scholarly journals Quantifying black carbon deposition over the Greenland ice sheet from forest fires in Canada

2017 ◽  
Vol 44 (15) ◽  
pp. 7965-7974 ◽  
Author(s):  
J. L. Thomas ◽  
C. M. Polashenski ◽  
A. J. Soja ◽  
L. Marelle ◽  
K. A. Casey ◽  
...  
Keyword(s):  
Black Carbon ◽  
Forest Fires ◽  
Carbon Deposition ◽  
Ice Sheet ◽  
Greenland Ice Sheet

scholarly journals Ice sheet mass loss caused by dust and black carbon accumulation

2015 ◽  
Vol 9 (2) ◽  
pp. 2563-2596
Author(s):  
T. Goelles ◽  
C. E. Bøggild ◽  
R. Greve
Keyword(s):  
Mass Loss ◽  
Black Carbon ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Carbon Accumulation ◽  
Model Framework ◽  
Ice Dynamics ◽  
Ablation Area ◽  
Ice Surface ◽  
Surface Melt

Abstract. Albedo is the dominating factor governing surface melt variability in the ablation area of ice sheets and glaciers. Aerosols such as mineral dust and black carbon (soot) accumulate on the ice surface and cause a darker surface and therefore a lower albedo. The dominant source of these aerosols in the ablation area is melt-out of englacial material which has been transported via ice flow. The darkening effect on the ice surface is currently not included in sea level projections, and the effect is unknown. We present a model framework which includes ice dynamics, aerosol transport, aerosol accumulation and the darkening effect on ice albedo and its consequences for surface melt. The model is applied to a simplified geometry resembling the conditions of the Greenland ice sheet, and it is forced by several temperature scenarios to quantify the darkening effect of aerosols on future mass loss. The effect of aerosols depends non-linearly on the temperature rise due to the feedback between aerosol accumulation and surface melt. The effect of aerosols in the year 3000 is up to 12% of additional ice sheet volume loss in the warmest scenario.

Impact of forest fires generated black carbon deposition fluxes in Great Hinggan Mountains (China)

2017 ◽  
Vol 29 (7) ◽  
pp. 2073-2081 ◽  
Author(s):  
Chuanyu Gao ◽  
Jiabao He ◽  
Jinxin Cong ◽  
Shaoqing Zhang ◽  
Guoping Wang
Keyword(s):  
Black Carbon ◽  
Forest Fires ◽  
Carbon Deposition ◽  
Deposition Fluxes

Forty years later: High resolution continuous flow analysis of the Dye3 ice core

2021 ◽  
Author(s):  
Helle Astrid Kjær ◽  
Margaret Harlan ◽  
Paul Vallelonga ◽  
Anders Svensson ◽  
Thomas Blunier ◽  
...  
Keyword(s):  
High Resolution ◽  
Forest Fires ◽  
Continuous Flow ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
The Core ◽  
Continuous Flow Analysis

<div><span><span>The Dye-3 ice core was drilled to bedrock at the Southern part of the central Greenland ice sheet (65°11'N, 43°50'W) in 1979-1981. The southern location is characterized by high accumulation rates compared to more central locations of the ice sheet. Since its drilling, numerous analyses of the core have been performed, and the ice has since been in freezer storage both in the USA and in Denmark.</span></span></div><div><span>In October and November 2019, the remaining ice, two mostly complete sections covering the depths of 1753–1820m and 1865–1918m of the Dye-3 core, were melted during a continuous flow analysis (CFA) campaign at the Physics of Ice, Climate, and Earth (PICE) group at the University of Copenhagen. The data represents both Holocene, Younger Dryas and Glacial sections (GS 5 to 12).</span></div><div> </div><div><span><span>The measured data consist chemistry and impurities contained in the ice, isotopes, as well as analysis of methane and other atmospheric gases. </span></span></div><div><span><span>The chemistry measurements include NH</span></span><span><span><sub>4</sub></span></span><span><span><sup>+</sup></span></span><span><span>, Ca</span></span><span><span><sup>2+</sup></span></span><span><span>, and Na</span></span><span><span><sup>+</sup></span></span><span><span> ions, which besides being influenced by transport, provide information about forest fires, wind-blown dust, and sea ice, respectively, as well as acidity, which aids in the identification of volcanic events contained in the core. The quantity and grain size distribution of insoluble particles was analyzed by means of an Abakus laser particle counter.</span></span></div><div> </div><div><span>We compare the new high-resolution CFA record of dye3 with previous analysis and thus evaluate the progress made over 40 years. Further we compare overlapping time periods with other central Greenland ice cores and discuss spatial patterns in relation to the presented climate proxies.</span></div>

scholarly journals Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model

2012 ◽  
Vol 6 (2) ◽  
pp. 1531-1562 ◽  
Author(s):  
J. H. van Angelen ◽  
J. T. M. Lenaerts ◽  
S. Lhermitte ◽  
X. Fettweis ◽  
P. Kuipers Munneke ◽  
...  
Keyword(s):  
Grain Size ◽  
Mass Balance ◽  
Black Carbon ◽  
Climate Model ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Shortwave Radiation ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Snow Albedo

