scholarly journals Optimal site selection for a high resolution ice core record in East Antarctica

2015 ◽  
Vol 11 (6) ◽  
pp. 5073-5111
Author(s):  
T. Vance ◽  
J. Roberts ◽  
A. Moy ◽  
M. Curran ◽  
C. Tozer ◽  
...  
Keyword(s):  
High Resolution ◽  
Site Selection ◽  
Ice Core ◽  
East Antarctica ◽  
Medium Range Weather Forecast ◽  
Climate Signal ◽  
Core Site ◽  
Ice Core Record ◽  
Selection For ◽  
A Site

Abstract. Ice cores provide some of the best dated and most comprehensive proxy records, as they yield a vast and growing array of proxy indicators. Selecting a site for ice core drilling is nonetheless challenging, as the assessment of potential new sites needs to consider a variety of factors. Here, we demonstrate a systematic approach to site selection for a new East Antarctic high resolution ice core record. Specifically, seven criteria are considered: (1) 2000 year old ice at 300 m depth, (2) above 1000 m elevation, (3) a minimum accumulation rate of 250 mm yr−1 IE, (4) minimal surface re-working to preserve the deposited climate signal, (5) a site with minimal displacement or elevation change of ice at 300 m depth, (6) a strong teleconnection to mid-latitude climate and (7) an appropriately complementary relationship to the existing Law Dome record (a high resolution record in East Antarctica). Once assessment of these physical characteristics identified promising regions, logistical considerations (for site access and ice core retrieval) were briefly considered. We use Antarctic surface mass balance syntheses, along with ground-truthing of satellite data by airborne radar surveys to produce all-of-Antarctica maps of surface roughness, age at specified depth, elevation and displacement change and surface air temperature correlations to pinpoint promising locations. We also use the European Centre for Medium-Range Weather Forecast ERA 20th Century reanalysis (ERA-20C) to ensure a site complementary to the Law Dome record is selected. We find three promising sites in the Indian Ocean sector of East Antarctica in the coastal zone from Enderby Land to the Ingrid Christensen Coast (50–100° E). Although we focus on East Antarctica for a new ice core site, the methodology is more generally applicable and we include key parameters for all of Antarctica which may be useful for ice core site selection elsewhere and/or for other purposes.

scholarly journals Optimal site selection for a high-resolution ice core record in East Antarctica

2016 ◽  
Vol 12 (3) ◽  
pp. 595-610 ◽  
Author(s):  
Tessa R. Vance ◽  
Jason L. Roberts ◽  
Andrew D. Moy ◽  
Mark A. J. Curran ◽  
Carly R. Tozer ◽  
...  
Keyword(s):  
High Resolution ◽  
Site Selection ◽  
Ice Core ◽  
East Antarctica ◽  
Medium Range Weather Forecast ◽  
Climate Signal ◽  
Core Site ◽  
Ice Core Record ◽  
Selection For ◽  
A Site

Abstract. Ice cores provide some of the best-dated and most comprehensive proxy records, as they yield a vast and growing array of proxy indicators. Selecting a site for ice core drilling is nonetheless challenging, as the assessment of potential new sites needs to consider a variety of factors. Here, we demonstrate a systematic approach to site selection for a new East Antarctic high-resolution ice core record. Specifically, seven criteria are considered: (1) 2000-year-old ice at 300 m depth; (2) above 1000 m elevation; (3) a minimum accumulation rate of 250 mm years−1 IE (ice equivalent); (4) minimal surface reworking to preserve the deposited climate signal; (5) a site with minimal displacement or elevation change in ice at 300 m depth; (6) a strong teleconnection to midlatitude climate; and (7) an appropriately complementary relationship to the existing Law Dome record (a high-resolution record in East Antarctica). Once assessment of these physical characteristics identified promising regions, logistical considerations (for site access and ice core retrieval) were briefly considered. We use Antarctic surface mass balance syntheses, along with ground-truthing of satellite data by airborne radar surveys to produce all-of-Antarctica maps of surface roughness, age at specified depth, elevation and displacement change, and surface air temperature correlations to pinpoint promising locations. We also use the European Centre for Medium-Range Weather Forecast ERA 20th Century reanalysis (ERA-20C) to ensure that a site complementary to the Law Dome record is selected. We find three promising sites in the Indian Ocean sector of East Antarctica in the coastal zone from Enderby Land to the Ingrid Christensen Coast (50–100° E). Although we focus on East Antarctica for a new ice core site, the methodology is more generally applicable, and we include key parameters for all of Antarctica which may be useful for ice core site selection elsewhere and/or for other purposes.

