Holocene climatic changes in Greenland: Different deuterium excess signals at Greenland Ice Core Project (GRIP) and NorthGRIP

AbstractThis paper presents a high-resolution ice-core pollen record from the Sajama Ice Cap, Bolivia, that spans the last 400 yr. The pollen record corroborates the oxygen isotopic and ice accumulation records from the Quelccaya Ice Cap and supports the scenario that the Little Ice Age (LIA) consisted of two distinct phases�"a wet period from AD 1500 to 1700, and a dry period from AD 1700 to 1880. During the dry period xerophytic shrubs expanded to replace puna grasses on the Altiplano, as suggested by a dramatic drop in the Poaceae/Asteraceae (P/A) pollen ratio. The environment around Sajama was probably similar to the desert-like shrublands of the Southern Bolivian Highlands and western Andean slopes today. The striking similarity between the Sajama and Quelccaya proxy records suggests that climatic changes during the Little Ice Age occurred synchronously across the Altiplano.

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A novel high-resolution laser-melting sampler for discrete analyses of ion concentrations and stable water isotopic compositions in firn and ice cores

10.5194/egusphere-egu21-7935 ◽

2021 ◽

Author(s):

Yuko Motizuki ◽

Yoichi Nakai ◽

Kazuya Takahashi ◽

Junya Hirose ◽

Yu Vin Sahoo ◽

...

Keyword(s):

Ice Core ◽

Ice Cores ◽

Depth Resolution ◽

Climatic Changes ◽

Accumulation Rates ◽

Laser Melting ◽

Ion Concentrations ◽

Annual Layer ◽

Annual Resolution ◽

High Depth

Ice cores preserve past climatic changes and, in some cases, astronomical signals. Here we present a newly developed automated ice-core sampler that employs laser melting. A hole in an ice core approximately 3 mm in diameter is melted and heated well below the boiling point by laser irradiation, and the meltwater is simultaneously siphoned by a 2 mm diameter movable evacuation nozzle that also holds the laser fiber. The advantage of sampling by laser melting is that molecular ion concentrations and stable water isotope compositions in ice cores can be measured at high depth resolution, which is advantageous for ice cores with low accumulation rates. This device takes highly discrete samples from ice cores, attaining depth resolution as small as ~3 mm with negligible cross contamination; the resolution can also be set at longer lengths suitable for validating longer-term profiles of various ionic and water isotopic constituents in ice cores. This technique allows the detailed reconstruction of past climatic changes at annual resolution and the investigation of transient ionic and isotopic signals within single annual layers in low-accumulation cores, potentially by annual layer counting.

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Response of Siberian trees to climatic changes over the past 1500 years

10.5194/egusphere-egu21-8995 ◽

2021 ◽

Author(s):

Olga Churakova (Sidorova) ◽

Marina Fonti ◽

Rolf Siegwolf ◽

Tatyana Trushkina ◽

Eugene Vaganov ◽

...

Keyword(s):