Abstract. We present a sensitivity study of the surface mass balance (SMB) of the Greenland Ice Sheet, as modeled using a regional atmospheric climate model, to various parameter settings in the albedo parameterization. The snow albedo parameterization uses grain size as a prognostic variable and further depends on cloud cover, solar zenith angle and black carbon concentration. For the control experiment the overestimation of absorbed shortwave radiation (+6 %) at the K-transect (West Greenland) for the period 2004–2009 is considerably reduced compared to the previous density-dependent albedo parameterization (+22 %). To simulate realistic snow albedo values, a small concentration of black carbon is needed. A background ice albedo field derived from MODIS imagery improves the agreement between the modeled and observed SMB gradient along the K-transect. The effect of enhanced retention and refreezing is a decrease of the albedo due to an increase in snow grain size. As a secondary effect of refreezing the snowpack is heated, enhancing melt and further lowering the albedo. Especially in a warmer climate this process is important, since it reduces the refreezing potential of the firn layer covering the Greenland Ice Sheet.

scholarly journals Boreal fire records in Northern Hemisphere ice cores: A review

2016 ◽  
Author(s):  
Michel Legrand ◽  
Joseph McConnell ◽  
Hubertus Fischer ◽  
Eric W. Wolff ◽  
Susanne Preunkert ◽  
...  
Keyword(s):  
High Resolution ◽  
Organic Carbon ◽  
Black Carbon ◽  
Biomass Burning ◽  
Forest Fires ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
High Elevation ◽  
Fire Activity

Abstract. Here we review different attempts made since the early 1990s to reconstruct past forest fire activity using chemical signals recorded in ice cores extracted from the Greenland ice sheet and at a few mid-northern latitude, high-elevation glaciers. We first examined the quality of various inorganic (ammonium, nitrate, potassium) and organic (black carbon, various organic carbon compounds including levoglucosan and numerous carboxylic acids) species proposed as fire proxies in ice, particularly in Greenland. We discuss limitations in their use with respect to the considered time period (recent versus pre-industrial times), their atmospheric lifetime, and the relative importance of other non-biomass burning sources. Different high-resolution records obtained at several Greenland drill sites and covering various timescales, including the last century and Holocene, are discussed. We explore the extent to which atmospheric transport can modulate the record of boreal fires from Canada as recorded in Greenland ice. Ammonium, organic fractions (black carbon as well as organic carbon), and organic compounds like formate and vanillic acid are found to be good proxies for tracing past boreal fires in Greenland ice. We show that use of other species – potassium, nitrate, and carboxylates (except formate) – is complicated by either post-depositional effects or existence of large non-biomass-burning sources. The quality of levoglucosan with respect to other proxies is not addressed here because of the present lack of high-resolution profiles for this species, which does not allow for a fair comparison. Several Greenland ice records of ammonium consistently indicate changing fire activity in Canada in response to past climatic conditions that occurred during the last millennium and since the last large climatic transition. Based on this critical review, we make recommendations for further study to increase reliability of the reconstructed history of forest fires occurring in a given region.

scholarly journals Climate change and forest fires synergistically drive widespread melt events of the Greenland Ice Sheet

2014 ◽  
Vol 111 (22) ◽  
pp. 7964-7967 ◽  
Author(s):  
K. M. Keegan ◽  
M. R. Albert ◽  
J. R. McConnell ◽  
I. Baker
Keyword(s):  
Climate Change ◽  
Forest Fires ◽  
Ice Sheet ◽  
Greenland Ice Sheet

scholarly journals Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model

2012 ◽  
Vol 6 (5) ◽  
pp. 1175-1186 ◽  
Author(s):  
J. H. van Angelen ◽  
J. T. M. Lenaerts ◽  
S. Lhermitte ◽  
X. Fettweis ◽  
P. Kuipers Munneke ◽  
...  
Keyword(s):  
Grain Size ◽  
Mass Balance ◽  
Black Carbon ◽  
Climate Model ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Shortwave Radiation ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Snow Albedo

Abstract. We present a sensitivity study of the surface mass balance (SMB) of the Greenland Ice Sheet, as modeled using a regional atmospheric climate model, to various parameter settings in the albedo scheme. The snow albedo scheme uses grain size as a prognostic variable and further depends on cloud cover, solar zenith angle and black carbon concentration. For the control experiment the overestimation of absorbed shortwave radiation (+6%) at the K-transect (west Greenland) for the period 2004–2009 is considerably reduced compared to the previous density-dependent albedo scheme (+22%). To simulate realistic snow albedo values, a small concentration of black carbon is needed, which has strongest impact on melt in the accumulation area. A background ice albedo field derived from MODIS imagery improves the agreement between the modeled and observed SMB gradient along the K-transect. The effect of enhanced meltwater retention and refreezing is a decrease of the albedo due to an increase in snow grain size. As a secondary effect of refreezing the snowpack is heated, enhancing melt and further lowering the albedo. Especially in a warmer climate this process is important, since it reduces the refreezing potential of the firn layer that covers the Greenland Ice Sheet.

