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-云激光雷达和一台风多普勒激光雷达的野外观测和大气模拟，将研究热带和中纬度高积云中的非均匀冰形成。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。这些调查包括：(A)中纬度EARLINET站莱比锡云演变的激光雷达长期观测(Udine 2010-2011年)；(B)2008年冬夏在佛得角测量的Samum-2高积云数据集(约400层)的分析；(C)对观测到的高积云垂直速度场进行综合统计分析，比较热带云层和中纬度云层的研究结果；(D)模拟激光雷达观测的高积云演变(个案研究)。这种方法是独一无二的，是对更好地了解大气云中冰和降水形成的重要贡献。

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.