scholarly journals Eclipse Ice Core Accumulation and Stable Isotope Variability as an Indicator of North Pacific Climate

2012 ◽  
Vol 25 (18) ◽  
pp. 6426-6440 ◽  
Author(s):  
Eric P. Kelsey ◽  
Cameron P. Wake ◽  
Kaplan Yalcin ◽  
Karl Kreutz
Keyword(s):  
Stable Isotope ◽  
North Pacific ◽  
Geopotential Height ◽  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Cold Season ◽  
High Accumulation ◽  
The North ◽  
The Individual

Abstract The high accumulation rate and negligible amount of melt at Eclipse Icefield (3017 m) in the Saint Elias Range of Yukon, Canada, allows for the preservation of a high-resolution isotopic and glaciochemical records valuable for reconstruction of climatic variables. Each of the three Eclipse ice cores have a well-constrained depth–age scale with dozens of reference horizons over the twentieth century that permits an exceptional level of confidence in the results of the current calibration exercise. Stacked time series of accumulation and stable isotopes were divided into cold and warm seasons and seasons of extreme high and extreme low accumulation and stable isotope values (eight groups). For each group, season-averaged composites of 500-hPa geopotential height grids, and the individual seasons that constitute them, were analyzed to elucidate common anomalous flow patterns. This analysis shows that the most fractionated isotopes and lowest accumulation cold seasons reflect a more zonal height pattern in the North Pacific associated with negative Pacific–North American (PNA) and Pacific decadal oscillation (PDO) indices. Conversely, the least fractionated isotopes and highest accumulation cold seasons are associated with a positive PNA pattern. Although only a maximum of approximately 20% of the total number of accumulation and stable isotope seasons exhibit a relatively consistent relationship with 500-hPa geopotential height patterns, these results support the hypothesis that the most extreme accumulation and extreme isotope cold-season values in the Saint Elias Mountains are related to consistent atmospheric circulation and oceanic sea surface temperature patterns.

scholarly journals Air Content Of The Byrd Core And Past Changes In The West Antarctic Ice Sheet

1982 ◽  
Vol 3 ◽  
pp. 269-273 ◽  
Author(s):  
D. Raynaud ◽  
I. M. Whillans
Keyword(s):  
Stable Isotope ◽  
Accumulation Rate ◽  
Ice Core ◽  
Ice Sheet ◽  
Ice Cores ◽  
Isotope Ratios ◽  
Ice Age ◽  
Gas Content ◽  
Stable Isotope Ratios ◽  
Antarctic Ice Sheet

Analyses of ice cores taken from the Antarctic ice sheet can provide information on the environmental conditions under which the ice was formed. New results from measurements of gas content and stable isotope ratios in the Byrd station ice core are discussed and interpreted in terms of past iceflow changes.165 selected ice samples from 32 different depth levels along the core were processed for total gas content V and stable isotope ratios. This large dataset is used to discuss the variability and significance of the values of V at different depths. The short term variations of V are mainly explained by heterogeneities of the pore volume when the firn pores close off.The general trends in the values of V with depth are then used to investigate the possibility of past changes in the ice sheet. They suggest near-steady flow during the past few tens of thousands of years and that a thickening of about 200 to 250 m occurred in this area of the ice sheet at the end of the last ice age. This thickening could be due to a change in the accumulation rate.

scholarly journals Volcanic Fluxes Over the Last Millennium as Recorded in the Gv7 Ice Core (Northern Victoria Land, Antarctica)

Geosciences ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 38 ◽  
Author(s):  
Raffaello Nardin ◽  
Alessandra Amore ◽  
Silvia Becagli ◽  
Laura Caiazzo ◽  
Massimo Frezzotti ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Deposition Flux ◽  
Last Millennium ◽  
Regional Variability ◽  
High Accumulation ◽  
Continental Scale ◽  
Victoria Land

Major explosive volcanic eruptions may significantly alter the global atmosphere for about 2–3 years. During that period, volcanic products (mainly H2SO4) with high residence time, stored in the stratosphere or, for shorter times, in the troposphere are gradually deposited onto polar ice caps. Antarctic snow may thus record acidic signals providing a history of past volcanic events. The high resolution sulphate concentration profile along a 197 m long ice core drilled at GV7 (Northern Victoria land) was obtained by Ion Chromatography on around 3500 discrete samples. The relatively high accumulation rate (241 ± 13 mm we yr −1) and the 5-cm sampling resolution allowed a preliminary counted age scale. The obtained stratigraphy covers roughly the last millennium and 24 major volcanic eruptions were identified, dated, and tentatively ascribed to a source volcano. The deposition flux of volcanic sulphate was calculated for each signature and the results were compared with data from other Antarctic ice cores at regional and continental scale. Our results show that the regional variability is of the same order of magnitude as the continental one.

