This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Ice Core. The data include parameters of ice cores with a geographic location of Greenland. The time period coverage is from 50000 to 0 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5 °C warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time.

Prediction of future climate change requires knowledge of past changes. Polar snow forms an archive of environmental conditions that is accessible by drilling and analysing ice cores. This project uses ice core data to reconstruct records, including past temperature and atmospheric composition, to improve understanding of the climate system.

Report from the 2007/2008 season
This proposal encompasses the laboratory-based component of ice core research at the Australian Antarctic Division. The project is principally focused on analysis of currently archived ice core material but will include analysis of new cores (to be collected in future field activities that will be the subject of separate research proposals through the duration of the project). This work is conducted as part of the ACE-CRC (Antarctic Climate and Ecosystems Cooperative Research Centre).

The overall general aim for this AAS project is to understand past climate variability and change, through the study of Antarctic ice cores. More specifically, this research explores the role of Antarctica in hemispheric and global climate, with particular emphasis on climate variability and change in the Southern Ocean, mid-latitudes, and the Australian sector. To effectively achieve this aim, we have defined four research questions, broadly based on a separation at different temporal and spatial scales:

1. What do high resolution comparisons of instrumental climate data and ice cores reveal about calibration of ice core signals and underlying mechanisms?
2. What is the spatial and temporal variability in climate across the wider East Antarctic region in the last few centuries, particularly spanning the onset of anthropogenic influence? How is this connected with overall variability in the Antarctic, and the Southern Ocean, particularly the Australian sector?
3. What changes and modes of variability are seen in Holocene Antarctic and Southern Ocean climate from high resolution ice cores?
4. What climate changes were seen in coastal Antarctica through the last glacial and deglaciation, and how does the timing compare with other records, especially the Northern Hemisphere records?

Feeding into these research questions are a number of specific scientific objectives (listed below, with clearly identified methodology to achieve outcomes). These objectives address issues essential to a number of research fields across the Australian Antarctic program (see 3.1.3), and have been identified through knowledge gained from the earlier AAS project 757 and the scientific literature (discussed in more detail in section 3.1.2). Research will use high-resolution ice core studies as a tool to probe climate variability on timescales from seasonal through to millennial. This ability to access very high resolution climate records through ice cores is of major importance because it is the only means of calibrating the ice core recorder against observed meteorology. Also, the seasonal- to interannual-timescales capture climate variability that is not readily probed in other records. The high snow accumulation on Law Dome, combined with a 1.2km thick ice sheet, provides a unique high resolution record of the Holocene and access to the last Glacial-interglacial cycle.

The main objectives are listed below, with a brief explanation of the methodology employed to achieve these objectives:
- Extend the time-series of ice core chemical and physical measurements
- Focussed on East Antarctic sites, (particularly Law Dome). The length and resolution of records so far obtained will be increased and the range of measured parameters increased. This includes from the DSS core: completion of a full 90 thousand year record of trace ion data to accompany the completed d18O isotope series; high-resolution (subannual) series for trace ions and d18O over the last 2000 years; new measurements including d13CH4 (and potentially dCH3D) in collaboration with University of Colorado, NIWA and CSIRO and deuterium excess measurements using new mass-spectrometry facilities.

- Calibrate ice core measurements against instrumental records
- Calibrate ice core measurements against meteorological, and other proxy series, in order to better understand the climate signals in ice cores and to provide new proxies. This work will use ultra-high resolution data, especially through the period of instrumental overlap (for Antarctic records, this period covers the nearly 50 years since the first IGY). The study is expected to draw data from a field activity in 2008/09 summer in conjunction with IPY, which has a 'special observing period' for tracking airmasses arriving at ice core sites.


- Investigate modes of climate variability
- Investigate the strength, variability and alteration in modes of variability for specific climate processes, especially to examine any recent changes in these from Holocene background. In particular, processes or indices that will be explored include ENSO, the Southern Annular Mode, sea-ice extent, decadal variability in coupled ocean-atmosphere modes such as the Antarctic Circumpolar Wave (White and Peterson, 1996), atmospheric circulation indices (e.g. stratospheric markers such as nitrate or beryllium-10 and dust or trace-metal variations).

- Examine response and sensitivity to forcing variations and explore mechanisms
- This includes studies of: insolation links to climate variability, the timing and magnitude of major volcanic events, and variations associated with atmospheric composition changes (the '8200 BP' event, deglacial interhemispheric climate variations and abrupt changes in the last glacial).

