A multi-faceted evaluation of aerosol impacts on Arctic clouds

该项目将利用几个北极测量点的结果，包括在阿拉斯加巴罗的长期观测和格陵兰顶峰的短期观测，以及北冰洋上的两次测量活动，以改进先前对北极气溶胶-云相互作用的估计。要做到这一点，关键的第一步将涉及了解在何种条件下地表气溶胶条件可与云层条件相媲美，这些条件通常用于编制处理这一问题的统计数据集。利用各种技术，区分表面耦合云态和解耦云态，将使对气溶胶-云相互作用的评估集中于适当的情况，从而减少统计污染。在这些情况下，将进行统计评估，以揭示关键云(例如液态水路径、冰水路径)和气溶胶(例如浓度、大小、吸湿性)之间的共同变化。结合地面辐射测量和理想化的辐射传输模拟，这项评估的结果将改进对气溶胶对北极云的净辐射影响的估计。此外，它还将提供这些关系的季节性演变和表面态依赖的概述。外展计划包括对北极地区的几次访问，重点是阿拉斯加和格陵兰的北坡。这些访问的主要目的是向由当地人(包括代表性不足的土著人民)、小学生和地方官员组成的研讨会受众传播与拟议研究有关的信息。这些访问的第二个目的是让从未有机会亲自访问北极的北极研究人员(特别是职业生涯早期的研究人员)有机会亲眼目睹他们所关注的地区。该项目还将支持科罗拉多大学的两名早期职业科学家。

The project will utilize results from several Arctic measurement sites, including long-term observations at Barrow, Alaska, and shorter-term observations from Summit, Greenland, and two measurement campaigns over the Arctic Ocean to improve upon previous estimates of Arctic aerosol-cloud interactions. To do this a critical first step will involve understanding the conditions under which surface aerosol conditions, as generally used in the compilation of statistical datasets addressing this issue, are comparable to those at cloud level. Using a variety of techniques, the distinction between surface-coupled and decoupled cloud states will focus evaluation of aerosol-cloud interactions on appropriate cases, reducing statistical contamination. From these cases, a statistical evaluation will be performed to reveal co-variation between key cloud (e.g. liquid water path, ice water path) and aerosol (e.g. concentration, size, hygroscopicity) properties. Combined with surface radiation measurements and idealized radiative transfer simulations, the results from this evaluation will provide an improved estimate of the net radiative impact of aerosols on Arctic clouds. Additionally, it will provide an overview of the seasonal evolution and surface-state dependence of these relationships. Outreach plans include several visits to Arctic regions, with a focus on the North Slope of Alaska and Greenland. The primary aim of these visits is to disseminate information relevant to the proposed research to seminar audiences consisting of local people (including underrepresented native people), primary school students, and local officials. A secondary aim of these visits is to give Arctic researchers (particularly early career researchers) who have never had a chance to visit the Arctic themselves an opportunity to see firsthand the region on which their efforts focus. This project will also support two early career scientists at the University of Colorado.