Collaborative Research: AGS-FIRP Track 2--Process Investigation of Clouds and Convective Organization over the atLantic Ocean (PICCOLO)

热带地区的深层、带雨的对流云经常被发现成簇，有多个积云塔，顶部有扩散的砧。这些星团有各种各样的形状和大小，包括飑线和中尺度对流系统，就像在美国大平原上发现的那样。对流组织显然是对恶劣天气的关注，它也可能在地球的能量平衡、热带大气中的水分分布以及对流驱动全球大气环流的能力方面发挥重要作用。理解对流组织在气候系统中的作用的一个关键问题是组织自发发生的程度，由云本身驱动，或由风和海表温度（SST）对比等大尺度环境因子强迫。在理想化的模拟中发现了自发组织，对热带气候和能量学有重大影响，但在其他静态和均匀的环境中，自发组织发生缓慢。这些模拟是令人信服的，但它们与现实世界热带的相关性尚未完全确定，那里的条件永远不会静止或均匀。在该奖项下进行的工作旨在了解自组织在热带大西洋观测到的真实对流云团发展中的作用。研究了集群对周围环境的影响。具体来说，该奖项支持一项名为PICCOLO的实地活动，即大西洋云和对流组织的过程调查。PICCOLO的主要任务是在德国“流星”号科考船上部署SEA-POL，一种稳定的c波段偏振气象雷达。该活动是一项名为“有组织的热带大西洋对流实验”（ORCESTRA）的国际联合行动的一部分，“流星”号将于2024年8月从佛得角航行到巴巴多斯，为期六周。该船将在北纬7度穿越大西洋，在热带辐合带（ITCZ）上有几个南北横断面中断，这是赤道以北热带海洋上空有组织的对流带。SEA-POL雷达观测数据将与来自“流星”号上其他观测系统的数据相结合，这些系统包括气象气球、w波段云雷达、微波辐射计和两个激光雷达。ORCESTRA的工作还包括来自德国HALO和法国SAFIRE研究飞机的测量。考虑到对流组织在极端降水和飓风形成中的作用，以及有组织对流贡献了热带地区近一半的降水这一事实，这项工作具有社会和科学意义。对流组织在地球能量平衡中的作用也引起了人们的兴趣，因为最近的研究表明，地球温度的上升可能影响对流组织的程度，而对流组织的程度反过来又可能影响温室气体水平增加所产生的变暖量。除了社会意义之外，通过对七名研究生和两名博士后的支持和培训，这项工作具有更广泛的影响。该运动还参与了SEA-POL PLUS项目，该项目促进了来自代表性不足群体的学生的参与，并与国际ORCESTRA项目的合作伙伴合作，在巴巴多斯和佛得角的社区开展了地方外展活动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The deep, rain-bearing convective clouds of the tropics are often found clumped into clusters with multiple cumulus towers topped by spreading anvils. These clusters come in a variety of shapes and sizes including squall lines and mesoscale convective systems like the ones found over the US Great Plains. Convective organization is clearly a concern for severe weather and it could also play important roles in Earth's energy balance, the distribution of moisture in the tropical atmosphere, and the ability of convection to drive the global atmospheric circulation. A key issue for understanding the role of convective organization in the climate system is the extent to which organization occurs spontaneously, driven by the clouds themselves, or is forced by large-scale environmental factors such as winds and sea surface temperature (SST) contrasts. Spontaneous organization has been found in idealized simulations, with substantial impacts on tropical climate and energetics, but the organization happens slowly in an otherwise quiescent and uniform environment. These simulations are compelling but their relevance to the real-world tropics, where conditions are never quiescent or uniform, has not been fully established. Work performed under this award seeks to understand the role of self-organization in the development of real-world convective cloud clusters observed over the tropical Atlantic Ocean. The effects of the clusters on the surrounding environment is also examined.Specifically, the award supports a field campaign called PICCOLO, which stands for Process Investigation of Clouds and Convective Organization Over the atLantic Ocean. The primary activity of PICCOLO is the deployment of SEA-POL, a stabilized C-band polarimetric weather radar, on the German research vessel Meteor. The campaign is part of a joint international effort called ORCESTRA, ORganized Convection ExperimentS in the TRopical Atlantic, in which the Meteor will sail from Cape Verde to Barbados over six weeks starting in August 2024. The ship will cross the Atlantic at 7 degrees north with interruptions for several north-south transects across the Intertropical Convergence Zone (ITCZ), a band of organized convection typically found north of the equator over the tropical oceans. The SEA-POL radar observations will be combined with data from a variety of other observing systems aboard the Meteor, including weather balloons, a W-band cloud radar, a microwave radiometer, and two lidars. The ORCESTRA effort also includes measurements from the German HALO and French SAFIRE research aircraft.The work is of societal as well as scientific interest given the role of convective organization in extreme precipitation and hurricane formation, as well as the fact that organized convection contributes nearly half of the total precipitation in the tropics. The role of convective organization in Earth's energy balance is also of interest given recent studies suggesting that the rising temperature of the Earth could affect the extent of convective organization, which could in turn affect the amount of warming produced by increasing greenhouse levels. Beyond this societal relevance the work has broader impacts through the support and training of seven graduate students and two postdoctoral fellows. The campaign also participates in the SEA-POL PLUS program, which facilitates participation by students from underrepresented groups, and conducts local outreach to communities in Barbados and Cape Verde in collaboration with partners in the international ORCESTRA effort.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.