High-resolution ice cores from US ITASE (West Antarctica): development and validation of chronologies and determination of precision and accuracy

Abstract Shallow ice cores were obtained from widely distributed sites across the West Antarctic ice sheet, as part of the United States portion of the International Trans-Antarctic Scientific Expedition (US ITASE) program. The US ITASE cores have been dated by annual-layer counting, primarily through the identification of summer peaks in non-sea-salt sulfate (nssSO4 2–) concentration. Absolute dating accuracy of better than 2 years and relative dating accuracy better than 1 year is demonstrated by the identification of multiple volcanic marker horizons in each of the cores, Tambora, Indonesia (1815), being the most prominent. Independent validation is provided by the tracing of isochronal layers from site to site using high-frequency ice-penetrating radar observations, and by the timing of mid-winter warming events in stable-isotope ratios, which demonstrate significantly better than 1 year accuracy in the last 20 years. Dating precision to ±1 month is demonstrated by the occurrence of summer nitrate peaks and stable-isotope ratios in phase with nssSO4 2–, and winter-time sea-salt peaks out of phase, with phase variation of <1 month. Dating precision and accuracy are uniform with depth, for at least the last 100 years.

[1]  O. Schrems,et al.  Variability of tropospheric hydroperoxides at a coastal surface site in Antarctica , 2000 .

[2]  R. Delmas.  Antarctic sulphate budget , 1982, Nature.

[3]  E. Wolff,et al.  Evidence for winter/spring denitrification of the stratosphere in the nitrate record of Antarctic firn cores , 1993 .

[4]  D. Vaughan,et al.  Reassessment of net surface mass balance in Antarctica , 1999 .

[5]  D. Dixon,et al.  Climate variability in West Antarctica derived from annual accumulation-rate records from ITASE firn/ice cores , 2004, Annals of Glaciology.

[6]  Steven A. Arcone,et al.  Phase structure of radar stratigraphic horizons within Antarctic firn , 2005, Annals of Glaciology.

[7]  J. Comiso,et al.  Recent Climate Variability in Antarctica from Satellite-Derived Temperature Data , 2004 .

[8]  M. Frey,et al.  Climate sensitivity of the century-scale hydrogen peroxide (H2O2) record preserved in 23 ice cores from West Antarctica , 2006 .

[9]  Malcolm K. Hughes,et al.  Global-scale temperature patterns and climate forcing over the past six centuries , 1998, Nature.

[10]  Steven A. Arcone,et al.  Variability in accumulation rates from GPR profiling on the West Antarctic plateau , 2004, Annals of Glaciology.

[11]  D. Etheridge,et al.  Recent southern Indian Ocean climate variability inferred from a Law Dome ice core: new insights for the interpretation of coastal Antarctic isotopic records , 2003 .

[12]  D. Schneider,et al.  Spatial and temporal variability of Antarctic ice sheet microwave brightness temperatures , 2002 .

[13]  R. Röthlisberger,et al.  Technique for continuous high-resolution analysis of trace substances in firn and ice cores , 2000 .

[14]  D. H. Robinson,et al.  Phytoplankton community structure and the drawdown of nutrients and CO2 in the southern ocean , 1999, Science.

[15]  P. Mayewski,et al.  Complexity of Holocene Climate as Reconstructed from a Greenland Ice Core , 1995, Science.

[16]  P. Mayewski,et al.  The effect of spatial and temporal accumulation rate variability in west Antarctica on soluble ion deposition , 2000 .

[17]  P. Mayewski,et al.  Relationship between continuous aerosol measurements and firn core chemistry over a 10‐year period at the South Pole , 1998 .

[18]  P. Mayewski,et al.  Glaciochemistry of polar ice cores: A review , 1997 .

[19]  Xiaojun Yuan,et al.  The Antarctic dipole and its predictability , 2001 .

[20]  P. Mayewski,et al.  Determination of major ions in snow and ice cores by ion chromatography , 1992 .

[21]  D. Dixon,et al.  A 200 year sub-annual record of sulfate in West Antarctica, from 16 ice cores , 2004, Annals of Glaciology.

[22]  R. Alley,et al.  Dating the Siple Dome (Antarctica) ice core by manual and computer interpretation of annual layering , 2004, Journal of Glaciology.

[23]  J. Jouzel,et al.  Homogeneous climate variability across East Antarctica over the past three glacial cycles , 2003, Nature.

[24]  J. Wallace,et al.  Annular Modes in the Extratropical Circulation. Part I: Month-to-Month Variability* , 2000 .

