Scientific Program Overview (SPO): 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，同时海洋表面对太阳的吸收过多，这可能反过来导致气候敏感性估计的误差。该奖项资助了一项名为“南大洋云、辐射、气溶胶、运输实验研究”（SOCRATES）的实地活动的规划和组织活动。该活动本身还没有得到资助，NSF也没有承诺通过颁发这个奖项来资助它。NSF通过授予该奖项，鼓励ppi提交一套建议，要求支持各种活动，这些建议将在晚些时候进行集体审查。第二轮评审将决定该活动是否进入实地，以及该活动的哪些要素将得到NSF的支持。这次活动包括部署湾流V (GV)，这是一架由位于澳大利亚霍巴特或新西兰克赖斯特彻奇的国家大气研究中心地球观测实验室维护的研究飞机。GV将向南飞越极地锋，到达南纬55度以上的较冷水域，观测大气边界层结构和云和气溶胶的垂直分布，包括云凝结核（CCN）和冰成核粒子（INPs）。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。pi假设，在给定温度下，SLW冻结的程度更受云上升气流速度的调节，而不是由INPs的可用性调节。在确定边界层云中低重力液滴的浓度时，pi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。GV配备了雷达和激光雷达，用于表征云的特性，以及使用飞机上的进气口收集和分析气溶胶、云滴和冰粒的化学和物理特性的仪器。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。如上所述，由于SO云在确定全球气候对温室气体浓度增加的响应方面的潜在重要作用，以及用于未来气候预测的气候模式中SO云的不足，这项工作具有更广泛的影响。此外，还为该运动计划了一些教育和外联活动。研究生可以通过给pi的实地考察奖励来参与活动，研究生实地考察的其他机会也将被提出。竞选后数据分析的暑期实习也将被视为竞选审查过程的一部分。此外，计划通过定期通讯和博客，以及一个互动的“问苏格拉底”网站，向K-12学生和公众推广，通过该网站，竞选pi可以回答有关云及其在气候系统中的作用的问题。

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, accompanied by excessive solar absorbtion by the ocean surface which may in turn cause errors in estimates of climate sensitivity.This award funds planning and organizational activity for a field campaign titled Southern Ocean Clouds, Radiation, Aerosol, Transport Experimental Study (SOCRATES). The campaign itself is not yet funded, nor does NSF commit to funding it by making this award. By making the award NSF encourages the PIs to submit a set of proposals requesting support for each of the various campaign activities, which are reviewed collectively at a later date. This second round of reviews determines whether the campaign goes to the field and what elements of the campaign are supported by NSF.The campaign consists of a deployment of the Gulfstream V (GV), a research aircraft maintained by the Earth Observing Laboratory of the National Center for Atmospheric Research, based either in Hobart, Australia or Christchurch, New Zealand. The GV would fly south across the polar front, reaching the colder waters beyond 55 degrees South, to obtain observations of atmospheric boundary layer structure and vertical distributions of clouds and aerosols, including cloud condensation nuclei (CCN) and ice nucleating particles (INPs). 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 freezes at a given temperature is more strongly modulated by cloud updraft velocities than by availability of INPs. 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 SLW droplets in boundary layer clouds. The GV is equipped with radar and lidar for characterizing cloud properties as well as instruments which use inlets on the aircraft to collect and analyze the chemical and physical properties of aerosols and cloud droplets and ice particles. 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.As noted above, the work has broader impacts due to the potentially significant role of SO clouds in determining the response of global climate to increases in greenhouse concentrations, and the inadequacy of SO clouds in climate models used for future climate projections. In addition, a number of education and outreach activities are planned for the campaign. Graduate students are expected to participate in the campaign through the awards given to PIs for fieldwork, and other opportunities for graduate student fieldwork will also be proposed. Summer internships for post-campaign data analysis will also be considered as part of the review process conducted for the campaign. In addition, outreach to K-12 students and the general public is planned through regular newsletters and blogs, and an interactive "Ask SOCRATES" website through which campaign PIs answer questions on clouds and their role in the climate system.