scholarly journals Sea ice and pollution-modulated changes in Greenland ice core methanesulfonate and bromine

2017 ◽  
Vol 13 (1) ◽  
pp. 39-59 ◽  
Author(s):  
Olivia J. Maselli ◽  
Nathan J. Chellman ◽  
Mackenzie Grieman ◽  
Lawrence Layman ◽  
Joseph R. McConnell ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Chemical Species ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Arctic Sea Ice ◽  
Sea Ice Extent ◽  
Back Trajectories ◽  
Future Evolution ◽  
Source Regions

Abstract. Reconstruction of past changes in Arctic sea ice extent may be critical for understanding its future evolution. Methanesulfonate (MSA) and bromine concentrations preserved in ice cores have both been proposed as indicators of past sea ice conditions. In this study, two ice cores from central and north-eastern Greenland were analysed at sub-annual resolution for MSA (CH3SO3H) and bromine, covering the time period 1750–2010. We examine correlations between ice core MSA and the HadISST1 ICE sea ice dataset and consult back trajectories to infer the likely source regions. A strong correlation between the low-frequency MSA and bromine records during pre-industrial times indicates that both chemical species are likely linked to processes occurring on or near sea ice in the same source regions. The positive correlation between ice core MSA and bromine persists until the mid-20th century, when the acidity of Greenland ice begins to increase markedly due to increased fossil fuel emissions. After that time, MSA levels decrease as a result of declining sea ice extent but bromine levels increase. We consider several possible explanations and ultimately suggest that increased acidity, specifically nitric acid, of snow on sea ice stimulates the release of reactive Br from sea ice, resulting in increased transport and deposition on the Greenland ice sheet.

scholarly journals Sea ice and pollution-modulated changes in Greenland ice core methanesulfonate and bromine

2016 ◽  
Author(s):  
O. J. Maselli ◽  
N. J. Chellman ◽  
M. Grieman ◽  
L. Layman ◽  
J. R. McConnell ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Chemical Species ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Arctic Sea Ice ◽  
Sea Ice Extent ◽  
Back Trajectories ◽  
Future Evolution ◽  
Source Regions

Abstract. Reconstruction of past changes in Arctic sea ice extent may be critical for understanding its future evolution. Methanesulphonate (MSA) and bromine concentrations preserved in ice cores have both been proposed as indicators of past sea ice conditions. In this study, two ice cores from central and NE Greenland were analysed at sub-annual resolution for MSA (CH3SO3H) and bromine, covering the time period 1750–2010. We examine correlations between ice core MSA and the HadISST1 ICE sea ice dataset and consult back-trajectories to infer the likely source regions. A strong correlation between the low frequency MSA and bromine records during preindustrial times indicates that both chemical species are likely linked to processes occurring on or near sea ice in the same source regions. The positive correlation between ice core MSA and bromine persists until the mid-20th century, when the acidity of Greenland ice begins to increase markedly due to increased fossil fuel emissions. After that time, MSA levels decrease as a result of declining sea ice extent but bromine levels increase. We consider several possible explanations and ultimately suggest that increased acidity, specifically nitric acid, of snow on sea ice stimulates the release of reactive Br from sea ice, resulting in increased transport and deposition on the Greenland ice sheet.

scholarly journals An emerging technique: multi-ice-core multi-parameter correlations with Antarctic sea-ice extent

2011 ◽  
Vol 52 (57) ◽  
pp. 347-354 ◽  
Author(s):  
Sharon B. Sneed ◽  
Paul A. Mayewski ◽  
Daniel A. Dixon
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Chemical Species ◽  
Ice Cores ◽  
Initial Step ◽  
Single Species ◽  
Parameter Study ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Siple Dome

AbstractUsing results stemming from the International Trans-Antarctic Scientific Expedition (ITASE) ice-core array plus data from ice cores from the South Pole and Siple Dome we investigate the use of sodium (Na+), non-sea-salt sulfate (nssSO42–) and methylsulfonate (MS–) as proxies for Antarctic sea-ice extent (SIE). Maximum and mean annual chemistry concentrations for these three species correlate significantly with maximum, mean and minimum annual SIE, offering more information and clarification than single ice-core and single species approaches. Significant correlations greater than 90% exist between Na+ and maximum SIE; nssSO42– with minimum and mean SIE; and MS– with mean SIE. Correlations with SIE within large geographic regions are in the same direction for all ice-core sites for Na+ and nssSO42– but not MS–. All ice cores display an SIE correlation with nssSO42– and MS–, but not all correlate with Na+. This multi-core multi-parameter study provides the initial step in determining which chemical species can be used reliably and in which regions as a building block for embedding other ice-core records. Once established, the resulting temporal and spatial matrix can be used to relate ice extents, atmospheric patterns, biological productivity and site conditions.

scholarly journals A 120 000-year record of sea ice in the North Atlantic?

