State of Balance of the Ice Sheet in the Antarctic Peninsula

1982 ◽  
Vol 3 ◽  
pp. 77-82 ◽  
Author(s):  
Christopher S. M. Doake
Keyword(s):  
Antarctic Peninsula ◽  
East Coast ◽  
Accumulation Rate ◽  
Level Line ◽  
Ice Shelf ◽  
High Accumulation ◽  
Glacier Recession ◽  
Valley Glacier ◽  
The Antarctic ◽  
Small Valley

Data from ice rises on the east coast of the Antarctic Peninsula can be interpreted as showing that the ice is thinning at rates of up 0.5 m a−1. However, a level line between two nunataks in Palmer Land showed no change in surface elevation over a period of 5 a. Melt rates on George VI Ice Shelf vary with position and may indicate that parts of the ice shelf are thickening at the rate of several m a−1, presumably in response to a higher accumulation rate over the peninsula a few hundred years ago. A small valley glacier, Spartan Glacier, is wasting away at about 0.27 m a−1. Ice fronts on both east and west coasts of the peninsula have been retreating for the last 30 a. It seems that there is general glacier recession in response to a wanner climate and decreased snowfall for at least the last 30 a, while parts of the peninsula are still thickening in response to a high accumulation rate several hundred years ago.

scholarly journals State of Balance of the Ice Sheet in the Antarctic Peninsula

1982 ◽  
Vol 3 ◽  
pp. 77-82 ◽  
Author(s):  
Christopher S. M. Doake
Keyword(s):  
Antarctic Peninsula ◽  
East Coast ◽  
Accumulation Rate ◽  
Level Line ◽  
Ice Shelf ◽  
High Accumulation ◽  
Glacier Recession ◽  
Valley Glacier ◽  
The Antarctic ◽  
Small Valley

Data from ice rises on the east coast of the Antarctic Peninsula can be interpreted as showing that the ice is thinning at rates of up 0.5 m a−1. However, a level line between two nunataks in Palmer Land showed no change in surface elevation over a period of 5 a. Melt rates on George VI Ice Shelf vary with position and may indicate that parts of the ice shelf are thickening at the rate of several m a−1, presumably in response to a higher accumulation rate over the peninsula a few hundred years ago. A small valley glacier, Spartan Glacier, is wasting away at about 0.27 m a−1. Ice fronts on both east and west coasts of the peninsula have been retreating for the last 30 a. It seems that there is general glacier recession in response to a wanner climate and decreased snowfall for at least the last 30 a, while parts of the peninsula are still thickening in response to a high accumulation rate several hundred years ago.

scholarly journals A synthesis of remote sensing data on Wilkins Ice Shelf, Antarctica

1993 ◽  
Vol 17 ◽  
pp. 211-218 ◽  
Author(s):  
D.G. Vaughan ◽  
D.R. Mantripp ◽  
J. Sievers ◽  
C.S.M. Doake
Keyword(s):  
Mass Balance ◽  
Antarctic Peninsula ◽  
Accumulation Rate ◽  
Remote Sensing Data ◽  
Dynamic Effect ◽  
Remotely Sensed Data ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Limit Of Viability ◽  
The Antarctic

Wilkins Ice Shelf has an area of 16000 km2 and lies off the west coast of the Antarctic Peninsula bounded by Alexander, Latady, Charcot and Rothschild islands. Several ice shelves, including Wilkins, exist close to a climatic limit of viability. The recent disintegration of the neighbouring Wordie Ice Shelf has been linked to atmopsheric warming observed on the Antarctic Peninsula. The limit of ice-shelf viability thus appears to have migrated south. Should this continue, the question arises; how long will Wilkins Ice Shelf survive?Compared with the other ice shelves on the Antarctic Peninsula, few surface glaciological data have been collected on Wilkins Ice Shelf. We compare, contrast and combine a variety of remotely sensed data: the recently declassified GEOSAT Geodetic Mission altimetry, Landsat MSS and TM imagery, and radio-echo sounding data (RES), to study its structure and mass balance regime.We find that this shelf has an unusual mass balance regime and relies heavily for sustenance on in situ accumulation. Its response to a continued atmospheric warming may be significantly different from that of Wordie Ice Shelf. Wordie Ice Shelf was fed by several dynamic outlet glaciers which accelerated the disintegration process when the ice shelf fractured. Wilkins Ice Shelf by contrast is almost stagnant and is expected to respond by normal calving at the ice front. Changes in the accumulation rate or basal melt-rate may, however, dominate any dynamic effect. Over the last two decades the ice front positions have remained stable.

