scholarly journals Sources and transport of dust to East Antarctica: new insights from high-resolution terrestrial and marine aerosol records from the Talos Dome ice core

2013 ◽  
Vol 9 (3) ◽  
pp. 3321-3370 ◽  
Author(s):  
S. Schüpbach ◽  
U. Federer ◽  
S. Albani ◽  
C. Barbante ◽  
T. F. Stocker ◽  
...  
Keyword(s):  
Ross Sea ◽  
Transport Model ◽  
Ice Core ◽  
Ice Cores ◽  
Sea Salt ◽  
Climate Variations ◽  
Last Interglacial ◽  
The Holocene ◽  
Sea Area ◽  
The Last Glacial

Abstract. In this study we report on new non-sea salt calcium (nssCa2+, mineral dust proxy) and sea salt sodium (ssNa+, sea ice proxy) records along the East Antarctic Talos Dome deep ice core in centennial resolution reaching back 150 thousand years before present. During glacial conditions nssCa2+ fluxes in Talos Dome are strongly related to temperature as has been observed before in other deep Antarctic ice core records, and has been associated with synchronous changes in the main source region (southern South America) during climate variations in the last glacial. However, during warmer climate conditions Talos Dome mineral dust input is clearly elevated compared to other records mainly due to the contribution of additional local dust sources in the Ross Sea area. Based on a simple transport model we compare nssCa2+ fluxes of different East Antarctic ice cores. From this multi-site comparison we conclude that changes in transport efficiency or atmospheric lifetime of dust particles do have a minor effect compared to source strength changes on the large scale concentration changes observed in Antarctic ice cores during climate variations of the past 150 thousand years. Our transport model applied on ice core data only so far is further validated by climate model data. The availability of multiple East Antarctic nssCa2+ records allows for a revision of a former estimate on the atmospheric CO2 sensitivity to reduced dust induced iron fertilisation in the Southern Ocean (SO) during the transition from the Last Glacial Maximum to the Holocene (T1). While the former estimate based on the EDC record only suggested 20 ppm, we find reduced dust induced iron fertilisation in the SO to be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1. During the last interglacial, ssNa+ levels of EDC and EDML are only half of the Holocene levels, in line with higher temperatures during that period, indicating much reduced sea ice extent in the Atlantic as well as the Indian Ocean sector of the SO. In contrast, Holocene ssNa+ flux in Talos Dome is about the same as during the last interglacial, indicating that there was similar ice cover present in the Ross Sea area during MIS 5.5 as during the Holocene.

scholarly journals High-resolution mineral dust and sea ice proxy records from the Talos Dome ice core

2013 ◽  
Vol 9 (6) ◽  
pp. 2789-2807 ◽  
Author(s):  
S. Schüpbach ◽  
U. Federer ◽  
P. R. Kaufmann ◽  
S. Albani ◽  
C. Barbante ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Transport Model ◽  
Mineral Dust ◽  
Ice Core ◽  
Ice Cores ◽  
Last Interglacial ◽  
The Holocene ◽  
Proxy Records