2019 ◽  
Vol 15 (6) ◽  
pp. 2031-2051 ◽  
Author(s):  
Niccolò Maffezzoli ◽  
Paul Vallelonga ◽  
Ross Edwards ◽  
Alfonso Saiz-Lopez ◽  
Clara Turetta ◽  
...  
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Ice Core ◽  
Arctic Sea Ice ◽  
First Year ◽  
Sea Ice Extent ◽  
Nordic Seas ◽  
The North ◽  
Arctic Sea ◽  
The North Atlantic

Abstract. Although it has been demonstrated that the speed and magnitude of the recent Arctic sea ice decline is unprecedented for the past 1450 years, few records are available to provide a paleoclimate context for Arctic sea ice extent. Bromine enrichment in ice cores has been suggested to indicate the extent of newly formed sea ice areas. Despite the similarities among sea ice indicators and ice core bromine enrichment records, uncertainties still exist regarding the quantitative linkages between bromine reactive chemistry and the first-year sea ice surfaces. Here we present a 120 000-year record of bromine enrichment from the RECAP (REnland ice CAP) ice core, coastal east Greenland, and interpret it as a record of first-year sea ice. We compare it to existing sea ice records from marine cores and tentatively reconstruct past sea ice conditions in the North Atlantic as far north as the Fram Strait (50–85∘ N). Our interpretation implies that during the last deglaciation, the transition from multi-year to first-year sea ice started at ∼17.5 ka, synchronously with sea ice reductions observed in the eastern Nordic Seas and with the increase in North Atlantic ocean temperature. First-year sea ice reached its maximum at 12.4–11.8 ka during the Younger Dryas, after which open-water conditions started to dominate, consistent with sea ice records from the eastern Nordic Seas and the North Icelandic shelf. Our results show that over the last 120 000 years, multi-year sea ice extent was greatest during Marine Isotope Stage (MIS) 2 and possibly during MIS 4, with more extended first-year sea ice during MIS 3 and MIS 5. Sea ice extent during the Holocene (MIS 1) has been less than at any time in the last 120 000 years.

scholarly journals A 200 year sulfate record from 16 Antarctic ice cores and associations with Southern Ocean sea-ice extent

2005 ◽  
Vol 41 ◽  
pp. 155-166 ◽  
Author(s):  
Daniel Dixon ◽  
Paul A. Mayewski ◽  
Susan Kaspari ◽  
Karl Kreutz ◽  
Gordon Hamilton ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ross Sea ◽  
Ice Core ◽  
Ice Cores ◽  
South Pole ◽  
West Antarctica ◽  
The South ◽  
Sea Ice Extent ◽  
West Antarctic ◽  
Low Latitudes

AbstractChemistry data from 16, 50–115m deep, sub-annually dated ice cores are used to investigate spatial and temporal concentration variability of sea-salt (ss) SO42– and excess (xs) SO42– over West Antarctica and the South Pole for the last 200 years. Low-elevation ice-core sites in western West Antarctica contain higher concentrations of SO42– as a result of cyclogenesis over the Ross Ice Shelf and proximity to the Ross Sea Polynya. Linear correlation analysis of 15 West Antarctic ice-core SO42– time series demonstrates that at several sites concentrations of ssSO42– are higher when sea-ice extent (SIE) is greater, and the inverse for xsSO42–. Concentrations of xsSO42– from the South Pole site (East Antarctica) are associated with SIE from the Weddell region, and West Antarctic xsSO42– concentrations are associated with SIE from the Bellingshausen–Amundsen–Ross region. The only notable rise of the last 200 years in xsSO42–, around 1940, is not related to SIE fluctuations and is most likely a result of increased xsSO42– production in the mid–low latitudes and/or an increase in transport efficiency from the mid–low latitudes to central West Antarctica. These high-resolution records show that the source types and source areas of ssSO42– and xsSO42– delivered to eastern and western West Antarctica and the South Pole differ from site to site but can best be resolved using records from spatial ice-core arrays such as the International Trans-Antarctic Scientific Expedition (ITASE).

