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 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.

scholarly journals Coastal ice-core record of recent northwest Greenland temperature and sea-ice concentration

2015 ◽  
Vol 61 (230) ◽  
pp. 1137-1146 ◽  
Author(s):  
Erich C. Osterberg ◽  
Robert L. Hawley ◽  
Gifford Wong ◽  
Ben Kopec ◽  
David Ferris ◽  
...  
Keyword(s):  
Sea Ice ◽  
Regional Climate ◽  
Ice Core ◽  
Methanesulfonic Acid ◽  
Ice Cores ◽  
Snow Accumulation ◽  
Multilinear Regression ◽  
Sea Ice Concentration ◽  
Baffin Bay ◽  
Ice Concentration

AbstractCoastal ice cores provide an opportunity to investigate regional climate and sea-ice variability in the past to complement hemispheric-scale climate reconstructions from ice-sheet-interior ice cores. Here we describe robust proxies of Baffin Bay temperature and sea-ice concentration from the coastal 2Barrel ice core collected in the Thule region of northwest Greenland. Over the 1990–2010 record, 2Barrel annually averaged methanesulfonic acid (MSA) concentrations are significantly correlated with May–June Baffin Bay sea-ice concentrations and summer temperatures. Higher MSA is observed during warmer years with less sea ice, indicative of enhanced primary productivity in Baffin Bay. Similarly, 2Barrel annually averaged deuterium excess (d-excess) values are significantly correlated with annual Baffin Bay sea-ice concentrations and summer and annual temperatures. Warm (cool) years with anomalously low (high) sea-ice concentration are associated with proportionally more (less) low-d-excess Baffin Bay moisture at the ice-core site. Multilinear regression models incorporating 2Barrel MSA, d-excess and snow accumulation account for 38–51% of the Baffin Bay sea-ice and temperature variance. The annual temperature model is significantly correlated with temperatures throughout most of Greenland and eastern Arctic Canada due to the strong influence of the North Atlantic Oscillation and Atlantic Multidecadal Oscillation.

scholarly journals Interaction between Antarctic sea ice and synoptic activity in the circumpolar trough: implications for ice-core interpretation

2011 ◽  
Vol 52 (57) ◽  
pp. 9-17 ◽  
Author(s):  
Elisabeth Schlosser ◽  
Jordan G. Powers ◽  
Michael G. Duda ◽  
Kevin W. Manning
Keyword(s):  
Sea Ice ◽  
Meteorological Data ◽  
Ice Core ◽  
Ice Cores ◽  
Southern Annular Mode ◽  
Atmospheric Conditions ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Precipitation Seasonality

AbstractInteractions between Antarctic sea ice and synoptic activity in the circumpolar trough have been investigated using meteorological data from European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Re-analysis and sea-ice data from passive-microwave measurements. Total Antarctic sea-ice extent does not show large interannual variations. However, large differences are observed on a regional/monthly scale, depending on prevailing winds and currents, and thus on the prevailing synoptic situations. the sea-ice edge is also a preferred region for cyclogenesis due to the strong meridional temperature gradient (high baroclinicity) in that area. the motivation for this study was to gain a better understanding of the interaction between sea-ice extent and the general atmospheric flow, particularly the frequency of warm-air intrusions into the interior of the Antarctic continent, since this influences precipitation seasonality and must be taken into account for a correct climatic interpretation of ice cores. Two case studies of extraordinary sea-ice concentration anomalies in relation to the prevailing atmospheric conditions are presented. However, both strong positive and negative anomalies can be related to warm biases in ice cores (indicated by stable-isotope ratios), especially in connection with the negative phase of the Southern Annular Mode.

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 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 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 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.

