Dust-related ice formation in the troposphere (DRIFT)

该项目涉及利用独特的温度/湿度/气溶胶拉曼激光雷达对自由对流层云中的异质冰形成进行长期观测。这种在自然云环境中的长期观测（与山顶环境相反）是完全缺失的，但强烈需要显着提高我们对对流层气溶胶和云的相互作用的理解，并指导云模型的发展。重点是受撒哈拉沙尘影响的高积云/层云（3-9公里高度范围）中的冰形成。然而，也将研究其他气溶胶（老化的城市烟雾和森林火灾烟雾）、卷云（冰晶virga）和重力波（水滴蒸发）对高积云/层云结冰的影响。成套工作包括在撒哈拉沙尘暴爆发期间和在无尘条件下（背景或参考案例）进行两年多的激光雷达观测、激光雷达数据分析、讨论案例研究和主要调查结果，以及在德国激光雷达网（1997-2000年）和EARLINET（2000-2003年）的框架内对莱比锡拉曼激光雷达取样的云观测进行重新分析。

The project deals with long-term observations of heterogeneous ice formation in freetropospheric clouds with a unique temperature/humidity/aerosol Raman lidar. Such long-term observations in natural cloud environments (in contrast to hill top environments) are completely missing, but are strongly needed to significantly improve our understanding of the interaction of aerosols and clouds in the troposphere and to guide cloud model developments. The focus is on ice formation in altocumulus/stratus (3-9 km height range) affected by Saharan dust. However, the influence of other aerosols (aged urban haze and forest fire smoke), of cirrus (ice crystal virga) and gravity waves (evaporation of drops) on ice formation in altocumulus/stratus will be investigated as well. Work packages include lidar observations over two years during Saharan dust outbreaks and during dust-free conditions (background or reference cases), lidar data analysis, discussion of case studies and of the main findings, as well as the re-analysis of cloud observations sampled with the Raman lidar at Leipzig in the framework of the German lidar network (1997-2000) and EARLINET (2000-2003).