Abstract
Eurasia has experienced more frequent bitter winters over the past two decades, which concurred with a prominent “Warm Arctic-Cold Siberia” (WACS) pattern that is unexpected from global warming. Here we show, by analysis of 117-year observations and climate model's millennial simulations, that the WACS is an internal mode of winter temperature variability, which cannot be excited by greenhouse gases and solar forcing. Observational and simulated results suggest that frequent occurrences of that WACS pattern are instigated by warm phases of Atlantic Multidecadal Oscillation (AMO). North Atlantic warming may activate the WACS by generating a background Atlantic-Eurasian wave train characterized by enhanced Ural Mountain ridge and East Asian trough, which is conducive to recurrent WACS pattern. The wave train-induced the Barents Sea ice melting can act as an amplifier, reinforcing the WACS. Although increased greenhouse gases favor a uniform warming pattern, they may contribute to WACS formation by affecting AMO.
| Original language | English |
|---|---|
| Article number | e2019GL086248 |
| Journal | Geophysical Research Letters |
| Volume | 47 |
| Issue number | 9 |
| DOIs | |
| State | Published - May 16 2020 |
Funding
The authors thank the anonymous reviewers for their thorough and constructive comments that lead to an improved manuscript. This research is jointly supported by the National Key Research and Development Program of China (2016YFA0600401) and National Natural Science Foundation of China (41420104002, 41971108, 41671197, 41971021). the financial support from the program of China Scholarships Council (NO. 201806860029). The CESM‐LME data were generated by the CESM Paleoclimate Working Group at NACR. This is publication No. 10969 of the School of Ocean and Earth Science and Technology, publication No. 1441 of the International Pacific Research Center and publication No. 305 of the Earth System Modeling Center. The authors thank the anonymous reviewers for their thorough and constructive comments that lead to an improved manuscript. This research is jointly supported by the National Key Research and Development Program of China (2016YFA0600401) and National Natural Science Foundation of China (41420104002, 41971108, 41671197, 41971021). the financial support from the program of China Scholarships Council (NO. 201806860029). The CESM-LME data were generated by the CESM Paleoclimate Working Group at NACR. This is publication No. 10969 of the School of Ocean and Earth Science and Technology, publication No. 1441 of the International Pacific Research Center and publication No. 305 of the Earth System Modeling Center.
Keywords
- AMO
- Asian winter monsoon
- greenhouse gases forcing
- internal mode of variability
- multi-decadal variations
- “Warm Arctic-Cold Siberia” pattern