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Are transition season melt events on the Greenland Ice Sheet driven by Baffin Bay sea ice-atmosphere interactions?
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  • Thomas Ballinger,
  • Thomas Mote,
  • Kyle Mattingly,
  • Edward Hanna,
  • Angela Bliss,
  • Dirk van As,
  • Melissa Prieto,
  • Saeideh Gharehchahi,
  • Xavier Fettweis,
  • Brice Noël,
  • Paul Smeets,
  • Mads Ribergaard
Thomas Ballinger
Texas State University

Corresponding Author:tballinger@txstate.edu

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Thomas Mote
University of Georgia
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Kyle Mattingly
University of Georgia
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Edward Hanna
University of Lincoln
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Angela Bliss
NASA Goddard Space Flight Center & University of Maryland
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Dirk van As
Geological Survey of Denmark and Greenland
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Melissa Prieto
Texas State University
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Saeideh Gharehchahi
Texas State University
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Xavier Fettweis
University of Liège
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Brice Noël
Utretcht University
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Paul Smeets
Utretcht University
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Mads Ribergaard
Danish Meteorological Institute
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Abstract

A number of insitu and passive microwave satellite sensors have observed Arctic sea ice and Greenland Ice Sheet (GrIS) mass loss trends over recent decades. Along with sea and land ice declines, above-freezing, near-surface air temperatures are observed earlier in boreal spring and later in autumn thus extending periods of melt beyond the core of summer (JJA). Little is known about whether lengthening periods of open ocean proximate to the ice sheet, for instance, demonstrably effect unseasonal GrIS melt events. Here, a new Baffin Bay sea ice advance dataset is utilized to determine dates of sea ice growth along Greenland’s west coast for the 2011-2015 period. Preceding, multi-scale ocean-atmospheric conditions, including at the Baffin-GrIS interface, are analyzed and linked to unseasonal melt events observed at a series of on-ice automatic weather stations (AWS) along the K-transect in southwest Greenland. The local marine versus synoptic influence on the above and below freezing surface air temperature events is assessed through analyses involving AWS winds, pressure, and humidity observations. These surface observations are further compared against Modele Atmospherique Regional (MAR), Regional Atmospheric Climate Model (RACMO), and ERA-Interim reanalysis fields to understand the airmass origins and (thermo)dynamic drivers of the melt events. Results suggest that the K-transect transition season melt events, primarily in the ablation zone, are strongly affected by ridging atmospheric circulation patterns that transport warm, moist air from lower latitude land-ocean areas toward west Greenland. While local conduction of oceanic surface heat appears to impact coastal air temperatures, consistent with previous studies, marine air incursions from Baffin waters onto the ice sheet are likely obstructed by barrier flows and the pressure gradient-driven katabatic regime off of central Greenland.