人类活动对全球气候产生了深远的影响，然而如何量化人类活动的贡献一直是气候变化研究领域的难点问题。自20世纪90年代中期以来，在人口密集的欧亚大陆夏季气温呈现出显著的非均匀性增暖现象，欧洲-西亚和东北亚的变暖幅度较大，而中亚地区的变暖幅度较小，这种独特的三极变暖形态和成因引起了科学界的广泛关注。
研究发现，自1950年以来欧亚地区夏季气温的年代际变化是由内部变率和外强迫共同导致，其中欧洲-西亚和东亚地区超过一半的变化是由外部强迫（即温室气体和气溶胶）贡献，而不是主要由气候系统内部自然变率（如大西洋多年代际变率，AMO）主导。研究成果不仅为理解欧亚夏季气温的年代际变化机理提供了新证据，也进一步证实了人类活动有关的外强迫对欧洲-西亚和东北亚的影响。
以上工作由院陆气相互作用团队与美国纽约州立大学等科学家合作完成，相关成果发表于AGU期刊《Geophysical Research Letters》，研究工作受到国家自然科学基金项目（42088101，42075022，41625019）资助。
Figure 1. (a) Spatial patterns and (b) temporal variations (black line) of the leading EOF (61% variance) of the linearly detrended and smoothed JJA SAT (OBS*) from CRU TS v4.04 over Eurasia from 1950 to 2014. Also shown in (b) are the standardized, smoothed AMO (gray dashed line) and the Silk Road Pattern (SRP) indices (gray solid line). (c) Same as (a) but for the internal variability (IV) component in JJA SAT (44% variance), and its principal component (PC) is shown as the blue line in (b). (d) Regionally-averaged time series of the smoothed JJA SAT anomalies (°C) from the OBS*, IV and EX (externally-forced component) over Europe-west Asia (EU, solid lines) and East Asia (EA, dashed lines). (e) Same as (a) but for the EX component (89% variance), and its PC is shown as the red line in (b). (f) Same as (d), but for Central Asia (CA). The outlined boxes in (a) represent the EU (0°–50°E, 30–60°N), CA (55°–80°E, 35–55°N) and EA (85°–120°E, 30°–60°N), respectively. Also shown in (f) is the standardized, smoothed IPO index (gray line). The last 9 years, plotted using dotted lines in (b, d, f), used mirrored data in the filtering and thus are less reliable.
相关文献：
Hua Wenjian, Qin Minhua, Dai Aiguo, Zhou Liming, Chen Haishan, Zhang Wangxin. 2021. Reconciling human and natural drivers of the tripole pattern of multidecadal summer temperature variations over Eurasia. Geophysical Research Letters, 48(14), e2021GL093971. https://doi.org/10.1029/2021GL093971
Hua Wenjian, Dai Aiguo, Zhou Liming, Qin Minhua, Chen Haishan. 2019. An externally-forced decadal rainfall seesaw pattern over the Sahel and southeast Amazon. Geophysical Research Letters, 46(2), 923–932.https://doi.org/10.1029/2018GL081406