- Improve the understanding of the Antarctic climate system using multiple records
- Explore relationships between the high resolution ice core records and other ice cores including the Antarctic interior to better understand both the spatial structure of the Antarctic climate system (including teleconnections), and the interpretation of the ice cores themselves.

- Contribute to Antarctic mass-balance and sea-level rise
- Derive records of accumulation input and variability for the last 100-200 years at sites in eastern Wilkes Land and for the last 90 thousand years at Law Dome. These records contribute to understanding Antarctic mass-balance and sea-level impacts.

- Develop and maintain facilities and expertise for analysis of ice cores
- Continue to develop and maintain facilities and expertise for analysis of ice cores and related climate studies. The facilities supported by this project provide a core capacity for downstream analysis and interpretation of Australian field studies, by the AAD, and also by collaborative partners in CSIRO, University of Newcastle, Curtin University of Technology as well as several important international partnerships.

In the last 12 months, the project has predominantly been in a laboratory/measurement phase and so progress is predominantly against the first and last objectives at 1.1 (Extend time series, Develop facilities). The isotope and trace chemistry records for the Law Dome cores are being extended and in-filled where gaps occur. The time series have been extended. Most measurements have been undertaken using recently drilled new core material (DSS0506 from AAS2384), as this is providing an opportunity to derive new series (deuterium) and check existing data for inter-core fidelity. New core material which brings records up to January 2008 has been analysed and the data are being combined with other cores to provide continuous series.

For the interpretive objectives, progress consists predominantly of results that have so far been presented at various meetings. We now have new data that strongly mitigate against the "EPICA hypothesis" that posits that sea-salts in ice cores (particularly inland cores) are specifically connected with sea-ice extent. We are able to quantify the degree of influence of sea-ice surface as a source of salt and demonstrate that it decreases with distance from the coast. We have further investigated the snowfall accumulation at Law Dome and are probing links seen to rainfall in Southwest Western Australia. We have also investigated subannual variations in snowfall accumulation and find that winter accumulation variability dominates the annual signal. We have new results from very high resolution studies of beryllium-10 which demonstrate a shorter atmospheric residence time for this cosmogenically produced species than has been accepted. This work has potential to improve the use of beryllium-10 as a proxy for solar variability and has implications for understanding of atmospheric transport.

Taken from the 2008-2009 Progress Report:
Progress against objectives:
This year's activities have been focused upon data generation and also with associated fieldwork for AAS 3025 (Aurora Basin North Ice Core Drilling). A deliberate slowing of progress on AAS 757 this year was planned because of a large investment of personnel time toward AAS 3025, however good progress has nevertheless been made.
While the intention of AAS 3025 was to generate data within an independent project, field constraints forced a change to theatre of operations - providing core material that now fits within the scope of this project. This fieldwork produced ~130m of core from a new site on Law Dome (DSSW10k), extensions of the record at Law Dome Summit South (10m), new cores on the lower Totten Glacier (~17m) and Totten-Law Dome Trench (~15m) and Mill Is (~17m). Analysis of these cores within AAS 757 has already commenced.
The DSSW10k core provides a new ~250 year record from Law Dome that will be useful in its own right, but will provide an opportunity to test both deposition processes and ice core proxy fidelity. The core comes

This data set contains ice core chemistry, timescale, isotope, and temperature data analyzed by several investigators. In January 1998, the collaborative ice-drilling project between Russia, the United States, and France at the Russian Vostok station in East Antarctica yielded the deepest ice core ever recovered, reaching a depth of 3,623 m. Preliminary data indicate the Vostok ice-core record extends through four climate cycles, with ice slightly older than 400 kyr.

This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Ice Core. The data include parameters of ice cores with a geographic location of Greenland. The time period coverage is from 248763 to -39 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Ice Core. The data include parameters of ice cores with a geographic location of Greenland. The time period coverage is from 123001 to 9700 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

This data set includes ice core water isotope data from Antarctic ice cores covering the last 200 to 2000 years.

