The Response of Arctic Clouds to Changes in Sea Ice during Autumn

秋季北极云对海冰变化的响应

• 批准号: 1021274
• 负责人: Axel Schweiger
• 金额: $ 55.13万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1021274&HistoricalAwards=false
• 关键词: Response; Arctic; Clouds; Changes; Sea

Clouds play a major role in the arctic surface energy balance controlling the growth and melt of sea ice. At the same time the processes involved in the formation, maintenance and dissipation of cloud cover over the Arctic Ocean are thought to be strongly influenced by the sea ice itself. The proposed project will advance the understanding of this interaction and feedback by asking: What is the response of Arctic clouds to diminishing sea ice? In answering this question, the PI's will consider (i) the physical processes that cause and modulate this response, (ii) the role of large-scale atmospheric dynamics, (iii) the potential effects on the heat and energy balance and in climate feedbacks, and (iv) the limitations of observing from space the response of clouds to changes in sea ice. The approach will be to conduct a series of experiments with different configurations of a regional atmospheric model, the Weather Research and Forecast (WRF) model. Focusing on the autumn season, sea ice and sea surface temperature will be altered and changes in cloud cover associated with sea ice will be examined in the context of large scale dynamics. Model experiments designed to better understand the physical processes involved in the response of clouds to diminishing sea ice will be performed. The impact on the surface and the top of the atmosphere energy balance of sea-ice driven changes on cloud cover and the atmospheric temperature and humidity will be examined. Differences in sea ice-cloud interactions between the WRF model and a typical global climate model (e.g. CAM) will be assessed. Finally, satellite cloud detection criteria used in typical visible and infrared-based algorithms will be evaluated for their ability to properly detect cloud changes in the context of significant changes in surface properties by performing radiative transfer calculations to simulate the spectral signal at the satellite from modeled atmospheric and cloud responses for different surface conditions. This research will address significant questions of the ?Understanding Change? aspect of the Study of Arctic Environmental Change (SEARCH). In particular the questions/activities "What are the critical interactions among ocean, ice, land, and atmosphere as they relate to Arctic Change?", "What is the direction and relative importance of feedbacks?" will benefit from this analysis.

云在控制海冰生长和融化的北极表面能量平衡中起着重要作用。与此同时，北冰洋云量的形成、维持和消散过程被认为受到海冰本身的强烈影响。拟议的项目将通过提出以下问题来促进对这种相互作用和反馈的理解：北极云层对海冰减少的反应是什么？在回答这个问题时，PI将考虑(i)引起和调节这种响应的物理过程，（ii）大尺度大气动力学的作用，（iii）对热量和能量平衡以及气候反馈的潜在影响，以及（iv）从空间观测云对海冰变化的响应的局限性。方法将是对一个区域大气模式，即天气研究与预报（WRF）模式的不同配置进行一系列实验。以秋季为重点，海冰和海面温度将发生变化，与海冰相关的云量变化将在大尺度动力学的背景下进行研究。将进行模式实验，以便更好地了解云对海冰减少的反应所涉及的物理过程。研究海冰驱动的变化对地表和大气顶部能量平衡的影响，以及对云量和大气温度和湿度的影响。将评估WRF模式与典型全球气候模式（如CAM）之间海冰-云相互作用的差异。最后，将对典型的可见光和红外算法中使用的卫星云检测标准进行评估，以评估它们在地表特性显著变化的背景下正确检测云变化的能力，方法是通过执行辐射传输计算来模拟不同地表条件下模拟大气和云响应的卫星光谱信号。这项研究将解决的重要问题？理解变化?北极环境变化研究方面（SEARCH）。特别是“与北极变化相关的海洋、冰、陆地和大气之间的关键相互作用是什么？”、“反馈的方向和相对重要性是什么？”这些问题/活动将受益于这一分析。