Abstract. In this study we report on new non-sea salt calcium (nssCa2+, mineral dust proxy) and sea salt sodium (ssNa+, sea ice proxy) records along the East Antarctic Talos Dome deep ice core in centennial resolution reaching back 150 thousand years (ka) before present. During glacial conditions nssCa2+ fluxes in Talos Dome are strongly related to temperature as has been observed before in other deep Antarctic ice core records, and has been associated with synchronous changes in the main source region (southern South America) during climate variations in the last glacial. However, during warmer climate conditions Talos Dome mineral dust input is clearly elevated compared to other records mainly due to the contribution of additional local dust sources in the Ross Sea area. Based on a simple transport model, we compare nssCa2+ fluxes of different East Antarctic ice cores. From this multi-site comparison we conclude that changes in transport efficiency or atmospheric lifetime of dust particles do have a minor effect compared to source strength changes on the large-scale concentration changes observed in Antarctic ice cores during climate variations of the past 150 ka. Our transport model applied on ice core data is further validated by climate model data. The availability of multiple East Antarctic nssCa2+ records also allows for a revision of a former estimate on the atmospheric CO2 sensitivity to reduced dust induced iron fertilisation in the Southern Ocean during the transition from the Last Glacial Maximum to the Holocene (T1). While a former estimate based on the EPICA Dome C (EDC) record only suggested 20 ppm, we find that reduced dust induced iron fertilisation in the Southern Ocean may be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1. During the last interglacial, ssNa+ levels of EDC and EPICA Dronning Maud Land (EDML) are only half of the Holocene levels, in line with higher temperatures during that period, indicating much reduced sea ice extent in the Atlantic as well as the Indian Ocean sector of the Southern Ocean. In contrast, Holocene ssNa+ flux in Talos Dome is about the same as during the last interglacial, indicating that there was similar ice cover present in the Ross Sea area during MIS 5.5 as during the Holocene.

scholarly journals Sea ice as a source of sea salt aerosol to Greenland ice cores: a model-based study

2017 ◽  
Vol 17 (15) ◽  
pp. 9417-9433 ◽  
Author(s):  
Rachael H. Rhodes ◽  
Xin Yang ◽  
Eric W. Wolff ◽  
Joseph R. McConnell ◽  
Markus M. Frey
Keyword(s):  
Sea Ice ◽  
Atmospheric Chemistry ◽  
Transport Model ◽  
Ice Core ◽  
Ice Cores ◽  
Open Ocean ◽  
Sea Salt ◽  
The Arctic ◽  
Sea Salt Aerosol ◽  
Annual Variability

Abstract. Growing evidence suggests that the sea ice surface is an important source of sea salt aerosol and this has significant implications for polar climate and atmospheric chemistry. It also suggests the potential to use ice core sea salt records as proxies for past sea ice extent. To explore this possibility in the Arctic region, we use a chemical transport model to track the emission, transport, and deposition of sea salt from both the open ocean and the sea ice, allowing us to assess the relative importance of each. Our results confirm the importance of sea ice sea salt (SISS) to the winter Arctic aerosol burden. For the first time, we explicitly simulate the sea salt concentrations of Greenland snow, achieving values within a factor of two of Greenland ice core records. Our simulations suggest that SISS contributes to the winter maxima in sea salt characteristic of ice cores across Greenland. However, a north–south gradient in the contribution of SISS relative to open-ocean sea salt (OOSS) exists across Greenland, with 50 % of winter sea salt being SISS at northern sites such as NEEM (77° N), while only 10 % of winter sea salt is SISS at southern locations such as ACT10C (66° N). Our model shows some skill at reproducing the inter-annual variability in sea salt concentrations for 1991–1999, particularly at Summit where up to 62 % of the variability is explained. Future work will involve constraining what is driving this inter-annual variability and operating the model under different palaeoclimatic conditions.

scholarly journals A 1400-Year Oxygen Isotope History from the Ross Sea Area, Antarctica

1990 ◽  
Vol 14 ◽  
pp. 94-98 ◽  
Author(s):  
P.M. Grootes ◽  
M. Stuiver ◽  
T.L. Saling ◽  
P.A. Mayewski ◽  
M.J. Spencer ◽  
...  
Keyword(s):  
Ross Sea ◽  
Regional Climate ◽  
Ice Core ◽  
Ice Cores ◽  
Local Conditions ◽  
Climate Fluctuations ◽  
Ross Ice Shelf ◽  
Isotope Record ◽  
Highly Correlated ◽  
Sea Area