scholarly journals A 60-year ice-core record of regional climate from Adélie Land, coastal Antarctica

2017 ◽  
Vol 11 (1) ◽  
pp. 343-362 ◽  
Author(s):  
Sentia Goursaud ◽  
Valérie Masson-Delmotte ◽  
Vincent Favier ◽  
Susanne Preunkert ◽  
Michel Fily ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Interannual Variability ◽  
Ice Core ◽  
Ice Sheet ◽  
Sea Ice Extent ◽  
Antarctic Ice Sheet ◽  
Ice Core Record ◽  
Decadal Variations ◽  
The Mean

Abstract. A 22.4 m-long shallow firn core was extracted during the 2006/2007 field season from coastal Adélie Land. Annual layer counting based on subannual analyses of δ18O and major chemical components was combined with 5 reference years associated with nuclear tests and non-retreat of summer sea ice to build the initial ice-core chronology (1946–2006), stressing uncertain counting for 8 years. We focus here on the resulting δ18O and accumulation records. With an average value of 21.8 ± 6.9 cm w.e. yr−1, local accumulation shows multi-decadal variations peaking in the 1980s, but no long-term trend. Similar results are obtained for δ18O, also characterised by a remarkably low and variable amplitude of the seasonal cycle. The ice-core records are compared with regional records of temperature, stake area accumulation measurements and variations in sea-ice extent, and outputs from two models nudged to ERA (European Reanalysis) atmospheric reanalyses: the high-resolution atmospheric general circulation model (AGCM), including stable water isotopes ECHAM5-wiso (European Centre Hamburg model), and the regional atmospheric model Modèle Atmosphérique Régional (AR). A significant linear correlation is identified between decadal variations in δ18O and regional temperature. No significant relationship appears with regional sea-ice extent. A weak and significant correlation appears with Dumont d'Urville wind speed, increasing after 1979. The model-data comparison highlights the inadequacy of ECHAM5-wiso simulations prior to 1979, possibly due to the lack of data assimilation to constrain atmospheric reanalyses. Systematic biases are identified in the ECHAM5-wiso simulation, such as an overestimation of the mean accumulation rate and its interannual variability, a strong cold bias and an underestimation of the mean δ18O value and its interannual variability. As a result, relationships between simulated δ18O and temperature are weaker than observed. Such systematic precipitation and temperature biases are not displayed by MAR, suggesting that the model resolution plays a key role along the Antarctic ice sheet coastal topography. Interannual variations in ECHAM5-wiso temperature and precipitation accurately capture signals from meteorological data and stake observations and are used to refine the initial ice-core chronology within 2 years. After this adjustment, remarkable positive (negative) δ18O anomalies are identified in the ice-core record and the ECHAM5-wiso simulation in 1986 and 2002 (1998–1999), respectively. Despite uncertainties associated with post-deposition processes and signal-to-noise issues, in one single coastal ice-core record, we conclude that the S1C1 core can correctly capture major annual anomalies in δ18O as well as multi-decadal variations. These findings highlight the importance of improving the network of coastal high-resolution ice-core records, and stress the skills and limitations of atmospheric models for accumulation and δ18O in coastal Antarctic areas. This is particularly important for the overall East Antarctic ice sheet mass balance.

scholarly journals Location of a new ice core site at Talos Dome (East Antarctica)

2009 ◽  
Vol 49 (4-5) ◽  
Author(s):  
S. Urbini ◽  
L. Cafarella ◽  
A. Zirizzotti ◽  
C. Bianchi ◽  
I. Tabacco ◽  
...  
Keyword(s):  
Ice Core ◽  
East Antarctica ◽  
Core Site

scholarly journals The magnitude and impact of the 431 CE Tierra Blanca Joven eruption of Ilopango, El Salvador

