Combined Active Remote Sensing and Modeling of Ice Nucleating Particles and Ice Crystal Flux (COARSEMIX)

云在全球范围内发生，总是覆盖地球表面的30%以上。因此，它们通过永久地改变地球的辐射，对大气的辐射平衡产生强烈的影响。驱动云演化的过程知之甚少，特别是冰相变通过非均质冻结，因此，它们在大气环流模式中的简化表示，目前激发了许多研究活动。自由对流层气溶胶以何种速率被输送到混合相云层中，并为其补充云凝结核和冰成核粒子（INP），这是一个基本问题。虽然上升云层对于气溶胶-云-动力学相关研究是理想的，但在模拟和观测的基础上，对上升云层（高积云、高层云）的这一过程缺乏详细的描述。我们提出了一项研究，将调查气溶胶夹带和形成的冰粒在这样的云层，基于主动遥感观测（激光雷达/雷达）和详细的数值云模型。将通过最先进的数值云分辨模型研究升高云层内的气溶胶输送。为了同时关闭INP进入云层的通量和冰晶的通量，模型必须能够明确地模拟气溶胶输送和随后的云层中的冰形成。近年来，TROPOS已经开发了这种数值云模式。本文提出的COARSEMIX（冰核粒子和冰晶通量的联合主动遥感和建模）项目将是第一个联合遥感/建模的INP和冰晶数浓度封闭实验。它将提供有关气溶胶、动力学、冰的形成、云的形成和降水之间相互作用的信息。由于建模和观测组成部分之间的密切互动，该项目将使新的气溶胶/冰参数化能够直接应用于模型。

Clouds occur globally and always cover more than 30% of the Earth's surface. They have, thus, a strong influence on the radiative balance of the atmosphere by permanently changing Earth's albedo. The processes driving cloud evolution are poorly understood, especially ice phase transitions via heterogeneous freezing, and thus their simplified representation in atmospheric circulation models presently motivates numerous research activities. It is a fundamental question, at what rate free-tropospheric aerosol is transported into a mixed phase cloud layer, resupplying it with cloud condensation nuclei and ice nucleating particles (INP). A detailed description of this process for elevated cloud layers (altocumulus, altostratus) on the basis of modeling and observation is absent, although elevated cloud layers are ideal for aerosol-cloud-dynamics related studies. We propose a study that will investigate aerosol entrainment and the formation of ice particles within such cloud layers, based on active remote-sensing observations (lidar/radar) and detailed numerical cloud modeling. The aerosol transport within elevated cloud layers will be studied by means of state-of-the-art numerical cloud-resolving modeling. For a simultaneous closure between the flux of INP into a cloud layer and the flux of ice crystals out of it, the models have to be capable of explicitly simulating aerosol transport and subsequent ice formation in cloud layers. Within the recent years, such numerical cloud models have been developed at TROPOS. The here proposed COARSEMIX (Combined Active Remote SEnsing and Modeling of Ice-nucleating particles and ice crystal fluX) project will be the first combined remote-sensing/modeling closure experiment for the number concentrations of INP and ice crystals. It will deliver information about the interaction between aerosols, dynamics, ice formation, cloud formation and precipitation. The project will enable direct implementation of new aerosol/ice parameterization into models, due to the close interaction between the modeling and the observational components.