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Seasonal-Scale Dating of a Shallow Ice Core From Greenland Using Oxygen Isotope Matching Between Data and Simulation

Furukawa, Ryoto; Uemura, Ryu; Fujita, Koji; Sjolte, Jesper LU ; Yoshimura, Kei; Matoba, Sumito and Iizuka, Yoshinori (2017) In Journal of Geophysical Research: Space Physics
Abstract

A precise age scale based on annual layer counting is essential for investigating past environmental changes from ice core records. However, subannual scale dating is hampered by the irregular intraannual variabilities of oxygen isotope (δ18O) records. Here we propose a dating method based on matching the δ18O variations between ice core records and records simulated by isotope-enabled climate models. We applied this method to a new δ18O record from an ice core obtained from a dome site in southeast Greenland. The close similarity between the δ18O records from the ice core and models enables correlation and the production of a precise age scale, with an accuracy of a few months. A missing... (More)

A precise age scale based on annual layer counting is essential for investigating past environmental changes from ice core records. However, subannual scale dating is hampered by the irregular intraannual variabilities of oxygen isotope (δ18O) records. Here we propose a dating method based on matching the δ18O variations between ice core records and records simulated by isotope-enabled climate models. We applied this method to a new δ18O record from an ice core obtained from a dome site in southeast Greenland. The close similarity between the δ18O records from the ice core and models enables correlation and the production of a precise age scale, with an accuracy of a few months. A missing δ18O minimum in the 1995/1996 winter is an example of an indistinct δ18O seasonal cycle. Our analysis suggests that the missing δ18O minimum is likely caused by a combination of warm air temperature, weak moisture transport, and cool ocean temperature. Based on the age scale, the average accumulation rate from 1960 to 2014 is reconstructed as 1.02 m yr-1 in water equivalent. The annual accumulation rate shows an increasing trend with a slope of 3.6 mm yr-1, which is mainly caused by the increase in the autumn accumulation rate of 2.6 mm yr-1. This increase is likely linked to the enhanced hydrological cycle caused by the decrease in Arctic sea ice area. Unlike the strong seasonality of precipitation amount in the ERA reanalysis data in the southeast dome region, our reconstructed accumulation rate suggests a weak seasonality.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Accumulation, ERA, GCM, Greenland, Isotope, Sea ice
in
Journal of Geophysical Research: Space Physics
external identifiers
  • scopus:85032382529
ISSN
2169-897X
DOI
10.1002/2017JD026716
language
English
LU publication?
yes
id
0471f950-ff37-41e1-a8f3-92b402799d7c
date added to LUP
2017-11-08 12:37:42
date last changed
2018-01-21 04:25:42
@article{0471f950-ff37-41e1-a8f3-92b402799d7c,
  abstract     = {<p>A precise age scale based on annual layer counting is essential for investigating past environmental changes from ice core records. However, subannual scale dating is hampered by the irregular intraannual variabilities of oxygen isotope (δ<sup>18</sup>O) records. Here we propose a dating method based on matching the δ<sup>18</sup>O variations between ice core records and records simulated by isotope-enabled climate models. We applied this method to a new δ<sup>18</sup>O record from an ice core obtained from a dome site in southeast Greenland. The close similarity between the δ<sup>18</sup>O records from the ice core and models enables correlation and the production of a precise age scale, with an accuracy of a few months. A missing δ<sup>18</sup>O minimum in the 1995/1996 winter is an example of an indistinct δ<sup>18</sup>O seasonal cycle. Our analysis suggests that the missing δ<sup>18</sup>O minimum is likely caused by a combination of warm air temperature, weak moisture transport, and cool ocean temperature. Based on the age scale, the average accumulation rate from 1960 to 2014 is reconstructed as 1.02 m yr<sup>-1</sup> in water equivalent. The annual accumulation rate shows an increasing trend with a slope of 3.6 mm yr<sup>-1</sup>, which is mainly caused by the increase in the autumn accumulation rate of 2.6 mm yr<sup>-1</sup>. This increase is likely linked to the enhanced hydrological cycle caused by the decrease in Arctic sea ice area. Unlike the strong seasonality of precipitation amount in the ERA reanalysis data in the southeast dome region, our reconstructed accumulation rate suggests a weak seasonality.</p>},
  author       = {Furukawa, Ryoto and Uemura, Ryu and Fujita, Koji and Sjolte, Jesper and Yoshimura, Kei and Matoba, Sumito and Iizuka, Yoshinori},
  issn         = {2169-897X},
  keyword      = {Accumulation,ERA,GCM,Greenland,Isotope,Sea ice},
  language     = {eng},
  month        = {10},
  series       = {Journal of Geophysical Research: Space Physics},
  title        = {Seasonal-Scale Dating of a Shallow Ice Core From Greenland Using Oxygen Isotope Matching Between Data and Simulation},
  url          = {http://dx.doi.org/10.1002/2017JD026716},
  year         = {2017},
}