From lab to field: examining immersion freezing of atmospheric relevant ice nucleating particles

在这里建议的项目，在RP 6的INUIT-2，目的是增加基本的理解，非均质冰成核的运作，特别是生物和混合矿物-生物冰成核粒子（INP）在其中的作用。莱比锡气溶胶云相互作用模拟器（LACIS）将被用来研究一套不同的INP，包括生物（真菌）和混合的生物矿物INP，其中包括大气相关的材料，如土壤粉尘和INUIT-2测试样品的浸没冷冻行为。对于后者，将对来自INUIT内部和外部的不同组获得的结果进行相互比较，因为它已在INUIT-1中使用更简单的测试INP成功完成。对于RP 6中建议进行检查的INP，只要有意义且可行，将进行表面处理，例如使用反应性和非反应性物质进行涂层，并检查其对作为INP的颗粒的影响。正如LACIS早期研究所记录的那样，受控表面处理是确定颗粒成为有效INP的一种极好工具。此外，它们允许阐明老化对INP的影响。还计划将我们的测量扩展到水亚饱和条件，以检查在何种条件下观察到的异相冰成核是由于浓缩溶液或沉积冰成核的浸没冻结。从获得的实验数据，不同的参数，包括时间依赖和时间无关的，将得出和提供给社会进一步用于模拟研究。这里提出的研究将大大增加和补充INUIT-1期间在LACIS进行的非常成功的工作，该工作更侧重于纯矿物粉尘和纯生物颗粒。更复杂的，因此更大气相关的INP的检查将显着有助于理解和量化大气冰成核一般和矿物和生物物质的相对贡献，特别是大气冰成核。

The project suggested here, in RP6 of INUIT-2, aims at adding fundamental understanding to the workings of heterogeneous ice nucleation, and especially to the role of biological and mixed mineral-biological ice nucleating particles (INP) therein. The Leipzig Aerosol Cloud Interaction Simulator (LACIS) will be used to investigate the immersion freezing behaviour of a suite of different INP, including biological (fungal) and mixed biological-mineral INP, among them atmospherically relevant materials like soil dusts and INUIT-2 test samples. For the latter, results gained by different groups, from within and outside of INUIT, will be intercompared, as it had been successfully done in INUIT-1 using simpler test INP. For the INP proposed for examination in RP6 wherever meaningful and feasible, surface treatments such as coatings with reactive and nonreactive substances will be applied, and their influence of the particles to act as INP will be examined. As documented in earlier studies at LACIS, controlled surface treatments are an excellent tool for determining what it is that makes a particle an effective INP. Furthermore they allow for the elucidation of the effects of aging on INP. It is also planned to extend our measurements towards water sub-saturated conditions, in order to examine under which conditions the observed heterogeneous ice nucleation is due to the immersion freezing of concentrated solutions or deposition ice nucleation. From the experimental data gained, different parameterizations, both time dependent and time independent, will be derived and offered to the community for further use in modelling studies. The here proposed studies will significantly add to and complement the very successful works performed at LACIS during INUIT-1, which had focused more strongly on pure mineral dusts and pure biological particles. The examination of more complex and hence more atmospherically relevant INP will significantly contribute to understanding and quantifying atmospheric ice nucleation in general and the relative contributions of mineral and biological substances to atmospheric ice nucleation in particular.