2020 ◽  
Vol 117 (42) ◽  
pp. 26061-26068 ◽  
Author(s):  
Victoria C. Smith ◽  
Antonio Costa ◽  
Gerardo Aguirre-Díaz ◽  
Dario Pedrazzi ◽  
Andrea Scifo ◽  
...  
Keyword(s):  
High Resolution ◽  
El Salvador ◽  
Central America ◽  
State Of The Art ◽  
Ice Core ◽  
Ice Cores ◽  
Ash Layer ◽  
Ice Core Record ◽  
Climatic Impacts ◽  
Eruption Magnitude

The Tierra Blanca Joven (TBJ) eruption from Ilopango volcano deposited thick ash over much of El Salvador when it was inhabited by the Maya, and rendered all areas within at least 80 km of the volcano uninhabitable for years to decades after the eruption. Nonetheless, the more widespread environmental and climatic impacts of this large eruption are not well known because the eruption magnitude and date are not well constrained. In this multifaceted study we have resolved the date of the eruption to 431 ± 2 CE by identifying the ash layer in a well-dated, high-resolution Greenland ice-core record that is >7,000 km from Ilopango; and calculated that between 37 and 82 km3of magma was dispersed from an eruption coignimbrite column that rose to ∼45 km by modeling the deposit thickness using state-of-the-art tephra dispersal methods. Sulfate records from an array of ice cores suggest stratospheric injection of 14 ± 2 Tg S associated with the TBJ eruption, exceeding those of the historic eruption of Pinatubo in 1991. Based on these estimates it is likely that the TBJ eruption produced a cooling of around 0.5 °C for a few years after the eruption. The modeled dispersal and higher sulfate concentrations recorded in Antarctic ice cores imply that the cooling would have been more pronounced in the Southern Hemisphere. The new date confirms the eruption occurred within the Early Classic phase when Maya expanded across Central America.

scholarly journals A potential high-elevation ice-core site at Hielo Patagόnico Sur

2006 ◽  
Vol 43 ◽  
pp. 8-13 ◽  
Author(s):  
Margit Schwikowski ◽  
Sabina Brütsch ◽  
Gino Casassa ◽  
Andrés Rivera
Keyword(s):  
Wind Erosion ◽  
Ice Core ◽  
Ice Cores ◽  
High Elevation ◽  
The Core ◽  
Clear Sign ◽  
Southern Patagonia ◽  
Core Site ◽  
Ice Core Record ◽  
Good Potential

AbstractThe Patagonia icefields constitute a unique location in the Southern Hemisphere for obtaining non-polar paleo-records from ice cores south of 45°S. Nevertheless, no ice-core record with meaningful paleoclimate information has yet been obtained from Patagonia. This deficiency is due to extremely harsh field conditions, and to the fact that the main plateaus of both Hielo Patagónico Norte (HPN; northern Patagonia icefield) and Hielo Patagónico Sur (HPS; southern Patagonia icefield) are strongly affected by meltwater percolation. In order to explore the suitability of high-elevation glacier sites at HPS as paleoclimate archives, three shallow firn cores were retrieved covering the altitude range 1543−2300 ma.s.l. The glaciochemical records from the two lower sites confirm the presence of superimposed ice, a clear sign of meltwater formation and percolation. In the core from 2300 m, the glaciochemical signature appears to be preserved, indicating that no significant melting occurred. Although there might be problems associated with wind erosion and extreme melt events, there is good potential for well-preserved paleo-records within glaciers in the Patagonia icefields located higher than 2300 m.

