scholarly journals NGRIP CH<sub>4</sub> concentration from 120 to 10 kyr before present and its relation to a δ<sup>15</sup>N temperature reconstruction from the same ice core

2014 ◽  
Vol 10 (2) ◽  
pp. 903-920 ◽  
Author(s):  
M. Baumgartner ◽  
P. Kindler ◽  
O. Eicher ◽  
G. Floch ◽  
A. Schilt ◽  
...  
Keyword(s):  
Ice Core ◽  
High Ratio ◽  
Interglacial Period ◽  
Atmospheric Methane ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Concentration Difference ◽  
Temperature Variations ◽  
Last Glacial ◽  
The Last Glacial

Abstract. During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so-called Dansgaard–Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from the Preboreal Holocene (PB) back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the local Greenland NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core (Kindler et al., 2014). We find the ratio to oscillate between 5 parts per billion (ppb) per °C and 18 ppb °C−1 with the approximate frequency of the precessional cycle. A remarkably high ratio of 25.5 ppb °C−1 is reached during the transition from the Younger Dryas (YD) to the PB. Analysis of the timing of the fast methane and temperature increases reveals significant lags of the methane increases relative to NGRIP temperature for DO events 5, 9, 10, 11, 13, 15, 19, and 20. These events generally have small methane increase rates and we hypothesize that the lag is caused by pronounced northward displacement of the source regions from stadial to interstadial. We further show that the relative interpolar concentration difference (rIPD) of methane is about 4.5% for the stadials between DO events 18 and 20, which is in the same order as in the stadials before and after DO event 2 around the Last Glacial Maximum. The rIPD of methane remains relatively stable throughout the full last glacial, with a tendency for elevated values during interstadial compared to stadial periods.

scholarly journals NGRIP CH<sub>4</sub> concentration from 120 to 10 kyr before present and its relation to a δ<sup>15</sup>N temperature reconstruction from the same ice core

2013 ◽  
Vol 9 (4) ◽  
pp. 4655-4704 ◽  
Author(s):  
M. Baumgartner ◽  
P. Kindler ◽  
O. Eicher ◽  
G. Floch ◽  
A. Schilt ◽  
...  
Keyword(s):  
Ice Core ◽  
High Sensitivity ◽  
Interglacial Period ◽  
Atmospheric Methane ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Concentration Difference ◽  
Temperature Variations ◽  
Last Glacial ◽  
The Last Glacial

Abstract. During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so called Dansgaard-Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from Termination 1 back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core. We find the sensitivity to oscillate between 5 parts per billion by volume (ppbv) per °C and 18 ppbv °C−1 with the approximate frequency of the precessional cycle. A remarkably high sensitivity of 25.5 ppbv °C−1 is reached during Termination 1. Analysis of the timing of the fast methane and temperature increases reveals significant lags of the methane increases relative to NGRIP temperature for the DO events 5, 9, 10, 11, 13, 15, 19, and 20. We further show that the relative interpolar concentration difference of methane is 4.6 ± 0.7% between the DO events 18 and 19 and 4.4 ± 0.8% between the DO events 19 to 20, which is in the same order as in the stadials before and after DO event 2 around the Last Glacial Maximum.

scholarly journals Iron in the NEEM ice core relative to Asian loess records over the last glacial–interglacial cycle

2020 ◽  
Author(s):  
Cunde Xiao ◽  
Zhiheng Du ◽  
Mike J Handley ◽  
Paul A Mayewski ◽  
Junji Cao ◽  
...  
Keyword(s):  
Industrial Revolution ◽  
Mineral Dust ◽  
Ice Core ◽  
Interglacial Period ◽  
Anthropogenic Contamination ◽  
Last Interglacial ◽  
Chinese Loess ◽  
Last Glacial ◽  
The Past ◽  
The Last Glacial