scholarly journals A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core

2013 ◽  
Vol 9 (6) ◽  
pp. 2713-2730 ◽  
Author(s):  
S. O. Rasmussen ◽  
P. M. Abbott ◽  
T. Blunier ◽  
A. J. Bourne ◽  
E. Brook ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Conductivity Measurement ◽  
Ice Cores ◽  
Heat Diffusion ◽  
Ice Age ◽  
Age Difference ◽  
Volcanic Origin ◽  
The North ◽  
North Greenland

Abstract. A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05) and its model extension (GICC05modelext) from the NGRIP core to the NEEM core using 787 match points of mainly volcanic origin identified in the electrical conductivity measurement (ECM) and dielectrical profiling (DEP) records. Tephra horizons found in both the NEEM and NGRIP ice cores are used to test the matching based on ECM and DEP and provide five additional horizons used for the timescale transfer. A thinning function reflecting the accumulated strain along the core has been determined using a Dansgaard–Johnsen flow model and an isotope-dependent accumulation rate parameterization. Flow parameters are determined from Monte Carlo analysis constrained by the observed depth-age horizons. In order to construct a chronology for the gas phase, the ice age–gas age difference (Δage) has been reconstructed using a coupled firn densification-heat diffusion model. Temperature and accumulation inputs to the Δage model, initially derived from the water isotope proxies, have been adjusted to optimize the fit to timing constraints from δ15N of nitrogen and high-resolution methane data during the abrupt onset of Greenland interstadials. The ice and gas chronologies and the corresponding thinning function represent the first chronology for the NEEM core, named GICC05modelext-NEEM-1. Based on both the flow and firn modelling results, the accumulation history for the NEEM site has been reconstructed. Together, the timescale and accumulation reconstruction provide the necessary basis for further analysis of the records from NEEM.

scholarly journals Glacial Stage Ice-Core Records from the Subtropical Dunde Ice Cap, China

1990 ◽  
Vol 14 ◽  
pp. 288-297 ◽  
Author(s):  
L.G. Thompson ◽  
E. Mosley-Thompson ◽  
M.E. Davis ◽  
J.F. Bolzan ◽  
J. Dai ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Major Change ◽  
Late Glacial ◽  
Ice Cap ◽  
The North ◽  
Glacial Stage ◽  
Isotope Record ◽  
Temperature Proxy

The first ice-core record of both the Holocene and Wisconsin/Würm Late Glacial Stage (LGS) from the subtropics has been extracted from three ice cores to bedrock from the Dunde ice cap on the north-central Qinghai-Tibetan Plateau. Ice thicknesses at the ice-cap summit average 138 m, the bedrock surface is relatively flat, surface and basal temperatures are −7.3 and −4.7°C, respectively and the ice cap exhibits radial flow away from the summit dome. These records reveal a major change in the climate of the plateau ∼10 000 years ago and suggest that LGS conditions were colder, wetter and dustier than Holocene conditions. This is inferred from the more negative δ18O ratios, increased dust content, decreased soluble aerosol concentrations, and reduced ice-crystal sizes, which characterize the LGS part of the cores. Total β radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been ∼400 mm a−1 at the summit. The ice cores have been dated using a combination of annual layers in the insoluble dust and δ18O in the upper sections of core, visible dust layers which are annual, and ice-flow modeling. The oxygen-isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record.

scholarly journals Air Content Of The Byrd Core And Past Changes In The West Antarctic Ice Sheet

1982 ◽  
Vol 3 ◽  
pp. 269-273 ◽  
Author(s):  
D. Raynaud ◽  
I. M. Whillans
Keyword(s):  
Stable Isotope ◽  
Accumulation Rate ◽  
Ice Core ◽  
Ice Sheet ◽  
Ice Cores ◽  
Isotope Ratios ◽  
Ice Age ◽  
Gas Content ◽  
Stable Isotope Ratios ◽  
Antarctic Ice Sheet

