Melt onset over Arctic sea ice controlled by atmospheric moisture transport

Abstract The timing of melt onset affects the surface energy uptake throughout the melt season. Yet the processes triggering melt and causing its large interannual variability are not well understood. Here we show that melt onset over Arctic sea ice is initiated by positive anomalies of water vapor,...

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Main Authors: Jonas Mortin, Gunilla Svensson, Rune G. Graversen, Marie‐Luise Kapsch, Julienne C. Stroeve, Linette N. Boisvert
Format: Article
Language:English
Published: Wiley 2016-06-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2016GL069330
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author Jonas Mortin
Gunilla Svensson
Rune G. Graversen
Marie‐Luise Kapsch
Julienne C. Stroeve
Linette N. Boisvert
author_facet Jonas Mortin
Gunilla Svensson
Rune G. Graversen
Marie‐Luise Kapsch
Julienne C. Stroeve
Linette N. Boisvert
author_sort Jonas Mortin
collection DOAJ
description Abstract The timing of melt onset affects the surface energy uptake throughout the melt season. Yet the processes triggering melt and causing its large interannual variability are not well understood. Here we show that melt onset over Arctic sea ice is initiated by positive anomalies of water vapor, clouds, and air temperatures that increase the downwelling longwave radiation (LWD) to the surface. The earlier melt onset occurs; the stronger are these anomalies. Downwelling shortwave radiation (SWD) is smaller than usual at melt onset, indicating that melt is not triggered by SWD. When melt occurs early, an anomalously opaque atmosphere with positive LWD anomalies preconditions the surface for weeks preceding melt. In contrast, when melt begins late, clearer than usual conditions are evident prior to melt. Hence, atmospheric processes are imperative for melt onset. It is also found that spring LWD increased during recent decades, consistent with trends toward an earlier melt onset.
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series Geophysical Research Letters
spelling doaj-art-abd37889cfaf4811880f868cbceed99e2025-08-20T03:10:24ZengWileyGeophysical Research Letters0094-82761944-80072016-06-0143126636664210.1002/2016GL069330Melt onset over Arctic sea ice controlled by atmospheric moisture transportJonas Mortin0Gunilla Svensson1Rune G. Graversen2Marie‐Luise Kapsch3Julienne C. Stroeve4Linette N. Boisvert5Department of Meteorology and Bolin Centre for Climate Research Stockholm University Stockholm SwedenDepartment of Meteorology and Bolin Centre for Climate Research Stockholm University Stockholm SwedenDepartment of Physics and Technology UiT Arctic University of Norway Tromsø NorwayMax‐Planck‐Institute for Meteorology Hamburg GermanyNational Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder Boulder Colorado USAEarth System Science Interdisciplinary Center University of Maryland College Park Maryland USAAbstract The timing of melt onset affects the surface energy uptake throughout the melt season. Yet the processes triggering melt and causing its large interannual variability are not well understood. Here we show that melt onset over Arctic sea ice is initiated by positive anomalies of water vapor, clouds, and air temperatures that increase the downwelling longwave radiation (LWD) to the surface. The earlier melt onset occurs; the stronger are these anomalies. Downwelling shortwave radiation (SWD) is smaller than usual at melt onset, indicating that melt is not triggered by SWD. When melt occurs early, an anomalously opaque atmosphere with positive LWD anomalies preconditions the surface for weeks preceding melt. In contrast, when melt begins late, clearer than usual conditions are evident prior to melt. Hence, atmospheric processes are imperative for melt onset. It is also found that spring LWD increased during recent decades, consistent with trends toward an earlier melt onset.https://doi.org/10.1002/2016GL069330Arctic sea icemelt onsetremote sensingclimate variabilitypolar meteorology
spellingShingle Jonas Mortin
Gunilla Svensson
Rune G. Graversen
Marie‐Luise Kapsch
Julienne C. Stroeve
Linette N. Boisvert
Melt onset over Arctic sea ice controlled by atmospheric moisture transport
Geophysical Research Letters
Arctic sea ice
melt onset
remote sensing
climate variability
polar meteorology
title Melt onset over Arctic sea ice controlled by atmospheric moisture transport
title_full Melt onset over Arctic sea ice controlled by atmospheric moisture transport
title_fullStr Melt onset over Arctic sea ice controlled by atmospheric moisture transport
title_full_unstemmed Melt onset over Arctic sea ice controlled by atmospheric moisture transport
title_short Melt onset over Arctic sea ice controlled by atmospheric moisture transport
title_sort melt onset over arctic sea ice controlled by atmospheric moisture transport
topic Arctic sea ice
melt onset
remote sensing
climate variability
polar meteorology
url https://doi.org/10.1002/2016GL069330
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AT runeggraversen meltonsetoverarcticseaicecontrolledbyatmosphericmoisturetransport
AT marieluisekapsch meltonsetoverarcticseaicecontrolledbyatmosphericmoisturetransport
AT juliennecstroeve meltonsetoverarcticseaicecontrolledbyatmosphericmoisturetransport
AT linettenboisvert meltonsetoverarcticseaicecontrolledbyatmosphericmoisturetransport