Abstract Mineral dust can indirectly affect the climate by supplying bioavailable iron (Fe) to the ocean. Here, we present the records of dissolved Fe (DFe) and total Fe (TDFe) in North Greenland Eemian Ice Drilling (NEEM) ice core over the past 110 kyr BP. The Fe records are significantly negatively correlated with the carbon-dioxide (CO2) concentrations during cold periods. The results suggest that the changes in Fe fluxes over the past 110 kyr BP in the NEEM ice core are consistent with those in Chinese loess records because the mineral-dust distribution is controlled by the East Asian deserts. Furthermore, the variations in the dust input on a global scale are most likely driven by changes in solar radiation during the last glacial–interglacial cycle in response to Earth's orbital cycles. In the last glacial–interglacial cycle, the DFe/TDFe ratios were higher during the warm periods (following the post-Industrial Revolution and during the Holocene and last interglacial period) than during the main cold period (i.e. the last glacial maximum (LGM)), indicating that the aeolian input of iron and the iron fertilization effect on the oceans have a non-linear relationship during different periods. Although the burning of biomass aerosols has released large amounts of DFe since the Industrial Revolution, no significant responses are observed in the DFe and TDFe variations during this period, indicating that severe anthropogenic contamination has no significant effect on the DFe (TDFe) release in the NEEM ice core.

scholarly journals Characteristics of air bubbles and hydrates in the Dome Fuji ice core, Antarctica

1999 ◽  
Vol 29 ◽  
pp. 207-210 ◽  
Author(s):  
Hideki Narita ◽  
Nobuhiko Azuma ◽  
Takeo Hondoh ◽  
Michiko Fujii ◽  
Mituo Kawaguchi ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Ice Core ◽  
Air Bubbles ◽  
Depth Range ◽  
Last Interglacial ◽  
Last Glacial ◽  
Maximum Period ◽  
Glacial Periods ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractAir bubbles trapped near the surface of an ice sheet are transformed into air hydrates below a certain depth Their volume and number varies partly with environment and climate. Air bubbles and hydrates at 120-2200 m depth in the Dome Fuji (Dome F) ice core were examined with a microscope. This depth range covers the Holocene/Last Glacial/Last Interglacial/Previous Glacial periods. No air bubbles were seen below about 1100 m depth, and air hydrates began to appear from about 600 m. The observed number of air bubbles and hydrates was similar to that found in the Vostok ice core. For the ice covering the Last Glacial Maximum period, however the hydrate concentration in the Dome F core is about half that of the Vostok core. Reference to snow metamorphism and packing does not explain this finding.

scholarly journals Radar stratigraphy connecting Lake Vostok and Dome C, East Antarctica, constrains the EPICA/DMC ice core time scale

2013 ◽  
Vol 7 (1) ◽  
pp. 321-342 ◽  
Author(s):  
M. G. P. Cavitte ◽  
D. D. Blankenship ◽  
D. A. Young ◽  
M. J. Siegert ◽  
E. Le Meur
Keyword(s):  
Ice Core ◽  
Airborne Radar ◽  
Glacial Cycle ◽  
Glacial Cycles ◽  
Last Glacial ◽  
Lake Vostok ◽  
The Last Glacial Maximum ◽  
Radar Technique ◽  
Ice Core Dating ◽  
The Last Glacial

Abstract. New airborne radar sounding surveys at 60 MHz are used to trace internal layering between the Vostok and EPICA Dome C ice core sites. Eleven layers, spanning two glacial cycles from the last glacial maximum back to the MIS 7c interglacial, are used to correlate the two ice core chronologies. Independent of palaeoclimate signals, radar sounding enables correlation of the timescales, with a radar depth uncertainty equivalent to hundreds of years, which is small relative to the ice core dating uncertainties of thousands of years. Along the radar transects, horizons belonging to the last glacial cycle are impacted by aeolian stratigraphic reworking that increases radar technique uncertainty for this interval. However, older layers are used to propagate the higher resolution Vostok ages to the lower resolution Dome C ice core using the Suwa and Bender (2008) Vostok O2 / N2 chronology to give a recalibration of the Parrenin et al. (2007) EPICA EDC3 timescale between 1597 m and 2216 m depth (126 ka to 247 ka age interval).

scholarly journals Atmospheric gas records from Taylor Glacier, Antarctica, reveal ancient ice with ages spanning the entire last glacial cycle