scholarly journals Climate information preserved in seasonal water isotope at NEEM: relationships with temperature, circulation and sea ice

2018 ◽  
Author(s):  
Minjie Zheng ◽  
Jesper Sjolte ◽  
Florian Adolphi ◽  
Bo Møllesøe Vinther ◽  
Hans Christian Steen-Larsen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Ice Cores ◽  
Principal Component ◽  
Summer Precipitation ◽  
Satellite Observation ◽  
Climate Information ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
Baffin Bay

Abstract. Analyzing seasonally resolved δ18O ice core data can aid the interpretation of the climate information in ice cores, providing also insights into factors governing the δ18O signal that cannot be deciphered by investigating the annual δ18O data only. However, the seasonal isotope signal has not yet to be investigated in northern Greenland, e.g. at the NEEM (North Greenland Eemian Ice Drilling) ice core drill site. Here we analyze seasonally resolved δ18O data from four shallow NEEM ice cores covering the last 150 years. Based on correlation analysis with observed temperature, we attribute about 70 % and 30 % of annual accumulation to summer and winter respectively. The NEEM summer δ18O signal correlates strongly with summer western Greenland coastal temperature and with the first principal component (PC1) of summer δ18O from multiple seasonally resolved ice cores from central/southern Greenland. However, there are no significant correlations between NEEM winter δ18O data and western Greenland coastal winter temperature, or southern/central Greenland winter δ18O PC1. The stronger correlation with temperature during summer and the dominance of summer precipitation skew the annual δ18O signal in NEEM. The strong footprint of temperature in NEEM summer δ18O record also suggests that the summer δ18O record, rather than the winter δ18O record, is a better temperature proxy at the NEEM site. Despite dominant signal of North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) in the central-southern ice cores data, both NAO and AMO exert weak influences on NEEM seasonal δ18O variations. The NEEM seasonal δ18O is found to be highly correlated with Baffin Bay sea ice concentration (SIC) in satellite observation period (1979–2004), suggesting a connection of the sea ice extent with δ18O at NEEM. NEEM winter δ18O significantly correlates with SIC even for the period prior to satellite observation (1901–1978). The NEEM winter δ18O may reflect sea ice variations of Baffin Bay rather than temperature itself. This study shows that seasonally resolved δ18O records, especially for sites with seasonal precipitation bias such as NEEM, provide a better understanding of how changing air temperature and circulation patterns are associated with the variability of the δ18O records.

scholarly journals Observationally constrained reconstruction of 19th to mid-20th century sea-ice extent off eastern Greenland

2018 ◽  
pp. 83-86
Author(s):  
Danielle A.M. Hallé ◽  
Nanna B. Karlsson ◽  
Anne Munck Solgaard ◽  
Camilla S. Andresen
Keyword(s):  
Sea Ice ◽  
Single Point ◽  
Global Radiation ◽  
Greenland Ice Sheet ◽  
Arctic Sea Ice ◽  
Radiation Budget ◽  
Sea Ice Extent ◽  
Observation Area ◽  
Arctic Sea ◽  
Danish Meteorological Institute

Arctic sea ice has a significant impact on the global radiation budget, oceanic and atmospheric circulation and the stability of the Greenland ice sheet (Vaughan et al. 2013). Prior to the era of aircraft and satellite, information on sea-ice extent relied on observations from ships and people living at the coast. This information is a valuable contribution to better understand the history of sea ice. However, the information exists in a range of formats, e.g., sea-ice extent before the late 1800s is typically reported in the literature as an annual index from a single geographical point or as hand-drawn maps. This makes it difficult to assess and compare data across time and space. The combination of digitised historical maps and single-point data makes the information more accessible and provides a record that can help understand the dynamics and processes of the climate and its interactions with the cryosphere (Chapman & Walsh 1993). In this study, maps of sea-ice extent by Koch (1945) were digitised. We use these maps in combination with sea-ice charts from the Danish Meteorological Institute (DMI) and Koch’s sea-ice index from 1820 to 1939, to map estimated sea-ice extent between Iceland and Greenland going back to 1821. This information has not been included in even the most recent databases of Arctic sea ice (Walsh et al. 2015, 2017). Furthermore, we extract time series of sea-ice extent at a number of locations and investigate the relationship between them. Our observation area is along eastern Greenland, between the southern tip of Greenland at 59°46´N northwards to 77°21´N.

