The Combined Influence of sea ice and snow cover on Northern Hemisphere Atmospheric Climate Variability

北极的冰雪是气候系统的一个组成部分。 在过去十年中，它们经历了前所未有的变化。 关于其变异性的潜在远程和更大规模影响的初步研究往往是不确定的，甚至是相互矛盾的。 在最近的一篇评论文章中，该提案的主要研究者（PI）假设海冰和积雪可以联合收割机迫使大规模的大气变化。 该项目的重点是分析再分析数据集和目标数值模拟实验的模型输出，以了解海冰和积雪变化与大气气候变化之间的物理路径。 这种变化反过来可能影响季节性时间尺度上的中纬度天气。 了解这些过程预计将改善类似时间尺度的天气预测，从而为能源，农业和再保险行业等带来好处。 该项目将通过为研究生培训提供支持，将本科生纳入科学研究，以及开发短期气候预测课程，促进STEM人力资源开发。最后，该项目将促进与德国一个研究所的国际合作，利用全大气共同体气候模式进行规定的海冰和积雪扰动实验，将导致对海冰、积雪与大气变化的开始和维持之间的物理路径进行定量评估，特别是在冬季，这是单靠统计分析无法完成的。 使用最近才出现的高顶模式来研究海冰和积雪对半球冬季环流的影响，对这一提议来说是新颖的。 同时，PI将与使用ECHAM6进行类似实验的同事合作。 他们将进一步分析再分析大气数据，以测试从模型输出中了解到的海冰和积雪在气候变率中的综合作用的假设。 拟议的项目将分析海冰和积雪异常对大气气候变化的综合影响。 这将提高对与海冰和积雪变化相关的大气响应的理解，并导致对高纬度和低纬度气候之间的联系进行定量评估，以及改进气候预测。 拟议的研究特别侧重于海冰和积雪在高纬度大气变化的主导模式，即环形模式的启动和维持方面的综合作用。 环形模的调制被假设为高纬度气候反馈的一个关键物理机制，并且是中纬度地区（包括美国、欧洲和亚洲的工业中心）的主要变率模式。 在本项目结束时，将在一个业务季节预报模式中应用本项目中开发的概念框架。

Arctic snow and ice form an integral part of the climate system. They have undergone unprecedented changes within the past decade. Initial studies on the potential remote and larger scale influences of their variability have often been inconclusive and even contradictory. In a recent review article, the principal investigators (PIs) of this proposal hypothesized that sea ice and snow cover can combine to force large-scale atmospheric variability. This project focuses on analyzing reanalysis datasets and model output from targeted numerical modeling experiments in order to understand the physical pathways linking sea ice and snow cover variability with atmospheric climate variability. This variability may, in turn, influence mid-latitude weather on seasonal time scales. Understanding such processes is anticipated to improve weather prediction on similar time scales, with consequent benefits to the energy, farming, and reinsurance industries, amongst others. The project will contribute to STEM manpower development through providing support for the training of a graduate student, entrainment of undergraduate students into scientific research, and development of a short course of climate prediction. Finally, the project will promote international collaboration with a German research institute.Prescribed sea ice and snow cover perturbation experiments with the Whole Atmosphere Community Climate Model (WACCM) will lead to a quantitative assessment of the physical pathways between sea ice, snow cover and the initiation and maintenance of atmospheric variability, particularly in winter, that cannot be accomplished using statistical analysis alone. The use of a high-top model, which has only recently become available, to study the influence of sea ice and snow cover on the hemispheric winter circulation is novel to this proposal. In parallel, the PIs will collaborate with colleagues running similar experiments with ECHAM6. They will further analyze reanalysis atmospheric data, to test hypotheses about the combined role of sea ice and snow cover in climate variability learned from the model output. The proposed project will analyze the combined impact of sea ice and snow cover anomalies on atmospheric climate variability. This will improve understanding of the atmospheric response associated with changes in sea ice and snow cover, and lead to a quantitative assessment of the links between high-latitude and lower-latitude climates as well as enable improved climate predictions. The proposed research focuses specifically on the combined role of sea ice and snow cover in the initiation and maintenance of the dominant mode of high-latitude atmospheric variability, i.e. the annular mode. Modulation of the annular mode is hypothesized to be a key physical mechanism for climate feedback in high latitudes and is the dominant mode of variability in the mid-latitudes including the industrial centers of the United States, Europe and Asia. The conceptual framework developed in this project will be applied in an operational seasonal forecast model at the end of the project.