[25]  A. Walden,et al.  Spectral analysis for physical applications : multitaper and conventional univariate techniques , 1996 .

[26]  D. Thomson,et al.  Spectrum estimation and harmonic analysis , 1982, Proceedings of the IEEE.

[27]  P. Mayewski,et al.  A comparison of major chemical species seasonal concentration and accumulation at the South Pole and summit, Greenland , 1992 .

[28]  S. Pawson,et al.  Persistence of the lower stratospheric polar vortices , 1999 .

[29]  D. Schneider,et al.  Glaciological and climatic significance of Hercules Dome, Antarctica: An optimal site for deep ice core drilling , 2005 .

[30]  U. Rick,et al.  Microstructure and permeability in the near-surface firn near a potential US deep-drilling site in West Antarctica , 2004, Annals of Glaciology.

[31]  P. Mayewski,et al.  Sea level pressure variability in the Amundsen Sea region inferred from a West Antarctic glaciochemical record , 2000 .

[32]  D. Schneider,et al.  High-resolution ice-core stable-isotopic records from Antarctica: towards interannual climate reconstruction , 2005, Annals of Glaciology.

[33]  Sridhar Anandakrishnan,et al.  An empirical technique for estimating near-surface air temperature trends in central Greenland from SSM/I brightness temperatures , 1995 .

[34]  P. Mayewski,et al.  A 700 year record of Southern Hemisphere extratropical climate variability , 2004, Annals of Glaciology.

[35]  P. Mayewski,et al.  Recent increase in nitrate concentration of Antarctic snow , 1990, Nature.

[36]  A J Gow,et al.  Record of Volcanism Since 7000 B.C. from the GISP2 Greenland Ice Core and Implications for the Volcano-Climate System , 1994, Science.

[37]  J. Jouzel,et al.  A new 27 ky high resolution East Antarctic climate record , 2001 .

[38]  G. Fiocco,et al.  Volcanic aerosol layers observed by lidar at South Pole, September 1991–June 1992 , 1993 .

[39]  M. Widmann,et al.  Instrument- and Tree-Ring-Based Estimates of the Antarctic Oscillation , 2003 .

[40]  D. Dixon,et al.  Sources and transport pathways of marine aerosol species into West Antarctica , 2005, Annals of Glaciology.

[41]  E. Mosley‐Thompson,et al.  Little Ice Age (Neoglacial) Paleoenvironmental Conditions At Siple Station, Antarctica , 1990, Annals of Glaciology.

[42]  Michael E. Mann,et al.  Global surface temperatures over the past two millennia , 2003 .

[43]  J. McConnell,et al.  Physically based modeling of atmosphere‐to‐snow‐to‐firn transfer of H2O2 at South Pole , 1998 .

[44]  A. Minikin,et al.  Sea‐salt aerosol in coastal Antarctic regions , 1998 .

[45]  M. Chenoweth.  Two major volcanic cooling episodes derived from global marine air temperature, AD 1807–1827 , 2001 .

[46]  John B. Anderson,et al.  Changes in Antarctic stratospheric aerosol characteristics due to volcanic eruptions as monitored by the Stratospheric Aerosol and Gas Experiment II satellite , 1995 .

[47]  E. Steig,et al.  Isotopic diffusion in polar firn: implications for interpretation of seasonal climate parameters in ice-core records, with emphasis on central Greenland , 1998, Journal of Glaciology.

[48]  W. Dansgaard,et al.  Oxygen Isotope Profiles through the Antarctic and Greenland Ice Sheets , 1972, Nature.

[49]  P. Mayewski,et al.  Spatial variability of Antarctic surface snow glaciochemistry: implications for palaeoatmospheric circulation reconstructions , 1999, Antarctic Science.

[50]  D. Bromwich,et al.  Modeled Antarctic Precipitation. Part I: Spatial and Temporal Variability* , 2004 .

[51]  J. Severinghaus,et al.  Abrupt climate change around 22 ka on the Siple Coast of Antarctica. , 2004 .

[52]  P. Mayewski,et al.  International Trans Antarctic Scientific Expedition (ITASE) , 2006 .

[53]  E. Mosley‐Thompson,et al.  Little ice age (neoglacial) paleoenvironmental conditions at siple station , 1990 .

[54]  W. Sturges,et al.  Seasonality of reactive nitrogen oxides (NOy) at Neumayer Station, Antarctica , 2002 .

[55]  Giacomo R. DiTullio,et al.  A global database of sea surface dimethylsulfide (DMS) measurements and a procedure to predict sea surface DMS as a function of latitude, longitude, and month , 1999 .