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

在大片沙漠上，矿物(和其他成分)粉尘是由自然过程和人为活动产生的。一旦被注入大气，尘埃就会与其他自然成分混合在一起，比如生物物质、蒸发的云滴，以及硫酸盐和烟尘等人为成分。这种悬浮在空气中的尘埃被长距离输送。沙漠气溶胶与大气过程的相互作用强烈依赖于各种物理化学参数作为颗粒大小的函数，以及它们在大气停留时间内的空间分布和变化。这些沙漠气溶胶的光学尘埃参数、大小和空间分布通过散射和吸收决定了太阳和红外辐射在大气中的直接相互作用。尘埃物质的整体和表面化学决定了参与形成降水的可能性，这是产生额外间接影响的原因。由于这种沙漠的大范围(占大陆的30%)，已经观察到了世界性的影响。该项目的重点是沙漠气溶胶颗粒的物理化学性质的测量。调查包括两个主要部分。(1)：利用“美因茨沙洲”的样本，对沙漠土壤样本的尺寸分辨成分进行实验室调查，以确定矿物和非矿物成分的光学参数；(2)：在摩洛哥的一次联合实地活动(封闭实验)期间，对沙漠上空空气扬尘的大小、空间分布和成分进行实际测量。该项目提供的改进的数据集将为更真实地模拟尘埃的传输及其对辐射场的影响奠定基础。

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.