During the past few years, a cooling trend in Eurasia and a warming trend in the Arctic was observed by various sources. The presence of a cause-and-effect relationship in this pattern is highly debated for a long time.
Schematic view of the multisphere interactions. Image Credit: Yongkun, Xie
A study reported in the journal Climate Dynamics, by scientists from the Institute of Atmospheric Physics of the Chinese Academy of Sciences and Lanzhou University, provides clues to the question. Their results indicate that the Arctic climate is considered to be one of the factors pushing the entire trend and decadal changeability of Eurasian temperature.
The scientists found a dynamic and thermodynamic coupling view into the way the Arctic pushes Eurasian climate variability and basic multi-sphere interactions. Besides, a comparison was made between cases in several time scales, that is, overall trend, interannual and decadal variability.
In summer, the key factors in multi-sphere interactions are sea ice, surface solar radiation, and subsurface ocean heat uptake. In winter, the key factors are sea ice, surface sensible heat, diabatic heating of the atmosphere, interaction between the Arctic and mid-latitude, and large-scale circulation.
Dr Yongkun Xie, Study Lead Author, Collaborative Innovation Center for Western Ecological Safety, Lanzhou University
The story begins from summer when absorption of solar radiation by the subsurface ocean over the sea ice loss region (Barents-Kara Sea) is improved. Following this, the energy is discharged to the air through sensible heat in winter via vertical diffusion, leading to local circulation anomaly and increased warming.
The powerful background baroclinicity of the air in mid-high latitudes additionally stimulates the interactions taking place between atmospheric circulation and sea surface sensible heat, and ultimately produces the anticyclonic circulation over the Arctic-Eurasia sector and warm Arctic-cold Eurasia (downstream of the improved Arctic warming) pattern.
The comprehensive mechanisms from the summertime Earth’s surface and subsurface ocean to the wintertime atmosphere suggests a driving role of the Arctic.
Yimin Liu, Study Corresponding Author and Professor, Institute of Atmospheric Physics, Chinese Academy of Sciences
Several studies that were performed earlier obtained conclusions by generalizing interannual variability to overall trends, and hence resulted in much debate. The study might explain this dispute by indicating that the situation in interannual variability is highly complicated compared to the decadal variability and overall trend. It is due to the persistence of the impact of summertime sea ice on wintertime climate variation is weak relating to interannual variability.
This work was financially supported by the National Natural Science Foundation of China.
Journal Reference:
Xie, Y., et al. (2021) A dynamic and thermodynamic coupling view of the linkages between Eurasian cooling and Arctic warming. Climate Dynamics. doi.org/10.1007/s00382-021-06029-8.
Source: https://english.cas.cn/