scholarly journals A synthesis of remote sensing data on Wilkins Ice Shelf, Antarctica

1993 ◽  
Vol 17 ◽  
pp. 211-218 ◽  
Author(s):  
D.G. Vaughan ◽  
D.R. Mantripp ◽  
J. Sievers ◽  
C.S.M. Doake
Keyword(s):  
Mass Balance ◽  
Antarctic Peninsula ◽  
Accumulation Rate ◽  
Remote Sensing Data ◽  
Dynamic Effect ◽  
Remotely Sensed Data ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Limit Of Viability ◽  
The Antarctic

Wilkins Ice Shelf has an area of 16000 km2 and lies off the west coast of the Antarctic Peninsula bounded by Alexander, Latady, Charcot and Rothschild islands. Several ice shelves, including Wilkins, exist close to a climatic limit of viability. The recent disintegration of the neighbouring Wordie Ice Shelf has been linked to atmopsheric warming observed on the Antarctic Peninsula. The limit of ice-shelf viability thus appears to have migrated south. Should this continue, the question arises; how long will Wilkins Ice Shelf survive? Compared with the other ice shelves on the Antarctic Peninsula, few surface glaciological data have been collected on Wilkins Ice Shelf. We compare, contrast and combine a variety of remotely sensed data: the recently declassified GEOSAT Geodetic Mission altimetry, Landsat MSS and TM imagery, and radio-echo sounding data (RES), to study its structure and mass balance regime. We find that this shelf has an unusual mass balance regime and relies heavily for sustenance on in situ accumulation. Its response to a continued atmospheric warming may be significantly different from that of Wordie Ice Shelf. Wordie Ice Shelf was fed by several dynamic outlet glaciers which accelerated the disintegration process when the ice shelf fractured. Wilkins Ice Shelf by contrast is almost stagnant and is expected to respond by normal calving at the ice front. Changes in the accumulation rate or basal melt-rate may, however, dominate any dynamic effect. Over the last two decades the ice front positions have remained stable.

scholarly journals A new glacier inventory for 2009 reveals spatial and temporal variability in glacier response to atmospheric warming in the Northern Antarctic Peninsula, 1988–2009

2011 ◽  
Vol 5 (6) ◽  
pp. 3541-3595 ◽  
Author(s):  
B. J. Davies ◽  
J. L. Carrivick ◽  
N. F. Glasser ◽  
M. J. Hambrey ◽  
J. L. Smellie
Keyword(s):  
Antarctic Peninsula ◽  
Slope Aspect ◽  
Published Data ◽  
Ice Shelf ◽  
Tidewater Glaciers ◽  
Eastern Side ◽  
Glacier Recession ◽  
Recession Rates ◽  
James Ross Island ◽  
The Antarctic

Abstract. The Northern Antarctic Peninsula has recently exhibited ice-shelf disintegration, glacier recession and acceleration. However, the dynamic response of land-terminating, ice-shelf tributary and tidewater glaciers has not yet been quantified or assessed for variability, and there are sparse published data for glacier classification, morphology, area, length or altitude. This paper firstly uses ASTER images from 2009 and a SPIRIT DEM from 2006 to classify the area, length, altitude, slope, aspect, geomorphology, type and hypsometry of 194 glaciers on Trinity Peninsula, Vega Island and James Ross Island. Secondly, this paper uses LANDSAT-4 and ASTER images from 1988 and 2001 and data from the Antarctic Digital Database (ADD) from 1997 to document glacier change 1988–2009. From 1988–2001, 90 % of glaciers receded, and from 2001–2009, 79 % receded. Glaciers on the western side of Trinity Peninsula retreated relatively little. On the eastern side of Trinity Peninsula, the rate of recession of ice-shelf tributary glaciers has slowed from 12.9 km2 a−1 (1988–2001) to 2.4 km2 a−1 (2001–2009). Tidewater glaciers on the drier, cooler Eastern Trinity Peninsula experienced fastest recession from 1988–2001, with limited frontal retreat after 2001. Land-terminating glaciers on James Ross Island also retreated fastest in the period 1988–2001. Large tidewater glaciers on James Ross Island are now declining in areal extent at rates of up to 0.04 km2 a−1. This east-west difference is largely a result of orographic temperature and precipitation gradients across the Antarctic Peninsula. Strong variability in tidewater glacier recession rates may result from the influence of glacier length, altitude, slope and hypsometry on glacier mass balance. High snowfall means that the glaciers on the Western Peninsula are not currently rapidly receding. Recession rates on the eastern side of Trinity Peninsula are slowing as the floating ice tongues retreat into the fjords and the glaciers reach a new dynamic equilibrium. The rapid glacier recession of tidewater glaciers on James Ross Island is likely to continue because of their low elevations and flat profiles. In contrast, the higher and steeper tidewater glaciers on the Eastern Antarctic Peninsula will attain more stable frontal positions after low-lying ablation areas are removed.

