Microphysics of ice particles at the polar summer mesopause (Microlce)

在温度低于~ 150k、高度在80 ~ 90km之间的极地夏季中间层顶，纳米尺度的大气烟雾粒子可能在中间层冰粒上成核。在有利的条件下，从地面上可以看到它们作为夜光云。这些冰粒改变了周围等离子体的电荷状态，因此伴随着雷达回波，被称为极地中间层夏季回波。这两种现象都可以通过地面遥感方法直接观测到，因此是对中间层顶难以捉摸的物理和动力学过程的有价值的探测。这些信号的变化经常被用来推断该高度区域的长期气候趋势。尽管这一点很重要，但我们对冰在中间层顶的热力学、化学和电环境中的成核和生长过程缺乏基本的认识。这种认识的进展将显著提高中间层模式的描述和预测能力，从而提高我们对中间层顶区域在气候系统中的作用的认识。最近，卡尔斯鲁厄理工学院（Karlsruhe Institute of Technology， KIT）建立了一个新的实验装置，对这些过程进行全面的实验室实验成为可能，该装置允许在真实的中间层条件下研究纳米颗粒上的冰核。在卡尔斯鲁厄（T. L.）的实验组和k<s:1>隆斯伯恩（M. R.）的建模团队的密切合作下，我们提议研究由橄榄石等典型矿物组成的真实纳米颗粒上冰的成核和生长速率，并将研究结果应用于中间层模型。所有的模型结果都将与<s:1>赫隆斯伯恩研究所提供的观测结果进行验证。此外，我们希望确定不断增长的矿物/冰系统的光学特性，以便与遥感信号进行直接比较。由罗斯托克大学和k<s:1>隆斯伯恩的IAP小组提出的一个平行项目（ELOMA）将补充关于大气烟雾粒子的电子和光学特性的预定研究。

Mesospheric ice particle may nucleate in the polar summer mesopause at heights between 80–90 km and temperatures below ~150 K on nanometer sized meteoric smoke particles. Under favorable conditions, they are visible from ground as noctilucent clouds. These ice particles modify the charge state of the surrounding plasma and are therefore accompanied by radar echoes, known as polar mesosphere summer echoes. Both phenomena can be observed straightforwardly by remote sensing methods from the ground and thus are valuable probes for the otherwise elusive physical and dynamical processes at the mesopause. Changes in these signals are often used to infer long term climatic trends in this height region. Despite of this importance, we are lacking fundamental knowledge about the nucleation and growth processes of ice in the thermodynamic, chemical and electrical environment of the mesopause. Progress in this understanding would significantly enhance the descriptive and predictive capabilities of mesospheric models and thus our understanding of the role of the mesopause region in the climate system. Comprehensive laboratory experiments on these processes have become possible only recently with the establishment of a new experimental setup at the Karlsruhe Institute of Technology (KIT), which allows to study ice nucleation on nanoparticles under realistic mesospheric conditions on well characterized mineral nanoparticles. In close collaboration between the experimental group in Karlsruhe (T. L.) and the modeling team in Kühlungsborn (M. R.) we propose to study the nucleation and growth rates of ice on realistic nanoparticles composed of typical minerals as olivine and to implement the findings into mesospheric modeling. All model results will be validated versus observational results available at the IAP Kühlungsborn. Furthermore we want to determine the optical properties of the growing mineral/ice systems to allow for a direct comparison with remote sensing signals. A parallel project (ELOMA) proposed by groups from the University of Rostock and the IAP in Kühlungsborn will complement the scheduled research with respect to the electronic and optical properties of the meteoric smoke particles.