Analyses of ice cores taken from the Antarctic ice sheet can provide information on the environmental conditions under which the ice was formed. New results from measurements of gas content and stable isotope ratios in the Byrd station ice core are discussed and interpreted in terms of past iceflow changes.165 selected ice samples from 32 different depth levels along the core were processed for total gas content V and stable isotope ratios. This large dataset is used to discuss the variability and significance of the values of V at different depths. The short term variations of V are mainly explained by heterogeneities of the pore volume when the firn pores close off.The general trends in the values of V with depth are then used to investigate the possibility of past changes in the ice sheet. They suggest near-steady flow during the past few tens of thousands of years and that a thickening of about 200 to 250 m occurred in this area of the ice sheet at the end of the last ice age. This thickening could be due to a change in the accumulation rate.

scholarly journals Volcanic fluxes over the last millennium as recorded in the GV7 ice core (Northern Victoria Land, Antarctica)

2020 ◽  
Author(s):  
Rita Traversi ◽  
Silvia Becagli ◽  
Mirko Severi ◽  
Raffaello Nardin ◽  
Laura Caiazzo ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Volcanic Eruptions ◽  
Deposition Flux ◽  
Last Millennium ◽  
Regional Variability ◽  
High Accumulation ◽  
Continental Scale ◽  
Victoria Land

<p>Explosive volcanic eruptions are able to affect significantly the atmosphere for 2‐3 years. During this time, volcanic products (mainly H2SO4) with high residence 
time are stored in the stratosphere/troposphere, and eventually deposited onto polar ice caps; snow layers may thus record signals providing a history of past 
volcanic events. A high resolution sulphate concentration profile along a 197 m long ice core drilled at GV7 (Northern Victoria Land) was obtained by Ion Chromatography. The relatively high accumulation rate (241±13 mm we yr<sup>-1</sup>) and the 5‐cm resolution allowed a preliminary counted age scale. The obtained stratigraphy covers roughly the last millennium and 24 major volcanic eruptions were identified, dated and 
ascribed to a source volcano. The deposition flux of volcanic sulfate was calculated and the results were compared with data from other Antarctic ice cores at regional and continental scale. Our results show that the regional variability is of the same order of magnitude 
of the continental scale.</p>

scholarly journals Reconstruction of annual accumulation rate on firn, synchronising H<sub>2</sub>O<sub>2</sub> concentration data with an estimated temperature record

2021 ◽  
Vol 15 (7) ◽  
pp. 3495-3505
Author(s):  
Jandyr M. Travassos ◽  
Saulo S. Martins ◽  
Mariusz Potocki ◽  
Jefferson C. Simões
Keyword(s):  
Antarctic Peninsula ◽  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Data Series ◽  
Temperature Record ◽  
Concentration Data ◽  
High Accumulation ◽  
Operational Life ◽  
The Antarctic

Abstract. This work deals with reconstructing firn layer thicknesses at the deposition time from the firn's observed thickness in ice cores, thus reconstructing the annual accumulation, yielding a timescale and an ice-core chronology. We employed a dynamic time warping algorithm to find an optimal, non-linear alignment between an H2O2 concentration data series from 98 m worth of ice cores of a borehole on the central ice divide of the Detroit Plateau, the Antarctic Peninsula, and an estimated local temperature time series. The viability and the physical reliability of the procedure are rooted in the robustness of the seasonal marker H2O2 in a high-accumulation context, which brought the entire borehole to within the operational life span of four Antarctic stations around the Antarctic Peninsula. The process was heavily based on numerical optimisation, producing a mathematically sound match between the two series to estimate the annual layering efficiently on the entire data section at once, being disposition-free. The results herein confirm a high annual accumulation rate of aN=2.8 m w.e./yr, which is of the same order of magnitude as and highly correlated with that of the Bruce Plateau and twice as large as that of the Gomez Plateau, 300 and 1200 km further south, respectively.

scholarly journals Alpine ice-core drilling in the North Pacific region

2014 ◽  
Vol 55 (68) ◽  
pp. 83-87 ◽  
Author(s):  
Sumito Matoba ◽  
Kunio Shimbori ◽  
Takayuki Shiraiwa
Keyword(s):  
North Pacific ◽  
Ice Core ◽  
Ice Cores ◽  
Kamchatka Peninsula ◽  
Pacific Region ◽  
Alaska Range ◽  
Core Drilling ◽  
The North ◽  
Summit Caldera ◽  
North Pacific Region