A high-resolution deuterium profile is now available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage 20.2, ~800,000 years ago. Experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation. We assessed the general correspondence between Dansgaard-Oeschger events and their smoothed Antarctic counterparts for this Dome C record, which reveals the presence of such features with similar amplitudes during previous glacial periods. We suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records. […]

This data set includes a time scale for the Vostok ice core, retrieved from Vostok Station on the East Antarctic Plateau. This chronology is derived by orbitally tuning to molecular oxygen to nitrogen (O₂/N₂) ratios in occluded air for depths deeper than 1550 m (greater than 112,000 years old), and by gas correlation to the Greenland Ice Sheet Project 2 (GISP2) chronology for the ice core section that is shallower than 1422 m (less than 102,000 years old). Because of poor gas preservation in air bubbles in shallower depths, investigators could only constrain the Vostok chronology for the section deeper than 1550 m by O₂/N₂. Thus for the shallower section of the core, they synchronized the Vostok delta oxygen-18 (δ¹⁸O) and methane (CH₄) measurements to those of the GISP2 to obtain the chronology (see Bender, et al. 2006). Note, CH₄ data are not included in this data set.

Investigators analyzed the O₂/N₂ and the δ¹⁸O record ratios for approximately the past 115,000 to 400,000 years in the Vostok ice core. They combined new measurements for O₂/N₂ and δ¹⁸O with data from Bender (2002) and Petit, et al. (1999), respectively.

Data are in Microsoft Excel format and are available via FTP.

This data set is a collection of analyses done on the the European Project for Ice Coring in Antarctica (EPICA)Dome C ice cores. The data include deuterium and other chemistry, insoluble dust, ice grain radius, dielectric profiling, electrical conductivity, and timescales.

EPICA has completed one core in the Dome Concordia region (Core EDC96, started in 1996, 788 m length). Drilling is ongoing on a second core EDC99 (started in 1999, reached a depth of 3200 m during the 2002/2003 field season. The ice at this depth is estimated to be about 700,000 years old.)

In January 1998, the collaborative ice-drilling project between Russia, the United States, and France at the Russian Vostok station in East Antarctica yielded the deepest ice core ever recovered, reaching a depth of 3,623 m (Petit et al. 1997, 1999). Ice cores are unique with their entrapped air inclusions enabling direct records of past changes in atmospheric trace-gas composition. Preliminary data indicate the Vostok ice-core record extends through four climate cycles, with ice slightly older than 400 kyr (Petit et al. 1997, 1999). Because air bubbles do not close at the surface of the ice sheet but only near the firn-ice transition (that is, at ~90 m below the surface at Vostok), the air extracted from the ice is younger than the surrounding ice (Barnola et al. 1991). Using semiempirical models of densification applied to past Vostok climate conditions, Barnola et al. (1991) reported that the age difference between air and ice may be ~6000 years during the coldest periods instead of ~4000 years, as previously assumed. Ice samples were cut with a bandsaw in a cold room (at about -15°C) as close as possible to the center of the core in order to avoid surface contamination (Barnola et al. 1983). Gas extraction and measurements were performed with the "Grenoble analytical setup," which involved crushing the ice sample (~40 g) under vacuum in a stainless steel container without melting it, expanding the gas released during the crushing in a pre-evacuated sampling loop, and analyzing the CO2 concentrations by gas chromatography (Barnola et al. 1983). The analytical system, except for the stainless steel container in which the ice was crushed, was calibrated for each ice sample measurement with a standard mixture of CO2 in nitrogen and oxygen. For further details on the experimental procedures and the dating of the successive ice layers at Vostok, see Barnola et al. (1987, 1991), Lorius et al. (1985), and Petit et al. (1999).

Data sources for the US ice core community maintained list of ice cores. This dataset is based on a US community recommendations for documenting Ice core metadata: e.g., Sites naming conventions, sampling (IGSN assignment), and data management. Attached files provided in MS Excel and CSV formats. We encourage the US ice core community to follow the following ice core borehole site naming standard: Abbreviated name of the ice core Hole (borehole or site) or trench: e.g., SPC (South Pole Core), WDC (West Antarctic Ice Sheet Divide ice core), SDM (Siple Dome Ice Core), AH (Allan Hills Blue Ice Area cores and trenches), MLT (Mt. Moulton Blue Ice Area Trench). Two-digit number representing the year when drilling/trenching started: e.g., 14 (2014), 06 (2006), 92 (1992) A letter for the ice core borehole ID: e.g., A for WDC-06A or WDC-05A In the provided template, the main ice core drilled from the South Pole (SPC) in 2014 is labeled: SPC-14-A Feel free to contact the authors if you have questions or a complex situation with multiple ice cores collected from the same borehole by different projects over a number of years.

