Diagnoses of Ice Initiation in Clouds from Airborne In Situ, Radar and Lidar Observations

几十年来，人们已经充分认识到大气中冰相的重要性--对于全球水循环、化学过程和能量交换。 了解冰形成过程的研究一直很激烈，但问题的复杂性使得进展缓慢。困难来自于冰粒子成核存在的许多途径，以及这些过程所嵌入的复杂的动态情况。 在观测方面以及数值模式的有关组成部分的理论基础方面都存在重大缺陷。 对流层云中形成冰粒的条件多种多样，这就要求在各种条件下收集观测数据，并对这些观测数据进行分析，以分离出不同条件下冰粒形成的最可能机制。本项目的目标是应用观测方法来描绘和量化云中的冰形成过程，并通过模型计算支持观测分析。 将利用现场仪器和安装在怀俄明州King Air和NSF/NCAR C-130研究飞机上的怀俄明州云雷达进行观测，在过去十年中进行了一系列实地项目，其中包括冰相云和混合相云的观测。 在2007年ICE-L实地活动中也将获得新的观测结果。 这些观测数据将来自新开发的怀俄明州云激光雷达。 这种对过去飞机观测结果的新分析，沿着对ICE-L新观测结果的分析，将提供许多有关冰形成的新信息。 飞机上的遥感仪器（雷达和激光雷达）以非常有效的方式补充了现场传感器的数据，不仅在确定水凝物浓度和大小的空间分布方面，而且在确定现场测量的动态背景方面。 研究中包括的云类型有波浪云、山顶云和层状云。 与冰的形成问题有关的特征已经在每一种云类型中确定，并提供了工作的起点。 此外，还将重点关注层状云类型中高度局部化的冰源的存在，这些冰源表现出空间上的不连续性，但时间上的连续性。该研究将产生更广泛的影响，在资深研究人员的指导下，提高参与研究的年轻科学家和学生对冰引发相关工作的参与。 怀俄明州空中国王和怀俄明州云雷达的持续发展将产生重大影响，这两个雷达都可以通过NSF大气科学低层大气观测设施提供给更广泛的NSF研究界。

The importance of the ice phase in the atmosphere - for the global water cycle, for chemical processes, for energy exchanges - has been well recognized for many decades. Research to understand the processes involved in how ice forms has been intense, yet the complexity of the problem makes progress slow. Difficulties arise from the many pathways that exist for the nucleation of ice particles, and from the complicated dynamic situations in which those processes are embedded. There are important shortcomings in observations, and also in the theoretical underpinnings of the relevant components of numerical models. The great variety of conditions in which ice particles are formed in tropospheric clouds dictates that observations be collected in a wide range of conditions and that those observations be analyzed to isolate the most likely mechanisms for ice particle formation in the different situations.The goal of this project is to apply an observational approach to delineating and quantifying ice initiation processes in clouds, and to support analysis of observation with model calculations. Use will be made of observations made with in situ instrumentation, and the Wyoming Cloud Radar, which were mounted on the Wyoming King Air and the NSF/NCAR C-130 research aircraft for a series of field projects over the past decade that, among other activities, included observations in ice-phase and mixed-phase clouds. New observations also will be obtained in the ICE-L field campaign of 2007. Included in these observations will be data from the newly-developed Wyoming Cloud Lidar. This new analysis of past aircraft observations, along with analysis of new observations from ICE-L, will provide much new information on ice initiation. The remote sensing instruments (radar and lidar) on board the aircraft complement the data from the in situ sensors in a very effective way, both with respect to defining the spatial distribution of the concentrations and sizes of hydrometeors, but also for the definition of the dynamic context of the in situ measurements. The cloud types included in the study are wave clouds, mountain cap clouds, and stratiform clouds. Features relevant to the question of ice initiation have been already identified in each of these cloud types and provide the starting points for the work. In addition, there will be a focus on the presence, in the stratiform cloud types, of highly localized sources of ice which exhibit spatial intermittency but temporal continuity.The research will have the broader impacts of enhancing the involvement in research of participating young scientists and students in work related to ice initiation, under the guidance of a veteran researcher. There will be significant impacts in the continued development of the Wyoming King Air and the Wyoming Cloud Radar, both of which are available to the wider NSF research community via the NSF Atmospheric Sciences Lower Atmospheric Observing Facility.