Understanding and Constraining Future Arctic Climate Change

0714083UCLAFunds用于理解和约束当前一代气候模式中重要的北冰洋海冰反照率反馈(SIAF)。为了减少模型中反馈模拟之间的差异，有必要确定可用于评估反馈的真实性的观测约束。这里的核心困难在于，反馈是未来气候的方面，不能直接观察到。为了规避这一点，首席调查员(PI)的战略是量化模拟的SIAF强度，因为它影响到温带外最明显和最突出的外部强迫气候变化的例子--当前气候的季节周期。如果当前季节周期中模拟的SIAF强度是气候变化背景下反馈强度的一个很好的预测指标，那么对当前季节周期中反馈的观测限制应该直接导致未来气候预测中反馈强度的模型间扩散减少。PI以前关于雪反照率反馈的工作似乎就是这种情况，并概述了一种考虑到反馈的特殊性为SIAF产生类似结果的战略。与这一努力相对应的一项重要工作将是确定当前气候模拟的哪些方面对SIAF的强度及其模型间传播影响最大。PI开发了一个数学框架，以便于根据模型输出进行这些诊断。预计这项工作将侧重于海冰反照率的参数化，但也将研究北极云在调节SIAF方面的作用，以及海-海-冰相互作用的作用。

Hall 0714083UCLAFunds are provided to understand and constrain the important arctic sea-ice-albedo feedback (SIAF) in the current generation of climate models. To reduce the spread between simulations of feedbacks in models, it is necessary to identify observational constraints that can be used to evaluate the feedback's realism. The central difficulty here is that the feedbacks are aspects of future climate, and cannot be observed directly. To circumvent this, the strategy of the principal investigator (PI) is to quantify simulated SIAF strength as it impacts the most observable and prominent example of externally-forced climate variability in the extratropics - the current climate's seasonal cycle. If simulated SIAF strength in the current seasonal cycle is an excellent predictor of feedback strength in the climate change context, then observational constraints on the feedback in the current seasonal cycle should lead directly to reductions in the intermodel spread of feedback strength in the future climate predictions. This appears to have been the case with the PI's previous work on snow albedo feedback, and a strategy for producing similar results for SIAF that takes into account the feedback's peculiarities has been outlined. An essential counterpart to this effort will be determining which aspects of current climate simulations influence SIAF strength and its intermodel spread the most. The PI has developed a mathematical framework to facilitate these diagnoses from model output. It is anticipated that the work will focus on sea ice albedo parameterizations, but will also examine the role of arctic clouds in modulating SIAF, as well as the role of ocean-sea-ice interaction.