Using the current seasonal cycle to constrain snow albedo feedback in future climate change
Using the current seasonal cycle to constrain snow albedo feedback in future climate change
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DOI：
10.1029/2005gl025127
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发表时间：
2006-02-03
影响因子：
5.2
通讯作者：
Qu, X
中科院分区：
文献类型：
--
作者：
Hall, A;Qu, X
气候反馈模拟的差异是气候模式对人为强迫的温度响应显著差异的来源。在人口稠密的北方陆块中，雪反馈对气候变化预测特别重要。在这里，我们展示了它在当前模型中的优势，表现出三分之一的传播。气候变化中反馈强度的这些大的模式间变化与季节循环背景下反馈强度的巨大模式间变化几乎完全相关。此外，可以测量真实的季节周期中的反馈强度，并将其与模拟值进行比较。这些大多落在观察到的估计范围之外，这表明许多模型在季节性周期背景下有不切实际的降雪反馈。由于季节循环中模拟的反馈强度与气候变化密切相关，消除季节循环中的模式误差将直接导致气候变化中反馈强度传播的减少。虽然这种与观测结果的比较可能会使模型处于过度苛刻的环境中，因为观测到的估计值存在难以量化的不确定性，但我们的研究结果为有针对性地观测季节周期制定了明确的策略，以减少气候敏感性模拟中的分歧。
Differences in simulations of climate feedbacks are sources of significant divergence in climate models' temperature response to anthropogenic forcing. Snow albedo feedback is particularly critical for climate change prediction in heavily-populated northern hemisphere land masses. Here we show its strength in current models exhibits a factor-of-three spread. These large intermodel variations in feedback strength in climate change are nearly perfectly correlated with comparably large intermodel variations in feedback strength in the context of the seasonal cycle. Moreover, the feedback strength in the real seasonal cycle can be measured and compared to simulated values. These mostly fall outside the range of the observed estimate, suggesting many models have an unrealistic snow albedo feedback in the seasonal cycle context. Because of the tight correlation between simulated feedback strength in the seasonal cycle and climate change, eliminating the model errors in the seasonal cycle will lead directly to a reduction in the spread of feedback strength in climate change. Though this comparison to observations may put the models in an unduly harsh light because of uncertainties in the observed estimate that are difficult to quantify, our results map out a clear strategy for targeted observation of the seasonal cycle to reduce divergence in simulations of climate sensitivity.