Stable water isotopes and accumulation rates in the Union Glacier region, Ellsworth Mountains, West Antarctica, over the last 35 years
Journal
The Cryosphere
ISSN
1994-0424
Date Issued
2020
Author(s)
Kirstin Hoffmann
Francisco Fernandoy
Hanno Meyer
Elizabeth R. Thomas
Marcelo Aliaga
Dieter Tetzner
Johannes Freitag
Thomas Opel
Jorge Arigony-Neto
Christian Florian Göbel
Ricardo Jaña
Rodríguez Oroz, María Delia
Rebecca Tuckwell
Emily Ludlow
Joseph R. McConnell
Christoph Schneider
Type
Resource Types::text::journal::journal article
Abstract
<jats:p>Abstract. Antarctica is well known to be highly susceptible to atmospheric and oceanic
warming. However, due to the lack of long-term and in situ meteorological
observations, little is known about the magnitude of the warming and the
meteorological conditions in the intersection region between the Antarctic
Peninsula (AP), the West Antarctic Ice Sheet (WAIS) and the East Antarctic
Ice Sheet (EAIS). Here we present new stable water isotope data (δ18O, δD, d excess) and accumulation rates from firn cores in the Union Glacier (UG) region, located in the Ellsworth Mountains at the
northern edge of the WAIS. The firn core stable oxygen isotopes and the d excess exhibit no statistically significant trend for the period 1980–2014, suggesting that regional changes in near-surface air temperature and
moisture source variability have been small during the last 35 years.
Backward trajectory modelling revealed the Weddell Sea sector, Coats Land
and Dronning Maud Land (DML) to be the main moisture source regions for the study site throughout
the year. We found that mean annual δ18O (δD) values
in the UG region are negatively correlated with sea ice concentrations (SICs) in the northern Weddell Sea but not influenced by large-scale modes of
climate variability such as the Southern Annular Mode (SAM) and the El
Niño–Southern Oscillation (ENSO). Only mean annual d-excess values show a weak positive correlation with the SAM. On average annual snow accumulation in the UG region amounts to 0.245 m w.e. a−1 in 1980–2014 and has slightly decreased during this period. It
is only weakly related to sea ice conditions in the Weddell Sea sector and
not correlated with SAM and ENSO. We conclude that neither the rapid warming nor the large increases in snow
accumulation observed on the AP and in West Antarctica during the last
decades have extended inland to the Ellsworth Mountains. Hence, the UG
region, although located at the northern edge of the WAIS and relatively
close to the AP, exhibits rather stable climate characteristics similar to
those observed in East Antarctica.
</jats:p>
warming. However, due to the lack of long-term and in situ meteorological
observations, little is known about the magnitude of the warming and the
meteorological conditions in the intersection region between the Antarctic
Peninsula (AP), the West Antarctic Ice Sheet (WAIS) and the East Antarctic
Ice Sheet (EAIS). Here we present new stable water isotope data (δ18O, δD, d excess) and accumulation rates from firn cores in the Union Glacier (UG) region, located in the Ellsworth Mountains at the
northern edge of the WAIS. The firn core stable oxygen isotopes and the d excess exhibit no statistically significant trend for the period 1980–2014, suggesting that regional changes in near-surface air temperature and
moisture source variability have been small during the last 35 years.
Backward trajectory modelling revealed the Weddell Sea sector, Coats Land
and Dronning Maud Land (DML) to be the main moisture source regions for the study site throughout
the year. We found that mean annual δ18O (δD) values
in the UG region are negatively correlated with sea ice concentrations (SICs) in the northern Weddell Sea but not influenced by large-scale modes of
climate variability such as the Southern Annular Mode (SAM) and the El
Niño–Southern Oscillation (ENSO). Only mean annual d-excess values show a weak positive correlation with the SAM. On average annual snow accumulation in the UG region amounts to 0.245 m w.e. a−1 in 1980–2014 and has slightly decreased during this period. It
is only weakly related to sea ice conditions in the Weddell Sea sector and
not correlated with SAM and ENSO. We conclude that neither the rapid warming nor the large increases in snow
accumulation observed on the AP and in West Antarctica during the last
decades have extended inland to the Ellsworth Mountains. Hence, the UG
region, although located at the northern edge of the WAIS and relatively
close to the AP, exhibits rather stable climate characteristics similar to
those observed in East Antarctica.
</jats:p>
Subjects
antarctic ice sheet
;
antarctic peninsula
;
antarctica
;
antarctica
;
east antarctic ice sheet
;
east antarctica
;
ellsworth mountains
;
queen maud land
;
southern ocean
;
union glacier
;
weddell sea
;
west antarctic ice sheet
;
west antarctica
;
air temperature
;
hydrogen isotope
;
meteorology
;
sea ice
;
snow accumulation
;
snow cover
;
stable isotope