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，被誉为地球上最暴风雨的地方是当之无愧的。SO的偏远及其不可饶恕的条件严重限制了对其上方发生的大气过程的观测，包括沿南极锋面移动的气旋中的云过程。然而，出于各种原因，这些过程是有意义的，包括这样一个事实，即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。因此，云层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，这种冷却对与热带辐合带有关的低纬降水的分布有长期影响，全球气候变化导致的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气候模式模拟中发现的SO云覆盖不足，伴随着海洋表面对太阳的过度吸收，这反过来又可能导致气候敏感性的估计错误。该奖项为题为南大洋云、辐射、气溶胶、输送实验研究(苏格拉底)的实地活动的规划和组织活动提供资金。这项活动本身还没有资金，NSF也没有承诺通过颁发这个奖项来资助它。通过颁发奖项，国家科学基金会鼓励私人投资机构提交一套提案，请求支持每一项不同的竞选活动，这些提案将在以后进行集体审查。这第二轮审查决定了这项活动是否进入实地，以及活动的哪些要素得到了NSF的支持。活动包括部署湾流V号(GV)，这是一种由设在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将飞越极锋向南飞行，到达南纬55度以上较冷的水域，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)和冰核(INP)。这项运动中需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富程度，因为SLW在SO云中比北半球的对应云更普遍。PI假设，SLW在给定温度下冻结的程度更受云层上升气流速度的影响，而不是INP的可用性。PIS还试图确定在确定边界层云中SLW液滴浓度时，上覆自由对流层气溶胶浓度与包括降水和风速在内的当地地面和边界层控制的相对影响。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。苏格拉底的活动是对国际上和美国其他机构计划的SO活动的补充，包括在船只上和在南纬54度的无人居住的小岛麦夸里岛上进行的地面观测。如上所述，这项工作具有更广泛的影响，因为SO云在确定全球气候对温室气体浓度增加的反应方面可能发挥重要作用，以及SO云在用于未来气候预测的气候模型中的不足。此外，还计划为这一运动开展一些教育和外联活动。预计研究生将通过颁发给专业人士的田野作业奖励来参与这项运动，还将提出其他研究生田野作业的机会。运动后数据分析的暑期实习也将被考虑作为运动审查进程的一部分。此外，计划通过定期通讯和博客，以及“问苏格拉底”互动网站，向K-12学生和普通公众进行宣传，竞选活动个人通过该网站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.