Scientific Program Overview (SPO): Southern Ocean Clouds, Radiation, Aerosol, Transport Experimental Study (SOCRATES)

南大洋（SO），意思是南半球高纬度的全球海洋，作为地球上风暴最多的地方，有着当之无愧的声誉。 SO的遥远和它的恶劣条件严重限制了对它上面发生的大气过程的观测，包括沿着南极锋行进的气旋中的云过程。 然而，这些过程由于各种原因而令人感兴趣，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云还通过将入射的阳光反射回太空，在地球的能量平衡中发挥着重要的冷却作用。 有证据表明，这种冷却有一个长期的影响，低纬度降水的分布与热带辐合带，和SO云量的变化，由于全球气候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，伴随着海洋表面过度的太阳能吸收，这反过来可能导致气候敏感性估计的错误。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。 该运动本身尚未获得资助，NSF也没有承诺通过颁发该奖项来资助它。通过授予奖项，NSF鼓励PI提交一套提案，要求对各种活动的每一项活动提供支持，这些活动将在稍后进行集体审查。 第二轮评审将决定该活动是否进入实地以及NSF支持该活动的哪些要素。该活动包括部署湾流V（GV），这是一架由国家大气研究中心地球观测实验室维护的研究飞机，该实验室位于澳大利亚的霍巴特或新西兰的基督城。 GV将向南飞行穿过极锋，到达南纬55度以上较冷的沃茨，以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）。 活动中要解决的一个关键问题是SO云中过冷液态水（SLW）液滴和冰粒的相对丰度，因为SLW在SO云中比北方云中更普遍。 PI假设SLW在给定温度下冻结的程度受云上升气流速度的调制比INPs的可用性更强。 PI还试图确定上覆的自由对流层气溶胶浓度与当地地面和边界层控制（包括降水和风速）的相对影响，以确定边界层云中SLW液滴的浓度。 GV配备了用于表征云特性的雷达和激光雷达，以及使用飞机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。 SOCRATES活动是对国际上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度无人居住的小岛MacQuarie岛上进行的地面观测。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反应方面的潜在重要作用，这项工作具有更广泛的影响。以及用于未来气候预测的气候模式中SO云的不足。 此外，还计划为该运动开展一些教育和外联活动。 预计研究生将通过授予PI实地考察的奖项参与该活动，并将提出研究生实地考察的其他机会。 还将考虑为运动后数据分析提供暑期实习机会，作为为运动开展的审查进程的一部分。 此外，还计划通过定期通讯和博客以及互动式“问苏格拉底”网站向K-12学生和公众进行宣传，通过该网站，运动PI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.