Collaborative Research: Pan-Arctic climate and ecosystem response to historical and projected changes in the seasonality of sea ice melt and growth

该奖项将通过使用观测记录和地球系统模式对未来气候的预测，支持对海冰融化开始和冻结开始的季节时间变化的原因和影响进行定量评估。该研究将综合现有数据集，包括ARCSS北极系统科学综合（SASS）和北极观测网络（AON）项目的结果。这将通过社区气候系统模式第4版（CCSM4）的控制和敏感性综合分析加以补充，该模型改进了极地过程和能力，包括更一般和一致的海冰反照率表示和生态系统/生物地球化学成分。具体而言，本研究将(1)研究海冰和积雪条件的季节变化、太阳日晒量及其辐射分配之间的相互作用和反馈；(2)评估这些相互作用对冰-海-大气热量、淡水和生物可利用铁交换的影响，并研究它们对CCSM生态系统动力学、生物地球化学循环和气候的影响。(3)根据这些过程评估并最终提高地球系统模式的能力，特别是通过改进与海冰表面反照率和光透射参数化相关的物理特性。这项研究对不同的受众有许多“更广泛的影响”。研究结果将用于评估北极气候和北极生态系统在地球系统模型中的季节性循环表现，并将有助于理解北极大气-海洋-冰-海洋-生物地球化学系统中关键触发事件的复杂平衡。模型模拟结果将免费提供，对使用包括更高营养水平的生态系统模型的研究以及研究人员设计和分析观测现场项目都很有用。该研究的泛北极焦点将为在特定地理位置进行的测量和研究提供背景。通过NCAR和CRREL的指导计划，两名本科生将参与该项目。这项工作的结果将通过对当地小学的访问介绍给课堂，并纳入达特茅斯学院、加州大学欧文分校和华盛顿大学的课程。太平洋科学中心（西雅图）、伯克博物馆（西雅图）和蒙特希尔博物馆（佛蒙特州）的博物馆演示将在传统课堂之外吸引更广泛的观众。

This award will support a quantitative assessment of the causes and effects of variations in the seasonal timing of sea ice melt onset and freeze initiation, through use of the observational record and earth system model projections of future climate. The study will synthesize existing datasets including results from ARCSS Synthesis of Arctic System Science (SASS) and Arctic Observing Network (AON) projects. This will be complemented by an analysis of control and sensitivity integrations from the Community Climate System Model, version 4 (CCSM4), which has improved polar processes and capabilities, including a more general and consistent sea ice albedo representation and an ecosystem/biogeochemistry component. Specifically, the study will (1) investigate interactions and feedbacks between seasonal changes in the sea ice and snow conditions, the amount of solar insolation, and the partitioning of this radiation, (2) assess the implications of these interactions for changes in ice-ocean-atmosphere heat, freshwater, and bio-available iron exchange and investigate their influence on ecosystem dynamics, biogeochemical cycling, and climate in the CCSM, and (3) evaluate and ultimately improve the capabilities of earth system models in light of these processes, specifically by improving the physics associated with surface albedo and light transmission parameterizations for ice covered seas. This study has many 'Broader Impacts' for a variety of audiences. The results will be used to assess the representation of the seasonal cycle of Arctic climate and the Arctic ecosystem in earth system models, and will aid in understanding the intricate balance of key trigger events in the Arctic atmosphere-sea ice-ocean-biogeochemical system. The model simulation output will be freely available and useful to studies using ecosystem models that include higher trophic levels, as well as to researchers designing and analyzing observational field programs. The pan-Arctic focus of the study will provide context for measurements and studies undertaken at specific geographic locations. Through mentoring programs at NCAR and CRREL, two undergraduate students will work on the project. Results from this work will be introduced to the classroom through visits to local elementary schools, and inclusion in curricula at Dartmouth College, University of California Irvine and University of Washington. Museum presentations at the Pacific Science Center (Seattle), the Burke Museum (Seattle) and the Montshire Museum (Vermont) will reach wider audiences outside of the traditional classroom.