Constraining the Date of a Seasonally Ice‐Free Arctic Using a Simple Model
Constraining the Date of a Seasonally Ice‐Free Arctic Using a Simple Model
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DOI：
10.1029/2021gl094309
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发表时间：
2021-05
影响因子：
5.2
通讯作者：
D. Bonan;T. Schneider;I. Eisenman;Robert C.J. Wills
中科院分区：
文献类型：
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作者：
D. Bonan;T. Schneider;I. Eisenman;Robert C.J. Wills
最先进的气候模型模拟了21世纪北极海冰面积（SIA）预计下降的大范围。在这里，我们使用一个简单的模型，近似未来的SIA的基础上，目前的SIA和敏感性的SIA北极温度诊断这种模型间传播的原因。该模型占模型间方差的70%-95%，其中大部分价差来自当前偏差。其余的传播来自北极变暖的模型间差异，部分原因来自当地海冰敏感性的差异。与无约束的预测相比，使用观测来约束预测将北极无冰的概率向前移动了10-35年。在高排放情景下，无冰的北极可能（> 66%的概率）在2036年至2056年9月之间以及2050年至2068年7月至10月之间出现。在中等排放情景下，“可能”的日期发生在2040年至2062年的9月，以及21世纪的7月至10月。
State‐of‐the‐art climate models simulate a large spread in the projected decline of Arctic sea‐ice area (SIA) over the 21st century. Here we diagnose causes of this intermodel spread using a simple model that approximates future SIA based on present SIA and the sensitivity of SIA to Arctic temperatures. This model accounts for 70%–95% of the intermodel variance, with the majority of the spread arising from present‐day biases. The remaining spread arises from intermodel differences in Arctic warming, with some contribution from differences in the local sea‐ice sensitivity. Using observations to constrain the projections moves the probability of an ice‐free Arctic forward by 10–35 years when compared to unconstrained projections. Under a high‐emissions scenario, an ice‐free Arctic will likely ( > 66% probability) occur between 2036 and 2056 in September and between 2050 and 2068 from July to October. Under a medium‐emissions scenario, the “likely” date occurs between 2040 and 2062 in September and much later in the 21st century from July to October.