因。由于这种沙漠的面积很大（占大陆面积的30%），因此观察到了世界范围的影响。该项目的重点是测量沙漠气溶胶颗粒的物理化学性质。调查包括两个主要部分。(1)：对沙漠土壤样品的大小分辨成分进行实验室检查，以便利用“美因茨沙洲”样品确定矿物和非矿物成分的光学参数，（2）：在摩洛哥进行的联合实地活动（封闭试验）期间对沙漠上空空气尘埃的大小、空间分布和成分进行实际测量。该项目提供的一套改进的数据将成为更加真实地模拟尘埃迁移及其对辐射场影响的模型的基础。

Over large deserts, mineral (and other components) dust is produced by natural processes and man-made activity. Once injected into the atmosphere, dust is mixed with other natural components like biogenic material, evaporated cloud droplets, and anthropogenic components like sulfates and soot. This airborne dust is transported long distances. The interaction of desert aerosols with atmospheric processes strongly depends on a variety of physico-chemical parameters as a function of particle size and the spatial distribution and transformation during their atmospheric residence time. Optical dust parameters, size and spatial distribution of these desert aerosols determine the direct interaction of solar and IR-radiation in the atmosphere through scattering and absorption. Bulk and surface chemistry of the dust material determines the potential to be incorporated into the formation of precipitation, which is responsible for additional indirect effects. Because of the large extent of such deserts (30% of the continents), a worldwide influence has been observed. This project focuses on mesurements of the physico-chemical properties of desert aerosol particles. The investigations consist of two major parts. (1): Laboratory investigtions on size-resolved composition of desert soil samples in order to determine optical parameters from mineral and non-mineral components using samples of the "Mainz Sandbank", (2): Actual measurements of the size and spatial distribution and composition of airborne dust over the desert during a joint field campaign (closure experiment) in Morocco. An improved data set provides by this project will be the basis for more realistic model simulations of the transport of dust and its effect on the radiation field.