BEIJING, April 12 (Xinhua) – Researchers have reconstructed the Arctic amplification index over the past 1,000 years and found that the index has decreased over time, according to the Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences.
The Arctic has warmed more than twice as much as the global average since the pre-industrial era, a phenomenon known as Arctic strengthening. The Arctic amplification index is the slope of a regression equation that links pan-Arctic and medium-latitude temperature deviations.
The declining Arctic amplification index showed that the Arctic experienced faster variability than the low-lying latitudes over the past millennium, but the difference in variation between the two regions gradually diminished, according to the researchers.
Arctic reinforcement and its driving mechanism is a hot and groundbreaking subject in polar climatology. At present, research on Arctic amplification is mainly limited to its seasonal and intermediate changes in recent decades. Researchers hope to be able to identify the changes in Arctic reinforcement over a longer period of time in order to gain a deeper understanding of its driving mechanism.
Researchers from the Chinese Academy of Sciences, Lund University and the University of Gothenburg in Sweden reconstructed an annual average temperature data for the northern hemisphere over the past millennium by assimilating climate proxy data such as tree rings, ice cores and sea sediments.
The study expanded the time scale for research on Arctic reinforcement from decades to a thousand years and from seasonal to multi-decade.
On a millennial scale, there is a significant correlation between Arctic amplification and the two factors for Atlantic Multidecadal Oscillation and greenhouse gases, according to the study.
The research article has been published in the journal Nature Communications.