2017 ◽  
Vol 13 (7) ◽  
pp. 943-958 ◽  
Author(s):  
Daniel Baggenstos ◽  
Thomas K. Bauska ◽  
Jeffrey P. Severinghaus ◽  
James E. Lee ◽  
Hinrich Schaefer ◽  
...  
Keyword(s):  
Large Scale ◽  
Ice Core ◽  
Ice Sheet ◽  
Last Deglaciation ◽  
Glacial Cycle ◽  
Last Glacial ◽  
Climate Reconstructions ◽  
Age Model ◽  
Taylor Glacier ◽  
The Last Glacial

Abstract. Old ice for paleo-environmental studies, traditionally accessed through deep core drilling on domes and ridges on the large ice sheets, can also be retrieved at the surface from ice sheet margins and blue ice areas. The practically unlimited amount of ice available at these sites satisfies a need in the community for studies of trace components requiring large sample volumes. For margin sites to be useful as ancient ice archives, the ice stratigraphy needs to be understood and age models need to be established. We present measurements of trapped gases in ice from Taylor Glacier, Antarctica, to date the ice and assess the completeness of the stratigraphic section. Using δ18O of O2 and methane concentrations, we unambiguously identify ice from the last glacial cycle, covering every climate interval from the early Holocene to the penultimate interglacial. A high-resolution transect reveals the last deglaciation and the Last Glacial Maximum (LGM) in detail. We observe large-scale deformation in the form of folding, but individual stratigraphic layers do not appear to have undergone irregular thinning. Rather, it appears that the entire LGM–deglaciation sequence has been transported from the interior of the ice sheet to the surface of Taylor Glacier relatively undisturbed. We present an age model that builds the foundation for gas studies on Taylor Glacier. A comparison with the Taylor Dome ice core confirms that the section we studied on Taylor Glacier is better suited for paleo-climate reconstructions of the LGM due to higher accumulation rates.

Controls on the East Asian monsoon during the last glacial cycle, based on comparison between Hulu Cave and polar ice-core records

2009 ◽  
Vol 28 (27-28) ◽  
pp. 3291-3302 ◽  
Author(s):  
E.J. Rohling ◽  
Q.S. Liu ◽  
A.P. Roberts ◽  
J.D. Stanford ◽  
S.O. Rasmussen ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Ice Core ◽  
Glacial Cycle ◽  
Polar Ice ◽  
Last Glacial ◽  
The Last Glacial ◽  
Ice Core Records

The Taylor Dome Antarctic 18O Record and Globally Synchronous Changes in Climate

2001 ◽  
Vol 56 (3) ◽  
pp. 289-298 ◽  
Author(s):  
Pieter M. Grootes ◽  
Eric J. Steig ◽  
Minze Stuiver ◽  
Edwin D. Waddington ◽  
David L. Morse ◽  
...  
Keyword(s):  
Thermohaline Circulation ◽  
Ice Core ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Conflicting Evidence ◽  
Last Interglacial Period ◽  
Stage 4 ◽  
Marine Influence ◽  
Atlantic Thermohaline Circulation ◽  
The Last Glacial

AbstractThe 18O/16O profile of a 554-m long ice core through Taylor Dome, Antarctica, shows the climate variability of the last glacial–interglacial cycle in detail and extends at least another full cycle. Taylor Dome shares the main features of the Vostok record, including the early climatic optimum with later cool phase of the last interglacial period in Antarctica. Taylor Dome δ18O fluctuations are more abrupt and larger than those at Vostok and Byrd Station, although still less pronounced than those of the Greenland GISP2 and GRIP records. The influence of the Atlantic thermohaline circulation on regional ocean heat transport explains the partly “North Atlantic” character of this Antarctic record. Under full glacial climate (marine isotope stage 4, late stage 3, and stage 2), this marine influence diminished and Taylor Dome became more like Vostok. Varying degrees of marine influence produce climate heterogeneity within Antarctica, which may account for conflicting evidence regarding the relative phasing of Northern and Southern Hemisphere climate change.

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