The importance of ice nucleating particle types and modes for the initiation of the ice phase and precipitation: Model simulations based on laboratory measurements.

在这个项目中，将使用COSMO-SPECS进行模型模拟，这是一个三维云模型，包括一个用于气溶胶粒子和水凝物的光谱箱微物理方案。由于微观物理学包与INUIT-1期间使用的气包模型中所含的相同，因此INUIT-1的所有新发展和修改都将转入COSMO-SPECS。首先，将模拟一个人工测试案例，即平坦地形上的一个热泡，敏感性研究将显示在冰成核颗粒类型和分布的实际变化下冰相和降水的发展。敏感性研究的另一个重点将在于所谓的小触发器的影响，即冰成核颗粒类型（例如，生物粒子）或冻结模式（如接触冻结），这些模式在第一眼上没有显示出显著的效果，但可能以最终增强冰形成的方式影响云的动力学。最后，将与RP 5合作，进行基于INUIT现场实验的真实的案例研究。不同的冰形成模式的贡献将被量化，因此，大气 INUIT实验室和现场项目中研究的冰成核制度的相关性将被估计。与此同时，INUIT-2期间研究的新粒子类型的参数化将被开发并纳入微物理方案。现有的参数化将不断修改和改进。作为该项目的一部分，将进行一些实验室实验，通过美因茨垂直风洞和声学水滴悬浮器研究接触和浸没冻结。本文重点介绍了接触冷冻实验的改进。它们将在美因茨垂直风洞中进行，过冷液滴自由漂浮在气流中，气流携带着潜在的接触冰成核颗粒沿着。因此，可以计算液滴和颗粒之间的碰撞次数，并且可以确定冻结效率，即，一次液滴-颗粒碰撞的冻结概率。

In this project model simulations will be performed with COSMO-SPECS, a 3D cloud model which includes a spectral bin microphysical scheme for aerosol particles and hydrometeors. As the microphysics package is the same contained in the air parcel model used during INUIT-1, all new developments and modifications from INUIT-1 will be transferred into COSMO-SPECS. First an artificial test case, i.e. a heat bubble over a flat terrain, will be simulated and sensitivity studies will show the development of the ice phase and precipitation under realistic variations of ice nucleating particle types and distributions. Another focus of the sensitivity studies will lie on the effects of so-called small triggers, i.e. ice nucleating particle types (e.g., biological particles) or freezing modes (such as contact freezing) which do not show significant effects on the first sight but might influence the dynamics of the cloud in the way that in the end ice formation is enhanced. Finally a real case study based on INUIT field experiments will be performed in joint cooperation with RP5. The contributions of the different ice forming modes will be quantified and, thus, the atmospheric relevance of the ice nucleation regimes which are investigated in INUIT laboratory and field projects will be estimated. Simultaneously, parameterizations of new particle types studied during INUIT-2 will be developed and included into the microphysical scheme. Existing parameterizations will continuously be modified and improved. As part of the project a number of laboratory experiments will be performed to investigate contact and immersion freezing by means of the Mainz vertical wind tunnel and an acoustic drop levitator. Here the focus lies on the improvement of contact freezing experiments. They will be conducted at the Mainz vertical wind tunnel with supercooled drops freely floated in an air stream which carries the potential contact ice nucleating particles along with. Thus, the number of collisions between drops and particles can be calculated and the freezing efficiency, i.e. the freezing probability for one drop-particle collision can be determined.