Measurement and Modelling of the Variability of Lake Ice Growth and Decay in Alaska

自1846年以来，北半球湖泊和河流的冰盖持续时间减少了近20天。自1969年以来，加拿大安大略省湖泊的冰期缩短了三周，造成了重大的湖泊学和生态变化。自20世纪80年代末/ 90年代初以来，北极的海洋、大气和冰冻圈发生了显著的环境变化。最近发布的2001年政府间气候变化专门委员会第三次评估表明，随着北纬地区冬季气温和降水的增加，敏感且已经在变化的北部高纬度冰冻圈将面临进一步的变化。阿拉斯加的湖冰可能对20世纪后期的环境变化作出反应，也可能对进一步的气候扰动作出反应。然而，观测记录既不够长，也不够连续，所涵盖的时间也不够长，无法对过去的湖冰变率和未来变化的可能幅度进行适当的评估。本研究的目的是利用数值模拟方法模拟阿拉斯加不同气候带湖泊冰生长和衰减在当前和气象记录期间的变率，并了解造成这种变率的因素，以便预测冰对未来气候变化的响应。湖冰的生长和衰减变量包括冻结、冰厚、增厚模式[凝结冰、雪冰]和破裂。这是一组比以前考虑过的更大、更全面的变量，它们综合了温度和降水变率的影响。这项研究的成功完成将产生经过良好验证的湖冰生长和衰减模型，使我们能够确定导致湖冰生长和衰减变异性的关键因素。这将填补在认识和理解北极和亚北极冰冻圈对过去气候变率和变化的响应以及对未来响应的预测方面的重大空白。这将有利于物理、化学和生物湖泊学家，以及生态和水资源管理者。教师和学生的参与将使他们更好地欣赏当地环境下的教学，理解科学过程，以及气候变化和变化对阿拉斯加物理过程和相互作用的影响的有趣和相关的例子。

Abstract JefferiesOPP-01-17645Since 1846, the duration of the ice cover on Northern Hemisphere lakes and rivers has decreased by almost 20 days. A three week reduction in ice duration on lakes in Ontario, Canada since 1969 has caused major limnological and ecological changes. Since the late 1980s/early 1990s, there has been significant environmental change in the ocean, atmosphere, and cryosphere of the Arctic. The recently released third assessment of the Intergovernmental Panel on Climate Change, 2001 indicates that the sensitive and already changing northern high latitude cryosphere faces further change as winter temperatures and precipitation increase at high northern latitudes. Lake ice in Alaska may be responding to late twentieth century environmental changes and may respond to further climatic perturbations. However, the observational record is neither sufficiently long and continuous, nor covers the appropriate period to allow for a proper assessment of past lake ice variability and the likely magnitude of future change. The objective of this study is to use numerical modeling to simulate the variability of lake ice growth and decay at the present time and during the period of meteorological record in the different climate zones of Alaska, and to understand the factors responsible for that variability in order to predict the response of the ice to future climate change. Lake ice growth and decay variables include freezing, ice thickness, modes of thickening [congelation ice, snow ice], and break-up. This is a larger and more comprehensive set of variables than has been considered previously and they integrate the effects of both temperature and precipitation variability. Successful completion of this study will yield well-validated lake ice growth and decay model that will enable us to identify the key factors responsible for the variability of lake ice growth and decay. This will fill a major gap in the knowledge and understanding of the response of the Arctic and sub-Arctic cryosphere to past climate variability and change, and the prediction of future response. This will benefit physical, chemical, and biological limnologists, and ecological andwater resource managers. Teacher and student participation will give them a better appreciation for teaching and learning in the local context, an understanding of the scientific process, and interesting and relevant examples of the impact of climate variability and change on Alaska physical processes and interactions.