Up- and downdrafts and Drop and Ice Nucleation Experiment (UDINE): Lidar observations and modeling of tropical and mid-latitude altocumulus

基于两台先进的气溶胶云激光雷达和一台多普勒风激光雷达的野外观测和大气模拟，将对热带和中纬度高积云的非均匀结冰进行研究。重点是高积云层中垂直运动（上升气流、下降气流、波浪）的特征，以及上升和下降气流对层状中层对流层云中液态水滴和冰晶形成的影响。调查包括：(a)中纬度EARLINET站Leipzig （UDINE 2010-2011）云演变的长期激光雷达观测，(b) 2008年冬季和夏季在佛得角测量的SAMUM-2高积云数据集（约400层）的分析，(c)观测到的高积云垂直速度场的综合统计分析，并对比热带和中纬度云层的结果，以及(d)激光雷达观测到的高积云演变（案例研究）的模拟。这种方法是独特的，对提高对大气云中冰和降水形成的理解作出了重要贡献。

Based on field observations with two advanced aerosol–cloud lidars and a wind Doppler lidar and atmospheric modeling, heterogeneous ice formation in tropical and mid–latitude altocumulus will be studied. The focus is on the characterization of vertical movements (updrafts, downdrafts, waves) in altocumulus layers and the influence of up–and downdrafts on the formation of liquid water drops and ice crystals in stratiform, mid–level tropospheric clouds. The investigations comprise: (a) Long term lidar observations of cloud evolutions at the mid–latitude EARLINET station Leipzig (UDINE 2010–2011), (b) analysis of the SAMUM–2 altocumulus data set (about 400 layers) measured at Cape Verde in the winter and summer of 2008, (c) comprehensive statistical analysis of the observed altocumulus vertical velocity fields and contrasting the findings for tropical and mid–latitude cloud layers, and (d) simulation of altocumulus evolutions (case studies) as observed with lidar. Such an approach is unique and is an important contribution to an improved understanding of the formation of ice and precipitation in atmospheric clouds.