Iceland as a model for high-latitude dust sources – a combined experimental and modeling approach for characterization of dust emission and transport processes (HiLDA)

矿物尘无疑是大气中最重要的气溶胶类型之一，对气候影响和生物圈相互作用。虽然最大的灰尘排放量与温暖的沙漠有关，但最近寒冷的沙漠成为焦点。高纬度尘埃（HLD），而不是非HLD，例如参与改变附近的冰川覆盖，增强或改变高纬度海洋生产力，运输有机污染物或通过提供冰成核颗粒来改变北极云。由于目前在北极观察到重大转变，北极的尘埃供应和分布预计将发生变化。为了推断进一步的变化，需要考虑稳健的模型。然而，没有可靠的排放和分配方案的HLD存在。在北方，冰岛是一个主要的来源-截至今天最强的单一来源-将灰尘输送到北极。假设主要出口方向为向南和向东北方向。冰岛的尘埃可以传播1,000多公里，例如到达斯瓦尔巴群岛和斯匹次卑尔根群岛，因此至少影响了北极大西洋部分的很大一部分。虽然对了解北极环境具有重要意义，但迄今为止，关于冰岛尘埃浓度及其时空模式的数据集很少。特别是，关于粉尘输出的测量数据和长期数据很少。为了克服这种缺乏数据，以提高冰岛粉尘出口的理解水平，作为HLD生成的潜在概念模型，提出了HiLDA项目。HiLDA将短期密集观测期（一个月）和长期基线监测（两年）与最先进的大气尘埃模型的详细数值模拟相结合。测量地点、时间段和间隔是根据作为模型输入以及产生关于近源和区域模式的信息的要求选择的。除了两个主要的粉尘源探测在密集的操作期间的粉尘排放过程的评估，从冰岛的粉尘出口观察到两个连续运行的沿海站在主要的流出方向。此外，对法罗群岛、安多亚、扬马延马延和斯瓦尔巴特群岛的观测涵盖了区域范围。在所有地点，尘埃微观物理和尘埃成分的观察，因此系统的依赖关系和演变过程中的运输可以推导出来。最终，模型模拟将允许在更广泛的背景下解释测量结果，最终揭示HLD在地球系统中的作用，特别是北极环境。

Mineral dust is undoubtedly with regard to climate impact and biosphere interaction one of the most important aerosol types in the atmosphere. While the largest amount of dust emission is linked to the warm deserts, recently cold deserts get into focus. High-latitude dust (HLD), other than non-HLD, is e.g. involved in changing nearby glacier albedo, enhancing or modifying high-latitude ocean productivity, transporting organic pollutants or modifying arctic clouds by providing ice-nucleating particles. As major transitions are currently observed for the Arctic, dust availability and distribution in the Arctic is expected to change. For extrapolating further changes, robust model considerations are required. Yet, no reliable emission and distribution scheme for HLD exists. In the northern hemisphere, Iceland is a major source – as of today the strongest single one - delivering dust to the Arctic. The main directions of export are assumed to be in southerly and north-easterly direction. Icelandic dust can travel distances of more than 1,000 km, e.g. to Svalbard, Spitsbergen, and therefore impacts at least a large part of the Atlantic sector of the Arctic. Although of significant importance for understanding the Arctic environment, only few data sets exist on Icelandic dust concentrations and their temporal and spatial patterns so far. In particular, measurement data on dust export and long-term data are sparse. To overcome this lack of data and in order increase the level of understanding of Icelandic dust export as potential conceptual model for HLD generation, the HiLDA project, is proposed. HiLDA combines short-term intensive observation periods (one month) and long-term baseline monitoring (two years) with detailed numerical simulations by a state-of-the art atmosphere-dust model. Measurement locations, time periods and intervals have been chosen in accordance with the requirements of serving as model input, as well as of yielding information on source-near and regional patterns. Besides two major dust sources probed during intensive operation periods for assessment of dust emission processes, dust export from Iceland is observed by two continuously-operating coastal stations in the major outflow directions. In addition, the regional scale is covered by observations on Faroe Islands, Andoya, Jan Mayen, and Svalbard. At all locations, dust microphysics and dust composition is observed, so systematic dependencies and evolution during transport can be derived. Ultimately, model simulations will allow for interpreting the measurement in a broader context eventually revealing the role of HLD in the Earth system in general and for the Arctic environment in particular.