Blackport Russell, Sigmond Michael, Screen James A
Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada, Victoria, BC, Canada.
Department of Mathematics and Statistics, University of Exeter, Exeter, UK.
Sci Adv. 2024 Oct 4;10(40):eadp1346. doi: 10.1126/sciadv.adp1346. Epub 2024 Oct 2.
An apparent increase in observed cold extremes over recent decades in the northern midlatitudes has been reported, in contrast to robust decreases predicted by climate models. This discrepancy has led to suggestions that models fail to accurately simulate changes in weather patterns caused by Arctic warming. Here, we show that the observed frequency and intensity of midlatitude cold extremes have strongly decreased since 1990 and are consistent with modeled trends. The previously reported increase in cold extremes was overestimated due to an artifact of changing data coverage. We also show that the fraction of land with observed cold extreme increases over recent decades is consistent with model internal variability on top of a near-uniform forced reduction in cold extremes across the midlatitudes. Our results provide strong evidence of a decrease in midlatitude cold extremes over recent decades and consistency between models and observations.
据报道,近几十年来北半球中纬度地区观测到的极端寒冷事件明显增加,这与气候模型预测的显著减少形成对比。这种差异导致有人认为模型未能准确模拟北极变暖引起的天气模式变化。在此,我们表明自1990年以来,中纬度极端寒冷事件的观测频率和强度已大幅下降,且与模型趋势一致。先前报道的极端寒冷事件增加是由于数据覆盖范围变化的人为因素而被高估。我们还表明,近几十年来观测到极端寒冷事件增加的陆地比例与模型内部变率一致,而中纬度地区极端寒冷事件在近乎均匀的强迫减少之上。我们的结果提供了强有力的证据,证明近几十年来中纬度极端寒冷事件减少,以及模型与观测之间的一致性。