This data set compares global atmospheric concentration of methane from ice cores taken on the ice sheets of Antarctica and Greenland. The data come from multiple ice cores on each continent, including Greenland Ice Core Project (GRIP) and Greenland Ice Sheet Project (GISP) ice cores and the Byrd and Vostok cores from Antarctica. (The orignal dataset is located at ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/synchronization/)

This document includes ice drill site information and ice core repository information for select ice cores retrieved between 1958 and 2022. Included data are not representative of all ice cores drilled during this time period, nor are they representative of all ice core samples collected and maintained by all of the contributing programs and facilities. Data are presented as they were provided by contributing facilities in 2022, when they were used to generate a figure for an article in Past Global Changes Magazine (doi.org/10.22498/pages.30.2.98).

The data describe ice core drilling sites (latitude, longitude, elevation, site name), ice core samples (bottom depth, bottom age, core diameter, core completion date, corresponding publications), and ice core storage facilities (latitude, longitude, name).

Contributing facilities include the following: Alfred Wegener Institute (Germany), Australian Antarctic Division (Australia), Australian Antarctic Program Partnership (Australia), Byrd Polar Center - University of Ohio (United States of America), Canadian Ice Core Lab (Canada), Chiba University (Japan), Commonwealth Scientific and Industrial Research Organization (Australia), Institute of Environmental Geosciences - University of Grenoble (France), Institute of Low Temperature Science - University of Hokkaido (Japan), Institute of Polar Science and Engineering - Jilin University (China), Karakoram International University (Pakistan), Lanzhou Institute of Glaciology and Geocryology (China), Nagoya University (Japan), National Institute of Polar Research (Japan), National Science Foundation Ice Core Facility (United States of America), New Zealand National Ice Core Facility (New Zealand, Physics of Ice Climate and Earth - University of Copenhagen (Denmark), Polar Research Institute of China (China), Research Institute for Humanity and Nature (Japan), and Tibet University.

We are grateful to each of these facilities for contributing details of their ice core collections for this work.

Electronic data accessibility and sample request procedures for a few of these facilities of which the authors are aware are listed below.

Australia: data can be obtained from the Australian Antarctic Data Centre (https://data.aad.gov.au); access to ice from the Australian Antarctic Program is via application (see https://www.antarctica.gov.au/science/information-for-scientists/)

Denmark: data can be obtained from www.iceandclimate.nbi.ku.dk/data; the ice sampling request procedure is listed here: https://www.iceandclimate.nbi.ku.dk/data/samplingprocedure/

United States: many ice core datasets can be found at the NOAA World Data Center (https://www.ncei.noaa.gov/products/paleoclimatology/ice-core); the allocation policy for ice core samples can be found here: https://icecores.org/policy.

This data set is part of the WAISCORES project, an NSF-funded project to understand the influence of the West Antarctic ice sheet on climate and sea level change. WAISCORES researchers acquired and analyzed ice cores from the Siple Dome, in the Siple Coast region, West Antarctica.

Lamorey measured the density of the shallow Siple Dome cores B - I. One-meter sections of the ice core were weighed on a balance beam in the field. The volume was determined by measuring the diameter and length of the core. The data consists of tab-delimited text files of density measurements and a sonic velocity profile, and a .gif format density-versus-depth plot. Data are available via FTP.

Ethane and acetylene are non-methane hydrocarbons released from combustion processes, with shared sources from fossil fuel use, biofuel and biomass burning. Ethane is also thought to have a source through natural geologic outgassing (Etiope and Ciccioli, 2009). Ethane and acetylene levels in the atmosphere can be used to quantify the variability in fossil fuel and biomass burning through time. In this project, paleo-atmospheric levels of ethane and acetylene were co-measured in the air bubbles of polar ice cores using a wet-extraction (melt) method (see Nicewonger et al., 2016 GRL (Geophysical Research Letters), Nicewonger et al., 2018 PNAS, or Nicewonger, 2019 PhD thesis). Ice core samples from Summit, Greenland (GISP2B, GISP2D), and West Antarctic Ice Sheet (WAIS) Divide, Antarctica (WDC05A, WDC06A) and South Pole, Antarctica (SPC14) were analyzed covering the last 2,000 years (~0 –1900 Common Era). The paleo-atmospheric ethane levels from this project allowed for the reconstruction of biomass burning ethane emissions over the last 1,000 years (see Nicewonger et al., 2018 PNAS publication). Please refer to the corresponding manuscript for more information on the “_Ethane.txt” data and how the gas ages were calculated (Nicewonger et al., 2018 PNAS SI Appendix). The ethane data have been since updated (Aug. 2019) with new analytical blank corrections, resulting in slightly different mixing ratios than what is reported in the Nicewonger et al., 2018 PNAS (Proceedings of the National Academy of Sciences) publication. Please use the updated dataset for future analysis ("site_EthaneAcetylene_2ky.txt") The acetylene levels measured may be impacted by solubility loss in the melt water during the wet-extraction method. The correction factor for this loss is about 1.15. Both solubility corrected and uncorrected data are available in the data sets. Missing or excluded data are denoted with -999.0.