AbstractThe Institute of Low Temperature Science at Hokkaido University conducted ice-core drilling in alpine glaciers in the northern North Pacific region to reconstruct climate change in this region for the past few hundred years. We drilled two ice cores in the Kamchatka Peninsula, Russia. An ice core with a length of 211 m was drilled on a glacier at the summit caldera of Ushkovsky mountain in 1998. A second core, with a length of 115m (until bedrock was reached), was drilled on a glacier at the summit caldera of Ichinsky mountain in 2006. We drilled three further ice cores in Alaska, USA. Two ice cores with lengths of 50 and 212m were drilled on a glacier at the summit caldera of Mount Wrangell in 2003 and 2004. The third ice core was drilled on the ice divide among three glaciers, Black Rapids, Trident and Susitna glaciers, which represent a flat saddle north of Aurora Peak in the Alaska Range. This paper details the field operations and characteristics of the different ice-drilling systems used and the problems encountered.

scholarly journals Glacial Stage Ice-Core Records from the Subtropical Dunde Ice Cap, China

1990 ◽  
Vol 14 ◽  
pp. 288-297 ◽  
Author(s):  
L.G. Thompson ◽  
E. Mosley-Thompson ◽  
M.E. Davis ◽  
J.F. Bolzan ◽  
J. Dai ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Major Change ◽  
Late Glacial ◽  
Ice Cap ◽  
The North ◽  
Glacial Stage ◽  
Isotope Record ◽  
Temperature Proxy

The first ice-core record of both the Holocene and Wisconsin/Würm Late Glacial Stage (LGS) from the subtropics has been extracted from three ice cores to bedrock from the Dunde ice cap on the north-central Qinghai-Tibetan Plateau. Ice thicknesses at the ice-cap summit average 138 m, the bedrock surface is relatively flat, surface and basal temperatures are −7.3 and −4.7°C, respectively and the ice cap exhibits radial flow away from the summit dome. These records reveal a major change in the climate of the plateau ∼10 000 years ago and suggest that LGS conditions were colder, wetter and dustier than Holocene conditions. This is inferred from the more negative δ18O ratios, increased dust content, decreased soluble aerosol concentrations, and reduced ice-crystal sizes, which characterize the LGS part of the cores. Total β radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been ∼400 mm a−1 at the summit. The ice cores have been dated using a combination of annual layers in the insoluble dust and δ18O in the upper sections of core, visible dust layers which are annual, and ice-flow modeling. The oxygen-isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record.

scholarly journals A Synoptic Scale Perspective on Greenland Ice Core δ18O Variability and Related Teleconnection Patterns

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 294
Author(s):  
Norel Rimbu ◽  
Monica Ionita ◽  
Gerrit Lohmann
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Synoptic Scale ◽  
Local Climate ◽  
Rossby Wave Breaking ◽  
Weather Patterns ◽  
Teleconnection Patterns ◽  
Climate Anomalies ◽  
The North ◽  
Oxygen Isotope Ratios

The variability of stable oxygen isotope ratios (δ18O) from Greenland ice cores is commonly linked to changes in local climate and associated teleconnection patterns. In this respect, in this study we investigate ice core δ18O variability from a synoptic scale perspective to assess the potential of such records as proxies for extreme climate variability and associated weather patterns. We show that positive (negative) δ18O anomalies in three southern and central Greenland ice cores are associated with relatively high (low) Rossby Wave Breaking (RWB) activity in the North Atlantic region. Both cyclonic and anticyclonic RWB patterns associated with high δ18O show filaments of strong moisture transport from the Atlantic Ocean towards Greenland. During such events, warm and wet conditions are recorded over southern, western and central part of Greenland. In the same time the cyclonic and anticyclonic RWB patterns show enhanced southward advection of cold polar air masses on their eastern side, leading to extreme cold conditions over Europe. The association between high δ18O winters in Greenland ice cores and extremely cold winters over Europe is partly explained by the modulation of the RWB frequency by the tropical Atlantic sea surface temperature forcing, as shown in recent modeling studies. We argue that δ18O from Greenland ice cores can be used as a proxy for RWB activity in the Atlantic European region and associated extreme weather and climate anomalies.

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