Collaborative Research: Elucidating the Role of Natural Aerosols in Modulating Boundary Layer Clouds and Precipitation in the Southern Ocean

南大洋是了解当前和未来气候的重要区域，因为云类型的持续混合影响了地球的能量平衡。对南大洋云层的更好理解有赖于对气溶胶的更好测量，气溶胶是形成云滴和冰晶的小颗粒。该项目将在澳大利亚合作者进行的一系列考察船巡航上以及在南极洲的一个地点部署一套仪器，以测量这些气溶胶。该项目的影响将是改善对南大洋上空气溶胶-云相互作用和云-气候反馈的描述，以期改进气候预测。这项工作有一个重要的外展部分，研究人员将通过在线和面对面的活动与全球K-12课堂互动。该项目还代表着强有力的国际合作。研究小组将对自然气溶胶在调节南大洋地区云和降水特性方面的作用进行观测和模拟研究。南大洋是地球上污染最少的地方之一，与尘源的距离意味着气溶胶主要是生物来源的硫酸盐，包括海洋初级生产力的影响。在南大洋和南极洲，冰核粒子(INP)的来源和丰度仍然难以量化。该项目将利用即将在澳大利亚科考船上进行的四次航行，以及在南极洲戴维斯站的部署，将现有的基于地面的测量量增加一倍，以限制南大洋的气溶胶和云特性。研究小组将通过提供额外的无线电探空仪测量并收集气溶胶、海水、海冰、雪和土壤进行离线INP和DNA分析，为先前的观测活动做出贡献。然后，研究人员将共同开发面向过程的气溶胶和云模型诊断，以便在共同体地球系统模型(CESM)中进行参数化测试和开发。该项目将产生以下成果：1)记录来自船舶来源的原始海洋三个季节的云凝结核(CCN)和云滴数量浓度(ND)的纬度梯度，2)量化ND对气溶胶类型和过程来源的敏感性，以对观测到的ND提供重要限制，以及3)记录INP和降水发生和阶段的纬度和季节变化。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，认为值得支持。

The Southern Ocean is an important region for understanding current and future climate due to a persistent mix of cloud types that affect the Earth’s energy balance. An improved understanding of Southern Ocean clouds relies on better measurements of aerosols, which are small particles that cloud droplets and ice crystals form on. This project will deploy a suite of instrumentation on a series of research vessel cruises conducted by Australian collaborators, and at a location in Antarctica, to measure these aerosols. The impact of the project will be to improve representation of aerosol-cloud interactions and cloud-climate feedbacks over the Southern Ocean, with a view towards improved climate projections. There is a significant outreach component to the work, where the researchers will interact with K-12 classrooms globally through on-line and in person activities. The project also represents strong international collaboration.The research team will conduct an observational and modeling study of the role of natural aerosols in modulating the properties of clouds and precipitation in the Southern Ocean region. The Southern Ocean is one of the least polluted places on Earth and the distance from dust sources means that aerosols are dominated by biogenically derived sulfates, including impacts from marine primary productivity. The sources and abundances of ice-nucleating particles (INPs) remain poorly quantified over the Southern Ocean and Antarctica. This project will take advantage of four upcoming voyages on Australian research vessels, and a deployment at Davis Station, Antarctica, to double the volume of existing surface-based measurements to constrain Southern Ocean aerosol and cloud properties. The research team will contribute to the pre-existing observational campaigns by providing additional radiosonde measurements and collecting aerosol, seawater, sea ice, snow, and soil for offline INP and DNA analyses. The researchers will then co-develop process-oriented aerosol and cloud model diagnostics for parameterization testing and development in the Community Earth System Model (CESM). The project will result in the following deliverables: 1) Documentation of the latitudinal gradients in cloud condensation nuclei (CCN) and cloud droplet number concentration (Nd) over the pristine oceans during three seasons derived from ship-based sources, 2) Quantification of the susceptibility of Nd to sources of aerosol types and processes to provide important constraints on the observed Nd, and 3) Documentation of latitudinal and season variability in INPs and precipitation occurrence and phase.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.