In:
Climate of the Past, Copernicus GmbH, Vol. 15, No. 2 ( 2019-04-10), p. 751-779
Abstract:
Abstract. We present a 2700-year annually resolved chronology and snow accumulation
history for the Roosevelt Island Climate Evolution (RICE) ice core, Ross Ice
Shelf, West Antarctica. The core adds information on past accumulation
changes in an otherwise poorly constrained sector of Antarctica. The timescale was constructed by identifying annual cycles in
high-resolution impurity records, and it constitutes the top part of the
Roosevelt Island Ice Core Chronology 2017 (RICE17). Validation by volcanic
and methane matching to the WD2014 chronology from the WAIS Divide ice core
shows that the two timescales are in excellent agreement. In a companion
paper, gas matching to WAIS Divide is used to extend the timescale for the
deeper part of the core in which annual layers cannot be identified. Based on the annually resolved timescale, we produced a record of past snow
accumulation at Roosevelt Island. The accumulation history shows that
Roosevelt Island experienced slightly increasing accumulation rates between
700 BCE and 1300 CE, with an average accumulation of 0.25±0.02 m
water equivalent (w.e.) per year. Since 1300 CE, trends in the accumulation
rate have been consistently negative, with an acceleration in the rate of
decline after the mid-17th century. The current accumulation rate at
Roosevelt Island is 0.210±0.002 m w.e. yr−1 (average since 1965 CE, ±2σ), and it is rapidly declining with a trend corresponding to
0.8 mm yr−2. The decline observed since the mid-1960s is 8 times faster
than the long-term decreasing trend taking place over the previous
centuries, with decadal mean accumulation rates consistently being below
average. Previous research has shown a strong link between Roosevelt Island
accumulation rates and the location and intensity of the Amundsen Sea Low,
which has a significant impact on regional sea-ice extent. The decrease in
accumulation rates at Roosevelt Island may therefore be explained in terms
of a recent strengthening of the ASL and the expansion of sea ice in the eastern
Ross Sea. The start of the rapid decrease in RICE accumulation rates
observed in 1965 CE may thus mark the onset of significant increases in
regional sea-ice extent.
Type of Medium:
Online Resource
ISSN:
1814-9332
DOI:
10.5194/cp-15-751-2019
DOI:
10.5194/cp-15-751-2019-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2217985-9
