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

热带地区深厚的、带着雨水的对流云团经常被发现聚集成簇，上面有多个积云塔，顶部是展开的铁砧。这些星团有不同的形状和大小，包括狂风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，它也可能在地球能量平衡、热带大气中水分的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，对流组织在多大程度上是自发发生的，是由云本身驱动的，还是受到风和海表面温度(SST)对比等大尺度环境因素的强迫。在理想化的模拟中已经发现了自发组织，这对热带气候和能量学有很大的影响，但在其他静止和均匀的环境中，自发组织发生得很慢。这些模拟是令人信服的，但它们与现实世界热带地区的相关性尚未完全确立，因为在热带地区，条件永远不会静止或一致。在该奖项下开展的工作旨在了解自组织在热带大西洋上空观测到的真实世界对流云团发展中的作用。该奖项还支持一项名为Piccolo的实地活动，该活动代表大西洋上空云层和对流组织的过程调查。Piccolo的主要活动是在德国研究船Meteor上部署SEA-POL，这是一种稳定的C波段极化天气雷达。这项活动是名为ORCESTRA的联合国际努力的一部分，ORCESTRA在热带大西洋组织了对流实验，从2024年8月开始，流星将在六周内从佛得角航行到巴巴多斯。这艘船将在北纬7度横渡大西洋，热带辐合区(ITCZ)的几个南北横断面将中断。热带辐合区是一条有组织的对流带，通常在赤道以北的热带海洋上空发现。SEA-POL雷达观测将与流星号上的各种其他观测系统的数据相结合，包括天气气球、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。鉴于对流组织在极端降水和飓风形成中的作用，以及有组织的对流贡献了热带地区近一半的总降雨量，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令人感兴趣，因为最近的研究表明，地球温度的上升可能会影响对流组织的程度，而对流组织又可能会影响温室气体水平增加所产生的升温程度。除了这一社会意义之外，这项工作还通过支持和培训7名研究生和2名博士后研究员产生了更广泛的影响。该活动还参与了SEA-POL PLUS计划，该计划促进了来自代表性不足群体的学生的参与，并与国际ORCESTRA工作中的合作伙伴合作，在巴巴多斯和佛得角开展了当地社区的外联活动。该奖项反映了NSF的法定使命，并通过使用基金会的智力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.