This award supports a project to generate an absolute timescale for the Allan Hills Blue Ice Area (BIA), and then to reconstruct details of past climate changes and greenhouse gas concentrations for certain time periods back to 2.5 Ma. Ice ages will be determined by applying emerging methods for absolute and relative dating of trapped air bubbles (based on Argon-40/Argon-38, delta-18O of O2, and the O2/N2 ratio). To demonstrate the potential of the Allan Hills BIAs as a paleoclimate archive trenches and ice cores will be collected for age intervals corresponding to 110-140 ka, 1 Ma, and 2.5 Ma. During the proposed two field seasons a total of 6x100 m and additional 15 m cores will be combined with trenching. The intellectual merit of the proposed activity is that the results of this work will extend the landmark work of EPICA and other deep ice coring efforts, which give records dating back to 0.8 Ma, and will complement work planned by IPICS to drill a continuous Antarctic ice core extending to 1.5 Ma. The results will help to advance understanding of major climate regimes and transitions that took place between 0-2.5 Ma, including the 40 kyr world and the mid-Pleistocene climate transition. A major long-term scientific goal is to provide a transformative approach to the collection of paleoclimate records by establishing an "International Climate Park" in the Allan Hills BIA that would enable sampling of large quantities of known age ice as old as 2.5 Ma, by any interested American or foreign investigator. The broader impacts resulting from the proposed activity include training students who are well versed in advanced field, laboratory and numerical modeling methods combining geochemistry, glaciology, and paleoclimatology. We will include material relevant to our proposed research in our ongoing efforts in local education and in our outreach efforts for media. The University of Maine already has cyberinfrastructure, using state of the art web-based technology, which can provide a wide community of scientists with fast access to the results of our research. The work will contribute to the broad array of climate change studies that is informing worldwide understanding of natural and anthropogenic forced climate change, and the options for responding. This award has field work in Antarctica.

This archived Paleoclimatology Study is available from the NOAA National Centers for Environmental Information (NCEI), under the World Data Service (WDS) for Paleoclimatology. The associated NCEI study type is Ice Core. The data include parameters of ice cores with a geographic location of Canada. The time period coverage is from 59390 to -10 in calendar years before present (BP). See metadata information for parameter and study location details. Please cite this study when using the data.

The produced dataset (in MS Excel format) contains depth profile concentrations of a 16.5 m deep shallow core (covering approx. 200 years before present) drilled at the plateau site of Dome C, East Antarctica (75°06' South Latitude, 123°21' East Longitude), during the 23^rd Italian Antarctic Expedition.

The concentrations of the Polycyclic Aromatic Hydrocarbon (PAH) Benzo[k]fluoranthene (BKF) and of Organochlorinated Pesticides (OCP) expressed as three single compounds (PeCB, ALD and 44D) and total (Σ₅₁ Pesticides) are given in ng L^-1.

The ice core covers a time interval, which includes periods before and after the introduction of these Persistent Organic Pollutants (POPs) in commercial mixtures, as well as periods before the construction of research station facilities. However, in the top samples of the ice core, detected concentrations of analytes are ascribable to industrial anthropogenic activities.

This data set is comprised of optical images of ice core sections, acquired with a digital line-scan camera in the cold room facility at the U.S. National Ice Core Laboratory (NICL). Ice core sections are archival cuts which have rough-out rounds of ice with a single plane cut along one side. Ice sections were illuminated with fiber optic light guides connected to a 1000 watt (W) xenon light source. Original scan resolution varies from about 0.05 mm to 0.1 mm, and is documented in the metadata for each image. Images are in uncompressed Tagged Image File (.tif) form, with resolutions of 1.0 mm and 0.1 mm. Depth of image in the ice core is documented in the metadata files for each image. Data are available as .tif image files. Supporting information is available as ASCII text files (.txt), and other file formats readable with a freely available image processing program, IceImageJ. (Dataset was transferred from NSIDC without much metadata information)