Collaborative Research: Characterizing the Roles of Atmospheric Structure and Clouds on the Radiation and Precipitation Budgets at Summit, Greenland

提供资金来描述格陵兰萨米特的大气状态、云特性、辐射和降水之间的相互作用。其目的是调查一些重要的云相关的过程，这些如何与北极气候系统相互作用，以及它们对地表能量和质量收支的影响。具体重点将包括：（1）低云持久性机制，它导致长期存在的北极层状云，与大气结构和表面能量收支强烈相互作用;（2）云相划分，它决定云的微物理组成，并最终决定云对大气辐射和水文循环的影响; 3）降水分配，为了了解Summit不同的降水模式以及这些模式如何影响总的表面累积。为了解决这些问题，该项目将利用部署在Summit的一套地面遥感器的详细观测结果，并结合星载主动遥感器的数据，作为NSF/AON资助的ICECAPS项目的一部分。高分辨率数值模拟也将用于研究许多细尺度云过程及其中尺度影响。对格陵兰冰盖的这些研究也将在北极其他地点进行的类似测量和模式研究的背景下进行考虑，以便了解Summit上空以及更一般意义上的整个北极的这些重要过程。大气水蒸气、云和降水极大地影响北极的表面能量和冰冻圈质量平衡，并且对这些平衡中的大部分可变性负责。据认为，最近北极海冰的快速融化可能部分是由云层和辐射的变化所驱动的。已知与云有关的过程和反馈是全球气候模型中最大的不确定性来源之一，这些缺陷在北极的模型模拟中已被清楚地确定。 因此，该项目的结果应提高我们对北极云过程的理解，并将其纳入气候模型，这反过来又将提高可预测性。由于这项研究的广泛影响，该项目将为参与大学的四名新研究生提供重要的数据分析和整合经验。此外，这项研究的数据和结果将被整合到本科课程和高中学生和教师的夏季研讨会中。

Funds are provided to characterize the interactions among the atmospheric state, cloud properties, radiation, and precipitation at Summit, Greenland. The objective is to investigate a number of important cloud-related processes, how these interact with the Arctic climate system, and their impact on the surface energy and mass budgets. Specific foci will include:1) Low-cloud persistence mechanisms that lead to long-lived Arctic stratiform clouds, which interact strongly with the atmospheric structure and surface energy budget;2) Cloud-phase partitioning, which determines the cloud microphysical composition and, ultimately, the effects that clouds have on atmospheric radiation and the hydrologic cycle; and3) Precipitation partitioning, in order to understand the different modes of precipitation at Summit and how these impact the total surface accumulation.To address these topics, this project will utilize detailed observations from a suite of ground-based remote sensors deployed at Summit as part of the NSF/AON-funded ICECAPS project in combination with data from satellite-borne active remote sensors. High-resolution numerical modeling will also be used to investigate many of the fine-scale cloud processes and their mesoscale influences. These studies over the Greenland Ice Sheet will also be considered within the context of similar measurements and model studies made at other Arctic locations in order to understand these important processes over Summit and, in a more general sense, across the Arctic.Atmospheric water vapor, clouds, and precipitation greatly affect the surface energy and cryospheric mass balances in the Arctic, and are responsible for much of the variability in these balances. It is thought that recent rapid melting of Arctic sea ice may be driven, in part, by changes in cloud cover and radiation. Cloud-related processes and feedbacks are known to be one of the greatest sources of uncertainty in global climate models, and these shortcomings have been clearly identified in model simulations over the Arctic. Thus, the results of this project should improve our understanding of Arctic cloud processes and their inclusion in climate models, which, in turn, will improve predictability. As broader impacts of this research, the project will provide important data analysis and integration experience for four new graduate students at the participating universities. In addition, data and results from this study will be integrated into undergraduate coursework and summer workshops for high school students and teachers.