Four ice cores from the Ross Sea drainage, Antarctica, show patterns of δ18O variations on a time scale of decades to centuries over the last 1400 years without change in the long-term average δ18O. Century scale δ18O fluctuations in the two cores drilled in the Ross Ice Shelf at Station J-9 (82°23′S, 168°38′W, elevation 60 m) are highly correlated (P < 2 × 10−4). The long isotope record (>30 000 a) of the 1978 J-9 core thus represents local conditions over at least 102 m and on time scales of 100 years and longer.Regional correlations between the J-9 δ18O records and those from Ridge BC (82°54′S, 136°40′W, elevation 509 m) and the Dominion Range (85°15′S, 166°10′E, elevation 2700 m) are barely significant (P ≈ 0.05 for J-9 '76 and Dominion Range, 580 to 1400 years ago) or absent. The failure to find clear regional isotope trends related to climate fluctuations may reflect the finding that between 1957 and 1982 the area was in the transition zone between areas with opposite temperature trends, and showed little or no temperature change. The fact that the records nevertheless show significant δ18O fluctuations highlights the need to base regional climate reconstructions on a regional suite of ice-core records.

scholarly journals Sea ice as a source of sea salt aerosol to Greenland ice cores: a model-based study

2017 ◽  
Author(s):  
Rachael H. Rhodes ◽  
Xin Yang ◽  
Eric W. Wolff ◽  
Joseph R. McConnell ◽  
Markus M. Frey
Keyword(s):  
Sea Ice ◽  
Atmospheric Chemistry ◽  
Transport Model ◽  
Ice Core ◽  
Ice Cores ◽  
Open Ocean ◽  
Sea Salt ◽  
The Arctic ◽  
Sea Salt Aerosol ◽  
Annual Variability

Abstract. Growing evidence suggests that the sea ice surface is an important source of sea salt aerosol and this has significant implications for polar climate and atmospheric chemistry. It also offers the opportunity to use ice core sea salt records as proxies for past sea ice extent. To explore this possibility in the Arctic region, we use a chemical transport model to track the emission, transport and deposition of sea salt from both the open ocean and the sea ice, allowing us to assess the relative importance of each. Our results confirm the importance of sea ice sea salt (SISS) to the winter Arctic aerosol burden. For the first time, we explicitly simulate the sea salt concentrations of Greenland snow and find they match high resolution Greenland ice core records to within a factor of two. Our simulations suggest that SISS contributes to the winter maxima in sea salt characteristic of ice cores across Greenland. A north-south gradient in the contribution of SISS relative to open ocean sea salt (OOSS) exists across Greenland, with 50 % of sea salt being SISS at northern sites such as NEEM, while only 10 % of sea salt is SISS at southern locations such as ACT10C. Our model shows some skill at reproducing the inter-annual variability in sea salt concentrations for 1991–1999 AD, particularly at Summit where up to 62 % of the variability is explained. Future work will involve constraining what is driving this inter-annual variability and operating the model under different paleoclimatic conditions.

scholarly journals NALPS: a precisely dated European climate record 120–60 ka

2011 ◽  
Vol 7 (2) ◽  
pp. 1049-1072 ◽  
Author(s):  
R. Boch ◽  
H. Cheng ◽  
C. Spötl ◽  
R. L. Edwards ◽  
X. Wang ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Core ◽  
Ice Cores ◽  
Climate Variations ◽  
Climate Record ◽  
Last Glacial ◽  
European Climate ◽  
Stable Isotopic ◽  
The Alps ◽  
The Last Glacial

