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Extensive fires in southeastern Siberian permafrost linked to preceding Arctic Oscillation.

https://arctichealth.org/en/permalink/ahliterature307310
Source
Sci Adv. 2020 01; 6(2):eaax3308
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
01-2020
Author
Jin-Soo Kim
Jong-Seong Kug
Su-Jong Jeong
Hotaek Park
Gabriela Schaepman-Strub
Author Affiliation
School of GeoSciences, University of Edinburgh, Edinburgh, UK.
Source
Sci Adv. 2020 01; 6(2):eaax3308
Date
01-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Abstract
Carbon release through boreal fires could considerably accelerate Arctic warming; however, boreal fire occurrence mechanisms and dynamics remain largely unknown. Here, we analyze fire activity and relevant large-scale atmospheric conditions over southeastern Siberia, which has the largest burned area fraction in the circumboreal and high-level carbon emissions due to high-density peatlands. It is found that the annual burned area increased when a positive Arctic Oscillation (AO) takes place in early months of the year, despite peak fire season occurring 1 to 2 months later. A local high-pressure system linked to the AO drives a high-temperature anomaly in late winter, causing premature snowmelt. This causes earlier ground surface exposure and drier ground in spring due to enhanced evaporation, promoting fire spreading. Recently, southeastern Siberia has experienced warming and snow retreat; therefore, southeastern Siberia requires appropriate fire management strategies to prevent massive carbon release and accelerated global warming.
PubMed ID
31934623 View in PubMed
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Increasing riverine heat influx triggers Arctic sea ice decline and oceanic and atmospheric warming.

https://arctichealth.org/en/permalink/ahliterature304273
Source
Sci Adv. 2020 Nov; 6(45):
Publication Type
Journal Article
Date
Nov-2020
Author
Hotaek Park
Eiji Watanabe
Youngwook Kim
Igor Polyakov
Kazuhiro Oshima
Xiangdong Zhang
John S Kimball
Daqing Yang
Author Affiliation
Institute of Arctic Climate and Environmental Research, JAMSTEC, Yokosuka, Japan. park@jamstec.go.jp.
Source
Sci Adv. 2020 Nov; 6(45):
Date
Nov-2020
Language
English
Publication Type
Journal Article
Abstract
Arctic river discharge increased over the last several decades, conveying heat and freshwater into the Arctic Ocean and likely affecting regional sea ice and the ocean heat budget. However, until now, there have been only limited assessments of riverine heat impacts. Here, we adopted a synthesis of a pan-Arctic sea ice-ocean model and a land surface model to quantify impacts of river heat on the Arctic sea ice and ocean heat budget. We show that river heat contributed up to 10% of the regional sea ice reduction over the Arctic shelves from 1980 to 2015. Particularly notable, this effect occurs as earlier sea ice breakup in late spring and early summer. The increasing ice-free area in the shelf seas results in a warmer ocean in summer, enhancing ocean-atmosphere energy exchange and atmospheric warming. Our findings suggest that a positive river heat-sea ice feedback nearly doubles the river heat effect.
PubMed ID
33158866 View in PubMed
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