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Humidity trends imply increased sensitivity to clouds in a warming Arctic.

https://arctichealth.org/en/permalink/ahliterature268126
Source
Nat Commun. 2015;6:10117
Publication Type
Article
Author
Christopher J Cox
Von P Walden
Penny M Rowe
Matthew D Shupe
Source
Nat Commun. 2015;6:10117
Language
English
Publication Type
Article
Abstract
Infrared radiative processes are implicated in Arctic warming and sea-ice decline. The infrared cloud radiative effect (CRE) at the surface is modulated by cloud properties; however, CRE also depends on humidity because clouds emit at wavelengths that are semi-transparent to greenhouse gases, most notably water vapour. Here we show how temperature and humidity control CRE through competing influences between the mid- and far-infrared. At constant relative humidity, CRE does not decrease with increasing temperature/absolute humidity as expected, but rather is found to be approximately constant for temperatures characteristic of the Arctic. This stability is disrupted if relative humidity varies. Our findings explain observed seasonal and regional variability in Arctic CRE of order 10?W?m(-2). With the physical properties of Arctic clouds held constant, we calculate recent increases in CRE of 1-5?W?m(-2) in autumn and winter, which are projected to reach 5-15?W?m(-2) by 2050, implying increased sensitivity of the surface to clouds.
PubMed ID
26657324 View in PubMed
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Winter storms accelerate the demise of sea ice in the Atlantic sector of the Arctic Ocean.

https://arctichealth.org/en/permalink/ahliterature301286
Source
Sci Rep. 2019 Jun 25; 9(1):9222
Publication Type
Journal Article
Date
Jun-25-2019
Author
Robert M Graham
Polona Itkin
Amelie Meyer
Arild Sundfjord
Gunnar Spreen
Lars H Smedsrud
Glen E Liston
Bin Cheng
Lana Cohen
Dmitry Divine
Ilker Fer
Agneta Fransson
Sebastian Gerland
Jari Haapala
Stephen R Hudson
A Malin Johansson
Jennifer King
Ioanna Merkouriadi
Algot K Peterson
Christine Provost
Achim Randelhoff
Annette Rinke
Anja Rösel
Nathalie Sennéchael
Von P Walden
Pedro Duarte
Philipp Assmy
Harald Steen
Mats A Granskog
Author Affiliation
Norwegian Polar Institute, Fram Centre, Tromsø, Norway. Robert.Graham@npolar.no.
Source
Sci Rep. 2019 Jun 25; 9(1):9222
Date
Jun-25-2019
Language
English
Publication Type
Journal Article
Abstract
A large retreat of sea-ice in the 'stormy' Atlantic Sector of the Arctic Ocean has become evident through a series of record minima for the winter maximum sea-ice extent since 2015. Results from the Norwegian young sea ICE (N-ICE2015) expedition, a five-month-long (Jan-Jun) drifting ice station in first and second year pack-ice north of Svalbard, showcase how sea-ice in this region is frequently affected by passing winter storms. Here we synthesise the interdisciplinary N-ICE2015 dataset, including independent observations of the atmosphere, snow, sea-ice, ocean, and ecosystem. We build upon recent results and illustrate the different mechanisms through which winter storms impact the coupled Arctic sea-ice system. These short-lived and episodic synoptic-scale events transport pulses of heat and moisture into the Arctic, which temporarily reduce radiative cooling and henceforth ice growth. Cumulative snowfall from each sequential storm deepens the snow pack and insulates the sea-ice, further inhibiting ice growth throughout the remaining winter season. Strong winds fracture the ice cover, enhance ocean-ice-atmosphere heat fluxes, and make the ice more susceptible to lateral melt. In conclusion, the legacy of Arctic winter storms for sea-ice and the ice-associated ecosystem in the Atlantic Sector lasts far beyond their short lifespan.
PubMed ID
31239470 View in PubMed
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