A shift to predominant multi-year sea ice conditions in the Baffin Bay and North Atlantic Ocean during the Holocene-Glacial transition inferred from the EGRIP ice core

2021 ◽  
Author(s):  
Delia Segato ◽  
Francois Burgay ◽  
Niccolò Maffezzoli ◽  
Azzurra Spagnesi ◽  
Clara Turetta ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Sea Ice ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Ice Core ◽  
Ice Cores ◽  
Arctic Sea Ice ◽  
The Holocene ◽  
Baffin Bay ◽  
Ice Conditions

<p>Arctic sea ice has been melting at unprecedented rates in the past decades. Understanding past sea ice variability is of paramount importance to contextualize recent changes and constrain global climate models. Bromine enrichment (Br<sub>enr</sub>), relative to sea-water ratio, has been introduced as a proxy of first-year sea ice conditions within the ocean region influencing the ice core location (Spolaor et al., 2013). Br<sub>enr</sub> has been measured in ice cores from Greenland, that is the NEEM and RECAP cores. NEEM sea ice proxies are influenced by the region of the Canadian Arctic and Baffin Bay, while for the RECAP core it is mainly the North Atlantic Ocean. In this study we present the first high-resolution record of bromine enrichment from the EGRIP ice core in Greenland for the last 15.7 kyr BP, covering the Holocene-Glacial transition.</p><p>From preliminary back-trajectory analyses we suggest that EGRIP sea ice proxy sources are located in a wide region in the Baffin Bay and North Atlantic Ocean. We find EGRIP Br<sub>enr</sub> values of ~1 during cold periods, that is the Younger Dryas (12.9 – 11.7 kyr BP) and the last part of the Oldest Dryas (15.7 – 14.7 kyr BP), which we associate with predominant multi-year sea ice conditions. During warmer periods, instead, we observe higher Br<sub>enr</sub> values, ~3 for the Bølling-Allerød period (14.7 – 12.9 kyr BP) and progressively higher values from the early Holocene onwards, likely associated with an increased seasonal sea ice area. EGRIP Br<sub>enr</sub> is consistent with NEEM and RECAP records and it has the potential to extend our knowledge on Arctic past sea ice variability.</p><p><strong> </strong></p><p><strong>Bibliography</strong></p><p>Spolaor, A., Vallelonga, P., Plane, J. M. C., Kehrwald, N., Gabrieli, J., Varin, C., Turetta, C., Cozzi, G., Kumar, R., Boutron, C., and Barbante, C.: Halogen species record Antarctic sea ice extent over glacial–interglacial periods, Atmos. Chem. Phys., 13, 6623–6635, https://doi.org/10.5194/acp-13-6623-2013, 2013.</p>

scholarly journals Sea Ice Concentration and Sea Ice Extent Mapping with L-Band Microwave Radiometry and GNSS-R Data from the FFSCat Mission Using Neural Networks

2021 ◽  
Vol 13 (6) ◽  
pp. 1139
Author(s):  
David Llaveria ◽  
Juan Francesc Munoz-Martin ◽  
Christoph Herbert ◽  
Miriam Pablos ◽  
Hyuk Park ◽  
...  
Keyword(s):  
Sea Ice ◽  
Microwave Radiometer ◽  
Cost Effective ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
Neural Network Approach ◽  
Ice Concentration ◽  
L Band ◽  
Moderate Cost

CubeSat-based Earth Observation missions have emerged in recent times, achieving scientifically valuable data at a moderate cost. FSSCat is a two 6U CubeSats mission, winner of the ESA S3 challenge and overall winner of the 2017 Copernicus Masters Competition, that was launched in September 2020. The first satellite, 3Cat-5/A, carries the FMPL-2 instrument, an L-band microwave radiometer and a GNSS-Reflectometer. This work presents a neural network approach for retrieving sea ice concentration and sea ice extent maps on the Arctic and the Antarctic oceans using FMPL-2 data. The results from the first months of operations are presented and analyzed, and the quality of the retrieved maps is assessed by comparing them with other existing sea ice concentration maps. As compared to OSI SAF products, the overall accuracy for the sea ice extent maps is greater than 97% using MWR data, and up to 99% when using combined GNSS-R and MWR data. In the case of Sea ice concentration, the absolute errors are lower than 5%, with MWR and lower than 3% combining it with the GNSS-R. The total extent area computed using this methodology is close, with 2.5% difference, to those computed by other well consolidated algorithms, such as OSI SAF or NSIDC. The approach presented for estimating sea ice extent and concentration maps is a cost-effective alternative, and using a constellation of CubeSats, it can be further improved.

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