Cloud-driven modulations of Greenland ice sheet surface melt

Masashi Niwano, Akihiro Hashimoto, Teruo Aoki

Research output: Contribution to journalArticle

Abstract

Clouds have been recognized to enhance surface melt on the Greenland Ice Sheet (GrIS). However, quantitative estimates of the effects of clouds on the GrIS melt area and ice-sheet-wide surface mass balance are still lacking. Here we assess the effects of clouds with a state-of-the-art regional climate model, conducting a numerical sensitivity test in which adiabatic atmospheric conditions as well as zero cloud water/ice amounts are assumed (i.e., clear-sky conditions), although the precipitation rate is the same as in the control all-sky simulation. By including or excluding clouds, we quantify time-integrated feedbacks for the first time. We find that clouds were responsible for a 3.1%, 0.3%, and 0.7% increase in surface melt extent (of the total GrIS area) in 2012, 2013, and 2014, respectively. During the same periods, clouds reduced solar heating and thus daily runoff by 1.6, 0.8, and 1.0 Gt day−1, respectively: clouds did not enhance surface mass loss. In the ablation areas, the presence of clouds results in a reduction of downward latent heat flux at the snow/ice surface so that much less energy is available for surface melt, which highlights the importance of indirect time-integrated feedbacks of cloud radiative effects.

Original languageEnglish
Article number10380
JournalScientific reports
Volume9
Issue number1
DOIs
Publication statusPublished - Dec 1 2019

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Greenland
Ice Cover
Ice
Snow
Climate
Heating
Hot Temperature
Water

ASJC Scopus subject areas

  • General

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Cloud-driven modulations of Greenland ice sheet surface melt. / Niwano, Masashi; Hashimoto, Akihiro; Aoki, Teruo.

In: Scientific reports, Vol. 9, No. 1, 10380, 01.12.2019.

Research output: Contribution to journalArticle

Niwano, Masashi ; Hashimoto, Akihiro ; Aoki, Teruo. / Cloud-driven modulations of Greenland ice sheet surface melt. In: Scientific reports. 2019 ; Vol. 9, No. 1.
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abstract = "Clouds have been recognized to enhance surface melt on the Greenland Ice Sheet (GrIS). However, quantitative estimates of the effects of clouds on the GrIS melt area and ice-sheet-wide surface mass balance are still lacking. Here we assess the effects of clouds with a state-of-the-art regional climate model, conducting a numerical sensitivity test in which adiabatic atmospheric conditions as well as zero cloud water/ice amounts are assumed (i.e., clear-sky conditions), although the precipitation rate is the same as in the control all-sky simulation. By including or excluding clouds, we quantify time-integrated feedbacks for the first time. We find that clouds were responsible for a 3.1{\%}, 0.3{\%}, and 0.7{\%} increase in surface melt extent (of the total GrIS area) in 2012, 2013, and 2014, respectively. During the same periods, clouds reduced solar heating and thus daily runoff by 1.6, 0.8, and 1.0 Gt day−1, respectively: clouds did not enhance surface mass loss. In the ablation areas, the presence of clouds results in a reduction of downward latent heat flux at the snow/ice surface so that much less energy is available for surface melt, which highlights the importance of indirect time-integrated feedbacks of cloud radiative effects.",
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