Tree Ring ◽

Ice Core ◽

Climatic Changes ◽

Medieval Warm Period ◽

Warm Period ◽

Taimyr Peninsula ◽

Climate Conditions ◽

Northeastern Part ◽

The Past ◽

Tree Ring Cellulose

We use an interdisciplinary approach combining stable isotopes in tree rings, pollen data, ice cores from temperature-limited environment in the Siberian north and developed a comprehensive description of the climatic changes over the past 1500 years. We found that the Climatic Optimum Period was warmer and drier compared to the Medieval one, but rather similar to the recent period. Our results indicate that the Medieval Warm period in the Taimyr Peninsula started earlier and was wetter compared to the northeastern part of Siberia (northeastern Yakutia). Summer precipitation reconstruction obtained from carbon isotopes in tree-ring cellulose from Taimyr Peninsula significantly correlated with the pollen data of the Lama Lake (Andreev et al. 2004) and oxygen isotopes of the ice core from Severnaya Zemlya (Opel et al. 2013) recording wetter climate conditions during the Medieval Warm period compared to the northeastern part of Siberia. Common large-scale climate variability was confirmed by significant relationship between oxygen isotope data in tree-ring cellulose from the Taimyr Peninsula and northeastern Yakutia, and oxygen isotope ice core data from Severnaya Zemlja during the Medieval Warm period and the recent one. Finally, we showed that the recent warming on the Taimyr Peninsula is not unprecedented in the Siberian north. Similar climate conditions were recorded by stable isotopes in tree rings, pollen, and ice core data 6000 years ago. On the northeastern part of Siberia newly developed a 1500-year summer vapor pressure deficit (VPD) reconstruction showed, that VPD increased recently, but does not yet exceed the maximum values reconstructed during the Medieval Warm period. The most humid conditions in the northeastern part of Siberia were recorded in the Early Medieval period and during the Little Ice Age. However, the increasing VPD under elevated air temperature in the last decades affects the hydrological regime of these sensitive ecosystems by greater evapotranspiration rates. Further VPD increase will significantly affect Siberian forests most likely leading to drought even under additional access of thawed permafrost water.This work was supported by the FP7-PEOPLE-IIF-2008 - Marie Curie Action: "International Incoming Fellowships" 235122 and "Reintegration Fellowships" 909122 &#8220;Climatic and environmental changes in the Eurasian Subarctic inferred from tree-ring and stable isotope chronologies for the past and recent periods&#8221; and the Government of Krasnoyarsk Kray and Russian Foundation for Basic Research and Krasnoyarsk Foundation 20-44-240001 &#8220;Adaptation of conifer forests on the north of the Krasnoyarsk region (Taimyr Peninsula) to climatic changes after extreme events over the past 1500 years&#8220; awarded to Olga V. Churakova (Sidorova).

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Continental biogenic species in the Greenland Ice Core Project ice core: Tracing back the biomass history of the North American continent

Journal of Geophysical Research Atmospheres ◽

10.1029/97jc01299 ◽

1997 ◽

Vol 102 (C12) ◽

pp. 26735-26745 ◽

Cited By ~ 33

Author(s):

Katrin Fuhrer ◽

Michel Legrand

Keyword(s):

North American ◽

Ice Core ◽

American Continent ◽

North American Continent ◽

The North ◽

History Of ◽

Core Project

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Air clathrate crystals from the GRIP deep ice core, Greenland: a number-, size- and shape-distribution study

Journal of Glaciology ◽

10.1017/s0022143000003002 ◽

1999 ◽

Vol 45 (149) ◽

pp. 22-30 ◽

Cited By ~ 32

Author(s):

F. Pauer ◽

S. Kipfstuhl ◽

W. F. Kuhs ◽

H. Shoji

Keyword(s):

Diffusion Processes ◽

Climatic Factors ◽

Ice Core ◽

Number Concentration ◽

Depth Range ◽

Shape Distribution ◽

Climatic Oscillations ◽

Size And Shape ◽

Distribution Study ◽

Core Project

AbstractWe performed microscopic observations and a statistical study of the number, size and shape distribution of clathrates in the GRIP (Greenland Ice Core Project) deep ice core, using 185 samples from a depth range of 1016–3014 m, spanning a period of 6 to >110 ka BP and encompassing the Holocene, Wisconsin and Eemian periods. The number concentration of the clathrates varied considerably with climatic changes. It was possible to detect the rapid climatic oscillations in the last glacial between 13 and 110 ka BP, the Dansgaard–Oeschger cycles, in the number-concentration profile of clathrates. The mean volume of clathrates is less clearly influenced by climatic factors, with a tendency towards greater volumes in warmer periods, but also a growth of clathrates with depth could be detected. This growth rate was calculated to be 3.1 × 10-12 cm3 a-1. The amount of gases captured in the clathrates is estimated to be significantly smaller than the total amount of air determined by gas-concentration measurements. This points to diffusion processes of atmospheric gases within the ice matrix.

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Crystal growth of air hydrates over 720 ka in Dome Fuji (Antarctica) ice cores: microscopic observations of morphological changes below 2000 m depth

Journal of Glaciology ◽

10.3189/002214311798843296 ◽

2011 ◽

Vol 57 (206) ◽

pp. 1017-1026 ◽

Cited By ~ 10

Author(s):

Tsutomu Uchida ◽

Atsushi Miyamoto ◽

Atsushi Shin’yama ◽

Takeo Hondoh

Keyword(s):

