Decreasing subseasonal temperature variability in the northern extratropics attributed to human influence
Decreasing subseasonal temperature variability in the northern extratropics attributed to human influence
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DOI：
10.1038/s41561-021-00826-w
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发表时间：
2021-10-01
影响因子：
18.3
通讯作者：
Screen, James A.
中科院分区：
文献类型：
--
作者：
Blackport, Russell;Fyfe, John C.;Screen, James A.
亚季节温度变率的变化与极端天气概率的改变有关，并对社会和生态系统产生重要影响。基于2014年前观测的早期研究表明，北半球温带外陆地上的亚季节温度变率普遍下降。然而，这些变化仅限于特定的地区和季节，统计意义有限，人类影响尚不确定。在这里，我们使用最新的观测和气候模型模拟显示，最近在北半球温带地区出现了人类指纹或亚季节变化的变化模式。指纹特征降低了秋季北部高纬度地区陆地上近地表气温的变化，冬季进一步延伸到中纬度地区。利用大型单强迫模式试验，我们将气温变率降低的模式主要归因于人为温室气体浓度的增加，人为气溶胶起次要作用。我们的结果表明，人类的影响现在可以在半球范围内的日常温度变率中检测到，并促使人们研究温度波动减少对社会和生态系统的影响。根据使用大量气候模式模拟的归因分析，人为温室气体排放是观察到的北部温带地区亚季节温度变率下降的原因。
Changes in subseasonal temperature variability are linked with the altered probability of weather extremes and have important impacts on society and ecological systems. Earlier studies based on observations up to 2014 have shown a general decrease in subseasonal temperature variability over Northern Hemisphere extratropical land. However, these changes have been confined to specific regions and seasons, have limited statistical significance and human influence is yet to be determined. Here we show using up-to-date observations and climate model simulations that a human fingerprint, or pattern of change, in subseasonal variability has recently emerged over the Northern Hemisphere extratropics. The fingerprint features decreased near-surface air temperature variability over land in the high-northern latitudes in autumn, further extending into mid-latitudes in winter. Using large ensembles of single-forcing model experiments, we attribute the pattern of reduced temperature variability primarily to increased anthropogenic greenhouse gas concentrations, with anthropogenic aerosols playing a secondary role. Our results reveal that human influence is now detectable in hemispheric-wide day-to-day temperature variability and motivates research into the impacts of reduced temperature volatility on societal and ecological systems.Anthropogenic greenhouse gas emissions are responsible for the observed decrease in subseasonal temperature variability in the northern extratropics, according to an attribution analysis using a large ensemble of climate model simulations.