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

云在北极地表能量平衡中起着重要作用，控制着海冰的生长和融化。与此同时，北冰洋上空云层的形成、维持和消散过程被认为受到海冰本身的强烈影响。拟议的项目将通过问：北极云对海冰减少有什么反应来促进对这种相互作用和反馈的理解？在回答这个问题时，PI将考虑(I)引起和调节这种反应的物理过程，(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)从太空观测云对海冰变化的反应的局限性。该方法将用不同配置的区域大气模式--天气研究和预报(WRF)模式--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，并将在大尺度动力学的背景下审查与海冰有关的云层变化。将进行模型实验，以更好地了解云对海冰减少的反应所涉及的物理过程。将研究海冰驱动的云量变化和大气温湿度变化对地面和大气顶部能量平衡的影响。将评估WRF模式和典型的全球气候模式(例如，CAM)之间的海冰-云相互作用的差异。最后，将评估典型的可见光和红外线算法中使用的卫星云检测标准，以确定其在地表性质发生重大变化的情况下适当检测云变化的能力，方法是执行辐射传输计算，根据不同地表条件下的模拟大气和云响应模拟卫星的光谱信号。这项研究将解决理解变化的重大问题。北极环境变化研究的一个方面(搜索)。特别是问题/活动“海洋、冰、陆地和大气之间与北极变化有关的关键相互作用是什么？”，“反馈的方向和相对重要性是什么？”将从这一分析中受益。

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.