@article{31929b3fce2c40a19bc98a2f0c9e650b,
title = "Strong summer atmospheric rivers trigger Greenland ice sheet melt through spatially varying surface energy balance and cloud regimes",
abstract = "Mass loss from the Greenland Ice Sheet (GrIS) has accelerated over the past two decades, coincident with rapid Arctic warming and increasing moisture transport over Greenland by atmospheric rivers (ARs). Summer ARs affecting western Greenland trigger GrIS melt events, but the physical mechanisms through which ARs induce melt are not well understood. This study elucidates the coupled surface-atmosphere processes by which ARs force GrIS melt through analysis of the surface energy balance (SEB), cloud properties, and local- to synoptic-scale atmospheric conditions during strong summer AR events affecting western Greenland. ARs are identified in MERRA-2 reanalysis (1980-2017) and classified by integrated water vapor transport (IVT) intensity. SEB, cloud, and atmospheric data from regional climate model, observational, reanalysis, and satellite-based datasets are used to analyze melt-inducing physical processes during strong,.90th percentile ''AR901'' events. Near AR ''landfall,'' AR901 days feature increased cloud cover that reduces net shortwave radiation and increases net longwave radiation. As these oppositely signed radiative anomalies partly cancel during AR901 events, increased melt energy in the ablation zone is primarily provided by turbulent heat fluxes, particularly sensible heat flux. These turbulent heat fluxes are driven by enhanced barrier winds generated by a stronger synoptic pressure gradient combined with an enhanced local temperature contrast between cool over-ice air and the anomalously warm surrounding atmosphere. During AR901 events in northwest Greenland, anomalous melt is forced remotely through a clear-sky foehn regime produced by downslope flow in eastern Greenland.",
author = "Mattingly, {Kyle S.} and Mote, {Thomas L.} and Xavier Fettweis and {van As}, Dirk and {van Tricht}, Kristof and Stef Lhermitte and Claire Pettersen and Fausto, {Robert S.}",
note = "Funding Information: Acknowledgments. The authors thank Stefan Hofer for assistance with the MAR cloud data. K. S. Mattingly was supported by a NASA Earth and Space Science Fellowship (NASA Grant NNX16A022H). D. van As and R. S. Fausto were supported by the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) of the Geological Survey of Denmark and Greenland (GEUS), funded by the Danish Ministry of Climate, Energy and Utilities. C. Pettersen was supported by NSF Grants 1304544 and 1801318. Computational resources for MAR simulations were provided by the Consortium des {\'E}quipements de Calcul Intensif (C{\'E}CI), funded by the Fonds de la Recherche Scientifique de Belgique (F.R.S.FNRS) under grant 2.5020.11 and the Tier-1 supercomputer (Zenobe) of the F{\'e}d{\'e}ration Wallonie Bruxelles infrastructure funded by the Walloon Region under Grant Agreement 1117545. ERA5 data are available from the Copernicus Climate Change Service Climate Data Store (https://cds.climate. copernicus.eu) and MERRA-2 data are available from the NASA Goddard Earth Sciences Data and Information Services Center (https://disc.gsfc.nasa.gov/). MAR data are available at ftp://climato.be/fettweis/MARv3.9/Greenland/ ERAint_1979-2018_7_5km/. Data from the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) and the Greenland Analogue Project (GAP) are provided by GEUS at http://www.promice.dk. Summit Station LWP data are available from the NOAA Earth System Research Laboratory{\textquoteright}s Physical Sciences Division (PSD): https://www.esrl.noaa.gov/psd/arctic/observatories/ summit/. Hybrid RACMO-satellite cloud data are available upon request from Kristof Van Tricht and Stef Lhermitte. Publisher Copyright: {\textcopyright} 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).",
year = "2020",
month = aug,
day = "15",
doi = "10.1175/JCLI-D-19-0835.1",
language = "English",
volume = "33",
pages = "6809--6832",
journal = "Journal of Climate",
issn = "0894-8755",
publisher = "American Meteorological Society",
number = "16",
}