scholarly journals Reconstruction of annual accumulation rate on firn, synchronising H<sub>2</sub>O<sub>2</sub> concentration data with an estimated temperature record

2021 ◽  
Vol 15 (7) ◽  
pp. 3495-3505
Author(s):  
Jandyr M. Travassos ◽  
Saulo S. Martins ◽  
Mariusz Potocki ◽  
Jefferson C. Simões
Keyword(s):  
Antarctic Peninsula ◽  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Data Series ◽  
Temperature Record ◽  
Concentration Data ◽  
High Accumulation ◽  
Operational Life ◽  
The Antarctic

Abstract. This work deals with reconstructing firn layer thicknesses at the deposition time from the firn's observed thickness in ice cores, thus reconstructing the annual accumulation, yielding a timescale and an ice-core chronology. We employed a dynamic time warping algorithm to find an optimal, non-linear alignment between an H2O2 concentration data series from 98 m worth of ice cores of a borehole on the central ice divide of the Detroit Plateau, the Antarctic Peninsula, and an estimated local temperature time series. The viability and the physical reliability of the procedure are rooted in the robustness of the seasonal marker H2O2 in a high-accumulation context, which brought the entire borehole to within the operational life span of four Antarctic stations around the Antarctic Peninsula. The process was heavily based on numerical optimisation, producing a mathematically sound match between the two series to estimate the annual layering efficiently on the entire data section at once, being disposition-free. The results herein confirm a high annual accumulation rate of aN=2.8 m w.e./yr, which is of the same order of magnitude as and highly correlated with that of the Bruce Plateau and twice as large as that of the Gomez Plateau, 300 and 1200 km further south, respectively.

scholarly journals Recent ice-surface-elevation changes of Fleming Glacier in response to the removal of the Wordie Ice Shelf, Antarctic Peninsula

2010 ◽  
Vol 51 (55) ◽  
pp. 97-102 ◽  
Author(s):  
J. Wendt ◽  
A. Rivera ◽  
A. Wendt ◽  
F. Bown ◽  
R. Zamora ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Regional Climate ◽  
Airborne Lidar ◽  
Similar Data ◽  
Ice Shelf ◽  
International Polar Year ◽  
Ice Flow ◽  
Ice Shelves ◽  
Elevation Changes ◽  
The Antarctic

AbstractRegional climate warming has caused several ice shelves on the Antarctic Peninsula to retreat and ultimately collapse during recent decades. Glaciers flowing into these retreating ice shelves have responded with accelerating ice flow and thinning. The Wordie Ice Shelf on the west coast of the Antarctic Peninsula was reported to have undergone a major areal reduction before 1989. Since then, this ice shelf has continued to retreat and now very little floating ice remains. Little information is currently available regarding the dynamic response of the glaciers feeding the Wordie Ice Shelf, but we describe a Chilean International Polar Year project, initiated in 2007, targeted at studying the glacier dynamics in this area and their relationship to local meteorological conditions. Various data were collected during field campaigns to Fleming Glacier in the austral summers of 2007/08 and 2008/09. In situ measurements of ice-flow velocity first made in 1974 were repeated and these confirm satellite-based assessments that velocity on the glacier has increased by 40–50% since 1974. Airborne lidar data collected in December 2008 can be compared with similar data collected in 2004 in collaboration with NASA and the Chilean Navy. This comparison indicates continued thinning of the glacier, with increasing rates of thinning downstream, with a mean of 4.1 ± 0.2 m a−1 at the grounding line of the glacier. These comparisons give little indication that the glacier is achieving a new equilibrium.

