Cloud-Aerosol-Dynamic Interactions in Cold Air Outbreaks over the Arctic Ocean

北极气候的变化速度比地球上任何地方都要快。气候预测表明，北极将继续变暖，但由于对北极云未来行为的疑问，不确定性出现了。一个主要不确定的领域是在冷空气爆发期间形成的云的性质，在冷空气爆发期间，北极冰层上的非常冷的气团向南移动，越过相对温暖的开阔海洋。该奖项将有助于在亚北极地区冷空气爆发实验（CAESAR）期间提供这些云（和降水）的观测数据以及海洋和大气之间的能量交换，该实验将于2024年春季在斯堪的纳维亚北部进行。在凯撒期间收集的观测资料将用于更好地了解冷空气爆发系统的特征，以及更广泛地了解北极气候系统，以便为气候模型和预测提供信息。该项目还将有助于改善与海军作战、商业航运和沿海社区密切相关的天气灾害预报。更广泛的领域努力包括为学生和早期职业科学家、国际合作和公众宣传提供重要机会。该奖项将通过俄克拉荷马大学现有项目为本科生提供多种参与途径。该项目的重点是提供对冷空气爆发（CAOs）中产生和维持过冷液态水（SLW）的微物理过程的基本新认识，包括初级冰核和次级冰产生、表面通量和湍流混合的作用。研究小组将主要负责与NCAR协调CDP、2DS、2DC、HVPS3、King、RICE和Nevzorov探针的使用和加工。2DS， 2DC和HVPS3数据将使用伊利诺伊大学/俄克拉荷马光学阵列探针处理软件（UIOOPS）进行处理。可验证的假设包括：1)在给定云顶温度下，与气溶胶、云凝结核（CCN）和冰核粒子（INP）性质相比，SLW、冰质量和毛毛雨中冰的变化与上升气流速度的相关性更大；(2)层云和对流云的云性质与气溶胶和/或湍流的关系不同，在层云和对流云中，SLW对前者的作用更大，而湍流混合对后者的作用更大；(3)当对流翻转增多导致降水减少时，生成单体在决定云性质方面更为普遍/重要，初生冰的形成随着降水、离海冰的距离和CAO强度的增加而增加；(4)冰川作用主要由次生冰产生驱动；云性质与云上气溶胶和INP浓度的相关性强于云下气溶胶和INP浓度。该项目的主要资金来自物理和动态气象学项目，部分资金来自北极自然科学项目。CAESAR观测资产的部署由大气研究和教育设施项目资助。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。

Arctic climate is changing at a faster pace than anywhere on Earth. Climate projections indicate that the Arctic will continue to warm, but uncertainties arise due to questions about the future behavior of Arctic clouds. An area of primary uncertainty is the properties of clouds that form during cold-air outbreaks, where very cold airmasses over the Arctic ice move southward over the relatively warm open ocean. This award will help to provide observational data of these clouds (and precipitation) and the exchange of energy between the ocean and atmosphere during the Cold-Air outbreak Experiment in the Sub-Arctic Region (CAESAR), which will be conducted in Spring 2024 out of northern Scandinavia. The observations collected during CAESAR will be used in an effort to better understand the characteristics of the cold-air outbreak system, and the Arctic climate system more broadly, in order to inform climate models and projections. The project will also help to improve forecasting of weather hazards with significant relevance to naval operations, commercial shipping, and coastal communities. The broader field effort includes significant opportunities for students and early-career scientists, international collaboration, and public outreach. This award will feature multiple routes for participation by undergraduate students through existing programs at the University of Oklahoma. This project focuses on providing fundamental new understanding of the microphysical processes responsible for the production and maintenance of supercooled liquid water (SLW) in cold air outbreaks (CAOs), including the role of primary ice nucleation and secondary ice production, surface fluxes and turbulent mixing. The research team will have primary responsibility of coordinating with NCAR on the use and processing of the CDP, 2DS, 2DC, HVPS3, King, RICE and Nevzorov probes. The 2DS, 2DC and HVPS3 data will be processed using the University of Illinois/Oklahoma Optical Array Probe Processing Software (UIOOPS). The testable hypotheses include: 1) variations in SLW, ice mass and ice in drizzle at given cloud top temperatures are more correlated with updraft velocities than aerosol, cloud condensation nuclei (CCN), and ice nucleating particle (INP) properties; 2) relationships between cloud properties with aerosols and/or turbulence are different for stratus and convective clouds, with SLW playing a larger role in the former and turbulent mixing in the later; 3) generating cells are more prevalent/important in determining cloud properties when fetch is reduced due to more convective overturning, with primary ice initiation increasing with fetch, distance from the sea ice and CAO intensity; 4) glaciation is principally driven by secondary ice production; 5) cloud properties are more strongly correlated with aerosol and INP concentrations above cloud than below cloud.Primary funding for this project comes from the Physical and Dynamic Meteorology program with partial funding from the Arctic Natural Sciences program. The deployment of observational assets for CAESAR is being funded by the Facilities for Atmospheric Research and Education program.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.