Annual Mean Arctic Amplification 1970-2020: Observed and Simulated by CMIP6 Climate Models
Annual Mean Arctic Amplification 1970-2020: Observed and Simulated by CMIP6 Climate Models
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DOI：
10.1029/2022gl099371
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发表时间：
2022-07-16
影响因子：
5.2
通讯作者：
Dubey, Manvendra K.
中科院分区：
文献类型：
--
作者：
Chylek, Petr;Folland, Chris;Dubey, Manvendra K.
虽然 1970 年至 2000 年期间，年平均北极增幅 (AA) 指数在 2 到 3 之间变化，但在 21 世纪的前 20 年，其值达到了超过 4。 AA 并没有连续变化，而是在 1986 年和 1999 年左右出现了两次急剧增加。在这些步骤中，全球平均表面气温趋势几乎保持不变，而北极趋势则有所增加。尽管“最佳”CMIP6模型再现了1980年代AA的增长趋势，但它们没有捕捉到1999年后AA的急剧增长趋势，包括其快速阶梯式增长。我们认为，1986 年左右 AA 的第一次急剧增加是由于外部强迫，而接近 1999 年的第二个步骤是由于内部气候变化，模型无法在观测时间内重现。
While the annual mean Arctic Amplification (AA) index varied between two and three during the 1970-2000 period, it reached values exceeding four during the first two decades of the 21st century. The AA did not change in a continuous fashion but rather in two sharp increases around 1986 and 1999. During those steps the mean global surface air temperature trend remained almost constant, while the Arctic trend increased. Although the "best" CMIP6 models reproduce the increasing trend of the AA in 1980s they do not capture the sharply increasing trend of the AA after 1999 including its rapid step-like increase. We propose that the first sharp AA increase around 1986 is due to external forcing, while the second step close to 1999 is due to internal climate variability, which models cannot reproduce in the observed time.