Abstract. Accurate and precise chronologies are essential in understanding the rapid and recurrent climate variations of the Last Glacial – known as Dansgaard-Oeschger (D-O) events – found in the Greenland ice cores and other climate archives. The existing chronological uncertainties during the Last Glacial, however, are still large. Radiometric age data and stable isotopic signals from speleothems are promising to improve the absolute chronology. We present a record of several precisely dated stalagmites from caves located at the northern rim of the Alps (NALPS), a region that favours comparison with the climate in Greenland. The record covers most of the interval from 120 to 60 ka at an average temporal resolution of 2 to 22 a and 2 σ-age uncertainties of ca. 200 to 500 a. The rapid and large oxygen isotope shifts of 1 to 4.5‰ occurred within decades to centuries and strongly mimic the Greenland D-O pattern. Compared to the current Greenland ice-core timescale the NALPS record suggests overall younger ages of rapid warming and cooling transitions between 120 to 60 ka. In particular, there is a discrepancy in the duration of stadial 22 between the ice-core and the stalagmite chronology (ca. 3000 vs. 3650 a). The short-lived D-O events 18 and 18.1 are not recorded in NALPS, provoking questions with regard to the nature and the regional expression of these events. NALPS resolves recurrent short-lived climate changes within the cold Greenland stadial (GS) and warm interstadial (GI) successions, i.e. abrupt warming events preceding GI 21 and 23 (precursor-type events) and at the end of GI 21 and 25 (rebound-type events), as well as intermittent cooling events during GI 22 and 24. Such superimposed Last Glacial events have not been documented in Europe before.

Offsets among ice core derived CO2 reconstructions covering the Holocene and Last Interglacial

2020 ◽  
Author(s):  
Christoph Nehrbass-Ahles ◽  
Jochen Schmitt ◽  
Bernhard Bereiter ◽  
Sarah Eggleston ◽  
Lars Mächler ◽  
...  
Keyword(s):  
Atmospheric Carbon Dioxide ◽  
Ice Core ◽  
Ice Cores ◽  
Last Interglacial ◽  
High Accumulation ◽  
The Holocene ◽  
Drilling Site ◽  
Common Signal ◽  
Unambiguous Detection

&lt;p&gt;There is a general consensus in the scientific community that Greenlandic ice cores do not allow for reconstruction of past atmospheric carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) concentrations due to artifacts likely caused by &lt;em&gt;in-situ&lt;/em&gt; production of excess CO&lt;sub&gt;2&lt;/sub&gt; from both organic and inorganic carbon compounds within the ice archive. In the case of Antarctic ice cores such processes are thought to be insignificant, making Antarctic ice cores the only direct archive of past atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentrations beyond modern observations. However, with increasing numbers of high-precision CO&lt;sub&gt;2&lt;/sub&gt; reconstructions from multiple Antarctic ice cores &amp;#8211; mostly covering specific time intervals during the last 130 ka &amp;#8211; it has become evident that offsets in CO&lt;sub&gt;2&lt;/sub&gt; are not unique to Greenland ice cores. Over the last decade evidence is mounting that small systematic offsets of typically 2-10 ppm exist among different Antarctic CO&lt;sub&gt;2&lt;/sub&gt; records covering the same time period. Because CO&lt;sub&gt;2&lt;/sub&gt; is well-mixed within the atmosphere different ice cores should agree with each other within their measurement uncertainty, independent of the ice core drilling site. The unambiguous detection of such offsets between different ice cores is only possible in the absence of strong atmospheric trends, such as during interglacial periods. Here, we take a closer look at CO&lt;sub&gt;2&lt;/sub&gt; offsets among records available for the Holocene and the Last Interglacial and investigate their long-term evolution. We present unpublished CO&lt;sub&gt;2&lt;/sub&gt; data from multiple ice cores, including Talos Dome and EPICA Dome C, and discuss possible offset producing mechanisms. We speculate that Antarctic ice cores are also subject to slowly progressing &lt;em&gt;in-situ&lt;/em&gt; production of CO&lt;sub&gt;2&lt;/sub&gt; over many millennia, similar to Greenlandic ice cores, however to a much smaller extent and limited to about 10 ppm. We further note a tendency for higher offsets in the case of high accumulation sites. Despite all possible mechanisms that have the potential to alter CO&lt;sub&gt;2&lt;/sub&gt; concentrations within the ice archive, we highlight that the overall integrity of the ice core-based CO&lt;sub&gt;2&lt;/sub&gt; reconstruction is not in question, as all records generally share the same common signal. However, the absolute CO&lt;sub&gt;2&lt;/sub&gt; levels should be interpreted with care and in light of such potential offsets.&lt;/p&gt;

scholarly journals A 1400-Year Oxygen Isotope History from the Ross Sea Area, Antarctica