Post-depositional processes visible in the integration of EGRIP high-resolution water isotope record and visual stratigraphy

2021 ◽  
Author(s):  
Valerie Morris ◽  
Julien Westhoff ◽  
Bruce Vaughn ◽  
Ilka Weikusat ◽  
Tyler Jones ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Cores ◽  
Strong Relationship ◽  
Dark Field ◽  
Scanning System ◽  
Climate Signal ◽  
Depositional Processes ◽  
Isotope Record ◽  
Water Isotope

<p>With recent advances in analytical techniques, water stable isotope ratios can be measured in astounding detail in ice core records (~mm scale or equivalent to subannual resolution). While this has enabled the study of past climates across a vast range of timescales, the full set of processes driving the highest frequency variability in these water isotope records remains poorly understood. In the EastGRIP ice core, we observe a strong relationship between high-frequency water isotope anomalies (sharp transitions on the scale of cms) and variability in the visual stratigraphy of the ice. The water isotope timeseries reveals these anomalies that would otherwise be missed using traditional lower resolution discrete sampling methods (5-50 cm scale).  A comparison with the dark-field imaging of stratigraphic layers (high-resolution line-scanning system; 50µm/pix) from the EGRIP ice core indicates a correlation between bubble-free ice layers and the sharp transitions observed in the isotope record.  Prior to this comparison, such anomalies in high-resolution isotope records were often dismissed as analytical artifacts. The striking correspondence to the bubble-free ice layers, which is a parameter measured independently from the isotopes, suggests the isotope variability is real. We are investigating a range of depositional and post-depositional processes that may may be able to explain the origin of this variability and its relationship to the physical properties of the ice. This study has implications for frequency analysis of the isotope data, and the related analysis of isotope diffusion and its effects on the recorded climate signal. Understanding these anomalies opens new doors to the interpretation of climate signals in ice cores.</p>

Continuous (CFA) CH4 record of the Elbrus ice core, Caucasus (preliminary results)

2020 ◽  
Author(s):  
Diana Vladimirova ◽  
Xavier Faïn ◽  
Patrick Ginot ◽  
Stanislav Kutuzov ◽  
Vladimir Mikhalenko
Keyword(s):  
High Resolution ◽  
Optical Feedback ◽  
Ice Core ◽  
Flow Analysis ◽  
Preliminary Results ◽  
Mixing Ratios ◽  
Enhanced Absorption ◽  
Ice Core Record ◽  
In Situ Production

<p>Methane (CH<sub>4</sub>) is the third most powerful greenhouse gas. However, its warming potential is two orders of magnitude higher than of carbon dioxide and its residence time in the atmosphere is only 9.1 ± 0.9 years. It makes CH<sub>4</sub> a good indicator of rapid climate variations both under natural conditions and due to the anthropogenic influence.</p><p>The Elbrus ice core was drilled in 2009 on the Western Plato (43°20’53.9’’N, 42°25’36.0’’E) at elevation 5115 m a.s.l. It is 182 m long and is dated back to 280 ± 400 CE (Common Era). The CH<sub>4</sub> mixing ratios were analyzed using a continuous flow analysis (CFA) system paired with optical-feedback cavity-enhanced absorption spectroscopy. The measurements campaign was organized at Institut des Géosciences de l'Environnement (IGE), Grenoble, France. This is a first high-resolution mid-latitude CH<sub>4</sub> record. The record aims to better constrain the past evolution of mid-latitude methane sources.</p><p>Here we present preliminary results of the methane concentration measurements of the Elbrus ice core in high-resolution (CFA CH<sub>4</sub> record). We observe in situ production (max level 2900 ppb) and a baseline. We inspect a potential origin of the multiple spikes in the high-resolution record. Supposedly, either an in-situ production in the dust-rich layers occurred or a gas dissolution in the melt layers took place. However, the possibility of in-situ production during continuous gas extraction has to be further studied. The identified melt layers can serve as an indicator of interrupted stable water isotopic signal and may be supportive in the regional temperature reconstructions based on the Elbrus ice core record. A cleaned off the spikes record is inspected for the natural variability of the CH<sub>4</sub> baseline concentration related to the short-term climate and methane emissions variability.</p>

scholarly journals High-resolution Holocene N2O ice core record and its relationship with CH4and CO2

2002 ◽  
Vol 16 (1) ◽  
pp. 10-1-10-8 ◽  
Author(s):  
Jacqueline Flückiger ◽  
Eric Monnin ◽  
Bernhard Stauffer ◽  
Jakob Schwander ◽  
Thomas F. Stocker ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Core Record
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