Arctic Cold-Air Outbreak Mixed-Phase Cloud Characteristics, Processes and Impacts in Observations and Models

北极气候变化的速度比地球上任何地方都快。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质疑，出现了不确定性。一个主要的不确定性领域是在冷空气爆发期间形成的云层的特性，在冷空气爆发期间，北极冰层上的非常冷的气团在相对温暖的开阔海洋上向南移动。该奖项将有助于提供这些云(和降水)的观测数据，以及将于2024年春季在斯堪的纳维亚半岛北部进行的次北极地区冷空气爆发实验期间海洋和大气之间的能量交换。凯撒期间收集的观测结果将用于更好地了解冷空气爆发系统和更广泛的北极气候系统的特征，以便为气候模型和预测提供信息。该项目还将有助于改进对天气灾害的预报，对海军行动、商业航运和沿海社区具有重要意义。更广泛的领域努力包括为学生和职业早期科学家提供重要机会、国际合作和公共宣传。该奖项将有助于凯撒活动的主要更广泛的影响目标。该项目将利用对混合相云的遥感观测来表征作为云演变函数的液体和冰之间的分配，并另外使用凯撒约束的大型涡旋模拟来了解决定这种分配的过程。该奖项对凯撒活动的主要补充是利用G波段蒸气辐射计测量云中液态水的路径。研究人员假设，在海冰边缘附近产生的冷空气爆发云是完全液态的，并通过与云形态中反映的大尺度环境参数(气溶胶和动力)的相互作用，过渡到更下游覆盖着冰降水的液态云。一种相反的假设是，大部分降水也可能以过冷的细雨形式出现，这可能是由于缺乏冰核粒子(INP)。该项目的主要资金来自物理和动态气象学计划，部分资金来自北极自然科学计划。为凯撒部署观测资源由大气研究和教育设施项目提供资金。这一奖励反映了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，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 contribute to the main broader impact goals of the CAESAR campaign.This project will make use of remote sensing observations of mixed-phase clouds to characterize their partitioning between liquid and ice as a function of the cloud evolution, with an additional step of using CAESAR-constrained large-eddy-scale simulations to understand the processes that determine this partitioning. The primary addition to the CAESAR campaign from this award is the measurement of cloud liquid water path from a G-band Vapor Radiometer. The researchers hypothesize that the cold air outbreak clouds produced near the sea ice edge are fully liquid, and transition to liquid cloud overlying ice precipitation further downstream, through interactions with the large-scale environmental parameters (aerosol and dynamical) that are reflected in the cloud morphology. A counter-hypothesis is that much of the precipitation can also occur as super-cooled drizzle, potentially due to a lack of ice nucleating particles (INPs).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.