scholarly journals Albedo reduction caused by black carbon and dust accumulation: a quantitive model applied to the western margin of the Greenland ice sheet

2015 ◽  
Vol 9 (1) ◽  
pp. 1345-1381 ◽  
Author(s):  
T. Goelles ◽  
C. E. Bøggild
Keyword(s):  
Black Carbon ◽  
Surface Albedo ◽  
Climate Model ◽  
Mineral Dust ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Surface ◽  
Regional Climate Model Output ◽  
Surface Melt

Abstract. Ice loss due to surface melt of the Greenland ice sheet has increased in recent years. Surface melt in the ablation zone is controlled by atmospheric temperature and surface albedo. Impurities such as mineral dust and black carbon darken the snow and ice surfaces and therefore reduce the surface albedo which leads to more absorbed solar energy and ultimately amplifying melt. These impurities accumulate on the ice surface both from atmospheric fallout and by melt-out of material which was enclosed in the snowpack or the ice compound. A general impurity accumulation model is developed and applied to calculate the surface albedo evolution at two locations in western Greenland. The model is forced either by regional climate model output or by a parameterisation for temperature and precipitation. Simulations identify mineral dust as the main contributor to impurity mass on ice where the dominating part originates from melt out of englacial dust. Daily reduction of impurities is in the range of one per-mille which leads to a residence time of decades on the ice surface. Therefore the impurities have a prolonged effect on surface melt once they are located on the ice surface. The currently englacially stored mineral dust and black carbon will effect future melt and sea level rise and can be studied with the presented model.

The Nioghalvfjerdsfjorden glacier project, North-East Greenland: a study of ice sheet response to climatic change

1997 ◽  
pp. 95-103 ◽  
Author(s):  
Henrik Højmark Thomsen ◽  
Niels Reeh ◽  
Ole B. Olesen ◽  
Carl Egede Bøggilde ◽  
Wolfgang Starzer ◽  
...  
Keyword(s):  
Climatic Change ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
East Greenland ◽  
Changing Climate ◽  
North East ◽  
Integrated Research ◽  
Research Themes ◽  
Advance Research ◽  
Inland Ice

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Højmark Thomsen, H., Reeh, N., Olesen, O. B., Egede Bøggilde, C., Starzer, W., Weidick, A., & Higgins, A. K. (1997). The Nioghalvfjerdsfjorden glacier project, North-East Greenland: a study of ice sheet response to climatic change. Geology of Greenland Survey Bulletin, 176, 95-103. https://doi.org/10.34194/ggub.v176.5073 _______________ Glaciological research was initiated in 1996 on the floating glacier tongue filling Nioghalvfjerdsfjorden in NorthEast Greenland (Fig. 1), with the aim of acquiring a better understanding of the response of the Greenland ice sheet (Inland Ice) to changing climate, and the implications for future sea level. The research is part of a three year project (1996–98) to advance research into the basic processes that contribute to changes in the ocean volume with a changing climate. Five nations are participants in the project, which is supported by the European Community (EC) Environment and Climate Programme. The Geological Survey of Denmark and Greenland (GEUS) and the Danish Polar Center are the Danish partners in the project, both with integrated research themes concentrated on and around Nioghalvfjerdsfjorden.

Could climate engineering save the Greenland Ice Sheet?

2016 ◽  
Author(s):  
Patrick J. Applegate ◽  
K. Keller
Keyword(s):  
Sea Level Rise ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Sea Level ◽  
Computer Model ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Upper Atmosphere ◽  
Climate Engineering ◽  
Air Temperatures

Engineering the climate through albedo modification (AM) could slow, but probably would not stop, melting of the Greenland Ice Sheet. Albedo modification is a technology that could reduce surface air temperatures through putting reflective particles into the upper atmosphere. AM has never been tested, but it might reduce surface air temperatures faster and more cheaply than reducing greenhouse gas emissions. Some scientists claim that AM would also prevent or reverse sea-level rise. But, are these claims true? The Greenland Ice Sheet will melt faster at higher temperatures, adding to sea-level rise. However, it's not clear that reducing temperatures through AM will stop or reverse sea-level rise due to Greenland Ice Sheet melting. We used a computer model of the Greenland Ice Sheet to examine its contributions to future sea level rise, with and without AM. Our results show that AM would probably reduce the rate of sea-level rise from the Greenland Ice Sheet. However, sea-level rise would likely continue even with AM, and the ice sheet would not regrow quickly. Albedo modification might buy time to prepare for sea-level rise, but problems could arise if policymakers assume that AM will stop sea-level rise completely.

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