1990 ◽  
Vol 14 ◽  
pp. 94-98 ◽  
Author(s):  
P.M. Grootes ◽  
M. Stuiver ◽  
T.L. Saling ◽  
P.A. Mayewski ◽  
M.J. Spencer ◽  
...  
Keyword(s):  
Ross Sea ◽  
Regional Climate ◽  
Ice Core ◽  
Ice Cores ◽  
Local Conditions ◽  
Climate Fluctuations ◽  
Ross Ice Shelf ◽  
Isotope Record ◽  
Highly Correlated ◽  
Sea Area

Four ice cores from the Ross Sea drainage, Antarctica, show patterns of δ18O variations on a time scale of decades to centuries over the last 1400 years without change in the long-term average δ18O. Century scale δ18O fluctuations in the two cores drilled in the Ross Ice Shelf at Station J-9 (82°23′S, 168°38′W, elevation 60 m) are highly correlated (P &lt; 2 × 10−4). The long isotope record (&gt;30 000 a) of the 1978 J-9 core thus represents local conditions over at least 102 m and on time scales of 100 years and longer. Regional correlations between the J-9 δ18O records and those from Ridge BC (82°54′S, 136°40′W, elevation 509 m) and the Dominion Range (85°15′S, 166°10′E, elevation 2700 m) are barely significant (P ≈ 0.05 for J-9 '76 and Dominion Range, 580 to 1400 years ago) or absent. The failure to find clear regional isotope trends related to climate fluctuations may reflect the finding that between 1957 and 1982 the area was in the transition zone between areas with opposite temperature trends, and showed little or no temperature change. The fact that the records nevertheless show significant δ18O fluctuations highlights the need to base regional climate reconstructions on a regional suite of ice-core records.

scholarly journals Soluble Impurities in Four Antarctic Ice Cores Over the Last 30 000 Years

1988 ◽  
Vol 10 ◽  
pp. 116-120 ◽  
Author(s):  
Michel R. Legrand ◽  
Robert J. Delmas
Keyword(s):  
Atmospheric Chemistry ◽  
Major Ions ◽  
Ice Core ◽  
Ice Cores ◽  
Sea Salt ◽  
The Past ◽  
Study Sites ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The chemical composition of soluble impurities along the Dome C ice core covering approximately the last 30 000 years is reported and interpreted in terms of atmospheric contributions. Terrestrial and sea-salt inputs are known to have been much higher during the Last Glacial Maximum (LGM) than during the Holocene period. For this reason, the gas-derived compounds (mainly H2SO4 and HNO3) which dominate the chemistry of present-day snow are minor components in LGM snow. The exact calculation of each of the various contributions has been made possible by the determination of all major ions (H+, Na+, K+, NH4 +, Mg2+, Ca2+, NO3 −, SO4 2− and Cl−) in the samples. Three additional deep ice cores from other Antarctic areas have also been analyzed, but in a less comprehensive manner than the Dome C core. The differences observed at the four study sites increase the general understanding of the past atmospheric chemistry of the Southern Hemisphere.

scholarly journals NALPS: a precisely dated European climate record 120–60 ka

2011 ◽  
Vol 7 (4) ◽  
pp. 1247-1259 ◽  
Author(s):  
R. Boch ◽  
H. Cheng ◽  
C. Spötl ◽  
R. L. Edwards ◽  
X. Wang ◽  
...  
Keyword(s):  
Climate Changes ◽  
Ice Core ◽  
Ice Cores ◽  
Climate Variations ◽  
Climate Record ◽  
Last Glacial ◽  
European Climate ◽  
Stable Isotopic ◽  
The Alps ◽  
The Last Glacial

