Ice Nucleating Particle Influence on Southern Ocean Clouds: Measurements and Analyses for Southern Ocean Clouds, Radiation, Aerosol, Transport Experimental Study (SOCRATES)

南大洋（SO），意思是高纬度南半球的全球海洋，作为地球上风暴最多的地方，它有着当之无愧的声誉。SO的偏远及其恶劣的条件严重限制了对其上方发生的大气过程的观测，包括沿南极锋移动的气旋中的云过程。然而，由于各种原因，这些过程引起了人们的兴趣，其中包括SO云相对不受大陆和人为气溶胶的影响，因此该地区是研究原始条件下云行为的天然实验室。SO云还通过将射入的阳光反射回太空，在地球的能量平衡中起着重要的冷却作用。有证据表明，这种冷却对与热带辐合带相关的低纬度降雨分布具有长期影响，并且由于全球气候变化导致的SO云量变化将影响南半球急流的位置和强度。我们对SO云过程缺乏了解的一个指标是在气候模式模拟中发现的SO云覆盖不足，这伴随着海洋表面对阳光的过度吸收，这反过来可能导致对气候敏感性估计的误差。模拟云量的不足在沿SO风暴路径行进的锋面天气系统冷、干扇区的边界层和对流层下层云（顶部低于3km）中最为明显。这项由该奖项资助的工作是名为“南大洋云、辐射、气溶胶、运输实验研究”（SOCRATES）的大型野外活动的一部分。该活动的主要活动是部署一架湾流V （GV）研究飞机，由美国国家大气研究中心地球观测实验室维护。GV将以澳大利亚霍巴特为基地，进行多次飞越南极锋的飞行，收集SO云及其发生的气象条件的数据。GV配备了用于记录环境气象条件的落差探空仪，用于观测云层的雷达和激光雷达，以及安装在机翼上或位于入口后面的仪器，用于对气溶胶和云颗粒（液滴和冰晶）进行取样、收集和分析。苏格拉底活动是对国际和其他美国机构计划的SO活动的补充，包括在船上和在南纬54度的一个无人居住的小岛麦夸里岛进行的水面观测。运动中需要解决的一个关键问题是SO云中相对丰富的过冷液态水（SLW）液滴和冰粒，因为SLW在SO云中比北半球的同类云更普遍。PIs假设，在SO云中，SLW云滴冻结成冰粒的程度更强烈地受到云上升气流的活力的调节，而不是受到冰核粒子（INPs，液滴内触发冻结的粒子）的调节。在确定边界层云中液滴的浓度时，指数还试图确定上覆自由对流层气溶胶浓度与当地地表和边界层控制因素（包括降水和风速）的相对影响。这个项目的工作重点是了解SO云中冰晶的形成，这是确定与SLW液滴相比冰颗粒丰度相对较低是否是由于缺乏INPs的必要步骤。安装在机翼上的专用入口称为逆流虚拟冲击器（CVI），用于收集云液滴和冰晶，并将它们与周围的气溶胶和其他非云物质分离。使用一种被称为连续流动扩散室（CFDC）的设备进行进一步处理，将INPs从不利于冰形成的云凝结核（CCN，水蒸气在其上凝结形成液滴的粒子）中分离出来。收集INPs，然后使用包括电子和x射线显微镜在内的实验室技术对其进行分析，以确定其成分和其他特性。在同一地区作业的一艘澳大利亚科考船也收集了类似的数据。这些数据与其他活动数据相结合，以解决以下问题：* INP浓度是否可以预测云冰川的程度？*底层海洋的浪花和自由对流层的远距离输送作为SO云中INPs的来源的相对作用是什么？* INP的特征和丰度是否与表层海水组成（在科考船上测量）有关，包括有机物和生物活性？*苏格拉底观测提供了什么证据来证明二次冰形成过程的存在与否（即以各种方式由其他冰粒形成冰粒）？由于SO云在确定全球气候对来自温室气体增加和其他因素的外部强迫的敏感性方面具有潜在的重要作用，因此这项工作具有更广泛的影响。该活动的数据将用于开发用于天气预报和气候影响评估的模型中更好的云表示。这些数据将提供给全世界的科学界，因此，通过为基础科学研究创造一个社区资源，该运动具有更广泛的影响。这项工作还通过与澳大利亚同事的伙伴关系促进了国际科学合作。夏季实习计划在ppi所在的机构进行，允许本科生参与竞选后的数据分析，并通过定期的时事通讯、博客和一个互动的“问苏格拉底”网站向K-12学生和公众推广。该项目为一名博士后研究员和一名研究生提供支持和培训，从而为该研究领域的未来劳动力提供支持。

The Southern Ocean (SO), meaning the global ocean of the high latitude Southern Hemisphere, has a well-deserved reputation as the stormiest place on earth. The remoteness of the SO and its unforgiving conditions have severely limited observations of atmospheric processes occurring above it, including cloud processes in the cyclones traveling along the South Polar front. Yet these processes are of interest for a variety of reasons, including the fact that SO clouds are relatively free from the effects of continental and anthropogenic aerosols, and the region is thus a natural laboratory for the study of cloud behavior under pristine conditions. SO clouds also play a significant cooling role in the energy balance of the planet by reflecting incoming sunlight back to space. There is evidence to suggest that this cooling has a long-range effect on the distribution of the low-latitude rainfall associated with the intertropical convergence zone, and that changes in SO cloudiness due to global climate change will affect the location and strength of the Southern Hemisphere jet stream. One indicator of our lack of understanding of SO cloud processes is the inadequate SO cloud cover found in climate model simulations, which is accompanied by excessive absorption of sunlight by the ocean surface which may in turn cause errors in estimates of climate sensitivity. The deficiency in simulated cloud cover is most pronounced in boundary layer and lower-tropospheric clouds (tops below 3km) in the cold, dry sectors of frontal weather systems traveling along the SO storm track.The work funded under this award is part of a larger field campaign titled Southern Ocean Clouds, Radiation, Aerosol, Transport Experimental Study (SOCRATES). The primary activity of the campaign is the deployment of a Gulfstream V (GV) research aircraft maintained by the Earth Observing Laboratory of the National Center for Atmospheric Research. The GV will be based in Hobart, Australia and make multiple flights across the South Polar front collecting data on SO clouds and the meteorological conditions in which they occur. The GV is equipped with