scholarly journals Sea-ice feedbacks influence the isotopic signature of Greenland Ice Sheet elevation changes: Last Interglacial HadCM3 simulations

2020 ◽  
Author(s):  
Irene Malmierca-Vallet ◽  
Louise C. Sime ◽  
Paul J. Valdes ◽  
Julia C. Tindall
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Lapse Rate ◽  
Last Interglacial ◽  
Elevation Change ◽  
Elevation Gradients ◽  
Lapse Rates

Abstract. Changes in the Greenland ice sheet (GIS) affect global sea level. Greenland stable water isotope (δ18O) records from ice cores offer information on past changes in the surface of the GIS. Here, we use the isotope-enabled HadCM3 climate model to simulate a set of Last Interglacial (LIG) idealised GIS surface elevation change scenarios focusing on GIS ice core sites. We investigate how δ18O depends on the magnitude and sign of GIS elevation change and evaluate how the response is altered by sea ice changes. We find that modifying GIS elevation induces changes in Northern Hemisphere atmospheric circulation, sea ice and precipitation patterns. These climate feedbacks lead to ice core-averaged isotopic lapse rates of 0.49 ‰ per 100 m for the lowered GIS states and 0.29 ‰ per 100 m for the enlarged GIS states. This is lower than the spatially derived Greenland lapse rates of 0.62–0.72 ‰ per 100 m. These results thus suggest non-linearities in the isotope-elevation relationship, and have consequences for the interpretation of past elevation and climate changes across Greenland. In particular, our results suggest that winter sea ice changes may significantly influence isotopic-elevation gradients: winter sea ice effect can decrease (increase) modelled core-averaged isotopic lapse rate values by about -19 % (and +28 %) for the lowered (enlarged) GIS states respectively. The largest influence of sea ice on δ18O changes is found in coastal regions like the Camp Century site.

scholarly journals Imprint of Arctic sea ice cover in North-Greenland ice cores

2019 ◽  
Author(s):  
Damiano Della Lunga ◽  
Hörhold Maria ◽  
Birthe Twarloh ◽  
Behrens Melanie ◽  
Dallmayr Remi ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Open Water ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
Blowing Snow ◽  
Sea Ice Extent ◽  
Arctic Sea ◽  
Frost Flowers ◽  
North Greenland

Abstract. Sea ice is a key component of the climate system, since it modifies the surface albedo, the radiation balance, as well as the exchange of heat, moisture and gases between the ocean and the overlying atmosphere. Hence, the reconstruction of sea ice cover before the instrumental era and the industrial times is crucial to understand the evolution of Arctic climate in the last millennium and better predict its future evolution. However, identifying relevant paleo proxies in climate archives related to sea ice cover is not straightforward. Ice cores from polar regions offer great potential to provide high-resolution records of Arctic sea ice variability from chemical impurities such as Bromine species, which were recently proposed as indicators of sea ice extent, although their variability might be modulated by regional influences. We here use Bromine and Bromine enrichment of two ice cores form North Greenland (B17 & B26) and investigate its potential as proxy to reconstruct sea ice extent over the period 1363–1993 AD. Across the instrumental period, a good correlation is observed with the Baffin Bay and the Greenland Sea for B26 and B17 respectively, with both record showing minima corresponding to known Artic warming events such as the 1420 AD (for B17) and 1920–1940 (Early century warming, B17 & B26), together with a strong decline starting in the late 19th century. We simultaneously derived a chemical classification of sea ice-related contributors of ionic species (i.e. blowing snow, frost flowers, open water) utilizing the depletion of SO42− compare to Ca2+, K+ and Mg2+ characterizing sea ice brines and blowing snow as well the excess of Br− and Cl−, characterizing frost flowers, to elucidate the evolution of the different sources. In both B17 and B26 records we observe a strong contribution of blowing snow in the earliest part of the datasets, gradually declining in recent years in favour of open water sources.

scholarly journals Sea ice feedbacks influence the isotopic signature of Greenland ice sheet elevation changes: last interglacial HadCM3 simulations

