Mineral aerosols are one of the most important ice nucleating particles (INPs) because their efficiency in nucleating ice, wide transport and largest mass contribution to particulate matter in the atmosphere. They are sourced from the arid regions of the world. In this context, this work evaluates the INP potential of fourteen topsoil samples collected from subtropical South American deserts, the major source of mineral aerosols in South America, in the immersion freezing mode. Samples were obtained from three distinct regions located in the South American Arid Diagonal and recognized as potential dust source areas: the Puna-Altiplano Plateau in the north, the central-west of Argentina, and Patagonia in the south. In general, results reveal that samples from the Puna-Altiplano and Patagonia regions, and the central-west of Argentina region exhibit the highest and lowest INP abilities, respectively. The active sites per unit surface area for a given temperature were calculated and compared with previously reported values. The results demonstrate that soil mineral particles from the region of study exhibit ice nucleating abilities comparable to the inorganic fraction of agricultural soils of central Argentina. No direct relationship was identified between INP ability and the major minerals observed in the samples. This study is the first to analyze the ice nucleation properties of soil samples collected along the South American Arid Diagonal and one of the few in South America. Since the analyzed topsoil particles were collected from potential dust source regions, this work contributes to understanding the role of aerosols in initiating atmospheric ice formation, providing valuable data for empirical parameterizations. This could contribute to the improvement in the performance of climate models, as the obtained results suggest that the underestimation of coarse and super-coarse aerosols at altitudes relevant for cloud formation may lead to underestimations in INP concentrations, particularly in regions near to the emission sources.

中文翻译：

---

南美洲亚热带沙漠矿物颗粒的冰成核能力


矿物气溶胶是最重要的冰成核颗粒 （INPs） 之一，因为它们在成核冰中的效率高、传输范围广，并且对大气中颗粒物的质量贡献最大。它们来自世界上的干旱地区。在此背景下，这项工作评估了在浸入式冷冻模式下从南美洲亚热带沙漠（南美洲矿物气溶胶的主要来源）收集的 14 个表层土壤样品的 INP 潜力。样本来自位于南美干旱对角线的三个不同地区，并被公认为潜在的尘埃源区域：北部的普纳-阿尔蒂普拉诺高原高原、阿根廷中西部和南部的巴塔哥尼亚。一般来说，结果表明，来自 Puna-Altiplano 和 Patagonia 地区以及阿根廷中西部地区的样本分别表现出最高和最低的 INP 能力。计算给定温度下每单位表面积的活性位点，并与先前报告的值进行比较。结果表明，来自研究地区的土壤矿物颗粒表现出与阿根廷中部农业土壤的无机部分相当的冰成核能力。未发现 INP 能力与样品中观察到的主要矿物之间存在直接关系。这项研究首次分析了沿南美干旱对角线采集的土壤样本的冰成核特性，也是南美洲为数不多的研究之一。由于分析的表土颗粒是从潜在的尘埃源区域收集的，因此这项工作有助于理解气溶胶在启动大气冰形成中的作用，为经验参数化提供有价值的数据。 这可能有助于气候模型性能的改进，因为获得的结果表明，在与云形成相关的高度低估粗气溶胶和超粗气溶胶可能会导致低估 INP 浓度，尤其是在靠近排放源的地区。