Crystal Growth ◽

Morphological Changes ◽

Ice Core ◽

Ice Sheets ◽

Ice Sheet ◽

Ice Cores ◽

Climatic Changes ◽

Size Distributions ◽

Number Density ◽

Average Size

AbstractAir-hydrate crystals store most of the ancient air contained in deep ice sheets. We carried out microscopic observations of air-hydrate crystals below 2000 m depth within the ice core from Dome Fuji, Antarctica, to obtain their number and size distributions. We found that the number density continuously decreased with depth, whereas the average size increased, in contrast to findings from shallower depths. In addition, the characteristic perturbations in both number density and average size distribution with climatic changes almost disappeared, although they are clearly observed in shallow cores. These results indicate that the air-hydrate crystals grow considerably in deeper parts of the ice sheet, and this growth is accompanied by the diffusion of air molecules in the ice. The permeation coefficient of the air molecules in the ice sheet was estimated from the geometric parameters of the air-hydrate distributions. This is the first practical evidence comparable to the previous model estimations. It allows us to evaluate the impacts of the air-molecule migration in the ice sheet on the paleoclimatic information recorded in the deep ice cores.

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Surface accumulation in Northern Central Greenland during the last 300 years

Annals of Glaciology ◽

10.1017/aog.2020.30 ◽

2020 ◽

Vol 61 (81) ◽

pp. 214-224 ◽

Cited By ~ 2

Author(s):

Nanna B. Karlsson ◽

Sebastian Razik ◽

Maria Hörhold ◽

Anna Winter ◽

Daniel Steinhage ◽

...

Keyword(s):

Large Scale ◽

Climate Models ◽

Regional Climate ◽

Ice Core ◽

Regional Climate Models ◽

Radar Data ◽

Accumulation Rates ◽

Ground Penetrating ◽

Core Project ◽

North Greenland

AbstractThe internal stratigraphy of snow and ice as imaged by ground-penetrating radar may serve as a source of information on past accumulation. This study presents results from two ground-based radar surveys conducted in Greenland in 2007 and 2015, respectively. The first survey was conducted during the traverse from the ice-core station NGRIP (North Greenland Ice Core Project) to the ice-core station NEEM (North Greenland Eemian Ice Drilling). The second survey was carried out during the traverse from NEEM to the ice-core station EGRIP (East Greenland Ice Core Project) and then onwards to Summit Station. The total length of the radar profiles is 1427 km. From the radar data, we retrieve the large-scale spatial variation of the accumulation rates in the interior of the ice sheet. The accumulation rates range from 0.11 to 0.26 m a−1 ice equivalent with the lowest values found in the northeastern sector towards EGRIP. We find no evidence of temporal or spatial changes in accumulation rates when comparing the 150-year average accumulation rates with the 321-year average accumulation rates. Comparisons with regional climate models reveal that the models underestimate accumulation rates by up to 35% in northeastern Greenland. Our results serve as a robust baseline to detect present changes in either surface accumulation rates or patterns.

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Paleoclimate Changes during the last 100,000 yr from a Record in the Brazilian Atlantic Rainforest region and Interhemispheric Comparison

Quaternary Research ◽

10.1016/j.yqres.2005.08.006 ◽

2005 ◽

Vol 64 (3) ◽

pp. 444-450 ◽

Cited By ~ 90

Author(s):

M.-P. Ledru ◽

D.-D. Rousseau ◽

F.W. Cruz ◽

C. Riccomini ◽

I. Karmann ◽

...

Keyword(s):

Global Climate ◽

Ice Core ◽

Climatic Changes ◽

Climate Forcing ◽

Atlantic Rainforest ◽

Tropical Atlantic ◽

Forest Expansion ◽

Last Glaciation ◽

Arboreal Pollen ◽

Brazilian Atlantic Rainforest

AbstractA long terrestrial record, Colônia CO-3, from the Atlantic rainforest region in Brazil (23°52′S, 46°42′20 ʺW, 900 m a.s.l.) registrates variations in the forest expansion during the last 100,000 yr. The 780-cm depth core was analyzed at 2-cm intervals and arboreal pollen frequencies were compared to nearby speleothem stable isotope records and neighboring marine records from the tropical Atlantic. To evaluate regional versus global climate forcing, our record was compared with Greenland and Antarctic ice-core records. These comparisons suggest that changes in temperature seen in polar latitudes relate to moisture changes: e.g., to changes in the length of the dry season, in tropical and subtropical latitudes during glacial as well as interglacial times. These climatic changes result from changes in the frequency of polar air incursions to these latitudes inducing a permanent cloud cover and precipitation. This is an important result that should help define paleoclimatic features in the Southern Hemisphere for the last glaciation.

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