Abstract. Accurate and precise chronologies are essential in understanding the rapid and recurrent climate variations of the Last Glacial – known as Dansgaard-Oeschger (D-O) events – found in the Greenland ice cores and other climate archives. The existing chronological uncertainties during the Last Glacial, however, are still large. Radiometric age data and stable isotopic signals from speleothems are promising to improve the absolute chronology. We present a record of several precisely dated stalagmites from caves located at the northern rim of the Alps (NALPS), a region that favours comparison with the climate in Greenland. The record covers most of the interval from 120 to 60 ka at an average temporal resolution of 2 to 22 yr and 2σ-age uncertainties of ca. 200 to 500 yr. The rapid and large oxygen isotope shifts of 1 to 4.5‰ occurred within decades to centuries and strongly mimic the Greenland D-O pattern. Compared to the updated Greenland ice-core timescale (GICC05modelext) the NALPS record confirms the timing of rapid warming and cooling transitions between 118 and 106 ka, but suggests younger ages for D-O events between 106 and 60 ka. As an exception, the timing of the rapid transitions into and out of the stadial following GI 22 is earlier in NALPS than in the Greenland ice-core timescale. In addition, there is a discrepancy in the duration of this stadial between the ice-core and the stalagmite chronology (ca. 2900 vs. 3650 yr). The short-lived D-O events 18 and 18.1 are not recorded in NALPS, provoking questions with regard to the nature and the regional expression of these events. NALPS resolves recurrent short-lived climate changes within the cold Greenland stadial and warm interstadial successions, i.e. abrupt warming events preceding GI 21 and 23 (precursor-type events) and at the end of GI 21 and 25 (rebound-type events), as well as intermittent cooling events during GI 22 and 24. Such superimposed events have not yet been documented outside Greenland.

scholarly journals Pronounced summer warming in northwest Greenland during the Holocene and Last Interglacial

2018 ◽  
Vol 115 (25) ◽  
pp. 6357-6362 ◽  
Author(s):  
Jamie M. McFarlin ◽  
Yarrow Axford ◽  
Magdalena R. Osburn ◽  
Meredith A. Kelly ◽  
Erich C. Osterberg ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Last Interglacial ◽  
Last Glacial Period ◽  
The Holocene ◽  
Sedimentary Records ◽  
Paleoclimate Records ◽  
The Last Glacial

Projections of future rates of mass loss from the Greenland Ice Sheet are highly uncertain because its sensitivity to warming is unclear. Geologic reconstructions of Quaternary interglacials can illustrate how the ice sheet responded during past warm periods, providing insights into ice sheet behavior and important tests for data-model comparisons. However, paleoclimate records from Greenland are limited: Early Holocene peak warmth has been quantified at only a few sites, and terrestrial sedimentary records of prior interglacials are exceptionally rare due to glacial erosion during the last glacial period. Here, we discuss findings from a lacustrine archive that records both the Holocene and the Last Interglacial (LIG) from Greenland, allowing for direct comparison between two interglacials. Sedimentary chironomid assemblages indicate peak July temperatures 4.0 to 7.0 °C warmer than modern during the Early Holocene maximum in summer insolation. Chaoborus and chironomids in LIG sediments indicate July temperatures at least 5.5 to 8.5 °C warmer than modern. These estimates indicate pronounced warming in northwest Greenland during both interglacials. This helps explain dramatic ice sheet thinning at Camp Century in northwest Greenland during the Early Holocene and, for the LIG, aligns with controversial estimates of Eemian warming from ice core data retrieved in northern Greenland. Converging geologic evidence for strong LIG warming is challenging to reconcile with inferred Greenland Ice Sheet extent during the LIG, and the two appear incompatible in many models of ice sheet evolution. An increase in LIG snowfall could help resolve this problem, pointing to the need for hydroclimate reconstructions from the region.

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