2020 ◽  
Vol 16 (6) ◽  
pp. 2485-2508
Author(s):  
Irene Malmierca-Vallet ◽  
Louise C. Sime ◽  
Paul J. Valdes ◽  
Julia C. Tindall
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Lapse Rate ◽  
Last Interglacial ◽  
Elevation Change ◽  
Elevation Gradients ◽  
Lapse Rates

Abstract. Changes in the Greenland ice sheet (GIS) affect global sea level. Greenland stable water isotope (δ18O) records from ice cores offer information on past changes in the surface of the GIS. Here, we use the isotope-enabled Hadley Centre Coupled Model version 3 (HadCM3) climate model to simulate a set of last interglacial (LIG) idealised GIS surface elevation change scenarios focusing on GIS ice core sites. We investigate how δ18O depends on the magnitude and sign of GIS elevation change and evaluate how the response is altered by sea ice changes. We find that modifying GIS elevation induces changes in Northern Hemisphere atmospheric circulation, sea ice and precipitation patterns. These climate feedbacks lead to ice-core-averaged isotopic lapse rates of 0.49 ‰ (100 m)−1 for the lowered GIS states and 0.29 ‰ (100 m)−1 for the enlarged GIS states. This is lower than the spatially derived Greenland lapse rates of 0.62–0.72 ‰ (100 m)−1. These results thus suggest non-linearities in the isotope–elevation relationship and have consequences for the interpretation of past elevation and climate changes across Greenland. In particular, our results suggest that winter sea ice changes may significantly influence isotope–elevation gradients: winter sea ice effect can decrease (increase) modelled core-averaged isotopic lapse rate values by about −19 % (and +28 %) for the lowered (enlarged) GIS states, respectively. The largest influence of sea ice on δ18O changes is found in coastal regions like the Camp Century site.

scholarly journals Climate information preserved in seasonal water isotope at NEEM: relationships with temperature, circulation and sea ice

2018 ◽  
Vol 14 (7) ◽  
pp. 1067-1078 ◽  
Author(s):  
Minjie Zheng ◽  
Jesper Sjolte ◽  
Florian Adolphi ◽  
Bo Møllesøe Vinther ◽  
Hans Christian Steen-Larsen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Ice Cores ◽  
Principal Component ◽  
Satellite Observation ◽  
Climate Information ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
Baffin Bay ◽  
Core Data

Abstract. Analyzing seasonally resolved δ18O ice core data can aid the interpretation of the climate information in ice cores, also providing insights into factors governing the δ18O signal that cannot be deciphered by investigating the annual δ18O data only. However, the seasonal isotope signal has not yet been investigated in northern Greenland, e.g., at the NEEM (North Greenland Eemian Ice Drilling) ice core drill site. Here, we analyze seasonally resolved δ18O data from four shallow NEEM ice cores covering the last 150 years. Based on correlation analysis with observed temperature, we attribute about 70 and 30 % of annual accumulation to summer and winter, respectively. The NEEM summer δ18O signal correlates strongly with summer western Greenland coastal temperature and with the first principal component (PC1) of summer δ18O from multiple seasonally resolved ice cores from central/southern Greenland. However, there are no significant correlations between NEEM winter δ18O data and western Greenland coastal winter temperature or southern/central Greenland winter δ18O PC1. The stronger correlation with temperature during summer and the dominance of summer precipitation skew the annual δ18O signal in NEEM. The strong footprint of temperature in NEEM summer δ18O record also suggests that the summer δ18O record rather than the winter δ18O record is a better temperature proxy at the NEEM site. Despite the dominant signal of the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO) in the central–southern ice core data, both NAO and AMO exert weak influences on NEEM seasonal δ18O variations. The NEEM seasonal δ18O is found to be highly correlated with Baffin Bay sea ice concentration (SIC) in the satellite observation period (1979–2004), suggesting a connection of the sea ice extent with δ18O at NEEM. NEEM winter δ18O significantly correlates with SIC even for the period prior to satellite observation (1901–1978). The NEEM winter δ18O may reflect sea ice variations of Baffin Bay rather than temperature itself. This study shows that seasonally resolved δ18O records, especially for sites with a seasonal precipitation bias such as NEEM, provide a better understanding of how changing air temperature and circulation patterns are associated with the variability in the δ18O records.

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