dropsondes to record ambient meteorological conditions, radar and lidar to observe the clouds, and instruments mounted on the wings or positioned behind inlets to to sample, collect and analyze aerosols and cloud particles (liquid droplets and ice crystals). The SOCRATES campaign is complementary to SO activities planned internationally and by other US agencies, including surface observations taken on ships and on MacQuarie Island, a small uninhabited island at 54 degrees South.A key issue to be addressed in the campaign is the relative abundance of supercooled liquid water (SLW) droplets and ice particles in SO clouds, as SLW is more prevalent in SO clouds than their Northern Hemisphere counterparts. The PIs hypothesize that the extent to which SLW cloud droplets freeze into ice particles is more strongly modulated in SO clouds by the vigor of cloud updrafts than by the availability of Ice nucleating particles (INPs, particles within liquid droplets which trigger freezing). The PIs also seek to determine the relative influence of overlying free tropospheric aerosol concentrations versus local surface and boundary layer controls, including precipitation and wind speed, in determining the concentration of liquid droplets in boundary layer clouds.Work in this project is specifically focused on understanding the formation of ice crystals in SO clouds, a necessary step in determining whether the relatively low abundance of ice particles compared to SLW droplets is due to a dearth of INPs. A specialized wing-mounted inlet called a counterflow virtual impactor (CVI) is used to collect cloud liquid droplets and ice crystals and separate them from ambient aerosols and other non-cloud material. Further processing using a device known as a continuous flow diffusion chamber (CFDC) separates INPs from cloud condensation nuclei (CCN, the particles on which water vapor condenses to form liquid droplets) which are not conducive to ice formation. INPs are collected and later analyzed using laboratory techniques including electron and X-ray microscopy to determine their composition and other properties. Similar data is collected on an Australian research vessel operating in the same region. These data are combined with additional campaign data to address questions including:* Are INP concentrations predictive of the extent of cloud glaciation?* What are the relative roles of sea spray from the underlying ocean and long-range transport in the free troposphere as sources for INPs in SO clouds?* Can INP characteristics and abundances be related to surface seawater composition (measured on the research vessel), including organic matter and biological activity?* What evidence do SOCRATES observations provide for the occurrence or absence of secondary ice formation processes (i.e. ice particles formed from other ice particles in various ways)?The work has broader impacts due to the potentially significant role of SO clouds in determining the sensitivity of global climate to external forcing from greenhouse gas increases and other factors. Data from the campaign will be used to develop better representations of clouds in models used for weather prediction and climate impacts assessments. The data will be made available to the worldwide scientific community, thus the campaign has broader impacts by creating a community resource for basic science research. The work also promotes international scientific collaboration through its partnership with Australian colleagues. Summer internships are planned at the PIs' home institution to allow undergraduate students to participate in post-campaign data analysis, as well as outreach to K-12 students and the general public through regular newsletters and blogs, and an interactive "Ask SOCRATES" website. This project provides support and training to a postdoctoral researcher and a graduate student, thereby providing for the future workforce in this research area.