scholarly journals Speedup and fracturing of George VI Ice Shelf, Antarctic Peninsula

2013 ◽  
Vol 7 (3) ◽  
pp. 797-816 ◽  
Author(s):  
T. O. Holt ◽  
N. F. Glasser ◽  
D. J. Quincey ◽  
M. R. Siegfried
Keyword(s):  
Antarctic Peninsula ◽  
Structural Changes ◽  
Surface Elevation ◽  
Ice Shelf ◽  
Ice Shelves ◽  
The North ◽  
Surface Elevation Change ◽  
Elevation Changes ◽  
Negative Surface ◽  
The Antarctic

Abstract. George VI Ice Shelf (GVIIS) is located on the Antarctic Peninsula, a region where several ice shelves have undergone rapid breakup in response to atmospheric and oceanic warming. We use a combination of optical (Landsat), radar (ERS 1/2 SAR) and laser altimetry (GLAS) datasets to examine the response of GVIIS to environmental change and to offer an assessment on its future stability. The spatial and structural changes of GVIIS (ca. 1973 to ca. 2010) are mapped and surface velocities are calculated at different time periods (InSAR and optical feature tracking from 1989 to 2009) to document changes in the ice shelf's flow regime. Surface elevation changes are recorded between 2003 and 2008 using repeat track ICESat acquisitions. We note an increase in fracture extent and distribution at the south ice front, ice-shelf acceleration towards both the north and south ice fronts and spatially varied negative surface elevation change throughout, with greater variations observed towards the central and southern regions of the ice shelf. We propose that whilst GVIIS is in no imminent danger of collapse, it is vulnerable to ongoing atmospheric and oceanic warming and is more susceptible to breakup along its southern margin in ice preconditioned for further retreat.

scholarly journals Speedup and fracturing of George VI Ice Shelf, Antarctic Peninsula

2013 ◽  
Vol 7 (1) ◽  
pp. 373-417 ◽  
Author(s):  
T. O. Holt ◽  
N. F. Glasser ◽  
D. J. Quincey ◽  
M. R. Siegfried
Keyword(s):  
Antarctic Peninsula ◽  
Structural Changes ◽  
Surface Elevation ◽  
Ice Shelf ◽  
Ice Shelves ◽  
The North ◽  
Surface Elevation Change ◽  
Elevation Changes ◽  
Negative Surface ◽  
The Antarctic

Abstract. George VI Ice Shelf (GVIIS) is located on the Antarctic Peninsula, a region where several ice shelves have undergone rapid breakup in response to atmospheric and oceanic warming. We use a combination of optical (Landsat), radar (ERS 1/2 SAR) and laser altimetry (GLAS) datasets to examine the response of GVIIS to environmental change and to offer an assessment on its future stability. The spatial and structural changes of GVIIS (ca. 1973 to ca. 2010) are mapped and surface velocities are calculated at different time periods (InSAR and optical feature tracking from 1989 to 2009) to document changes in the ice shelf's flow regime. Surface elevation changes are recorded between 2003 and 2008 using repeat track ICESat acquisitions. We note an increase in fracture extent and distribution at the south ice front, ice-shelf acceleration towards both the north and south ice fronts and spatially varied negative surface elevation change throughout, with greater variations observed towards the central and southern regions of the ice shelf. We propose that whilst GVIIS is in no imminent danger of collapse, it is vulnerable to on-going atmospheric and oceanic warming and is more susceptible to breakup along its southern margin in ice preconditioned for further retreat.

scholarly journals Downslope föhn winds over the Antarctic Peninsula and their effect on the Larsen ice shelves

2014 ◽  
Vol 14 (18) ◽  
pp. 9481-9509 ◽  
Author(s):  
D. P. Grosvenor ◽  
J. C. King ◽  
T. W. Choularton ◽  
T. Lachlan-Cope
Keyword(s):  
Heat Flux ◽  
Wind Speed ◽  
Surface Energy ◽  
Antarctic Peninsula ◽  
Energy Budget ◽  
Surface Flux ◽  
Surface Energy Budget ◽  
Ice Shelf ◽  
Aircraft Observations ◽  
The Antarctic

Abstract. Mesoscale model simulations are presented of a westerly föhn event over the Antarctic Peninsula mountain ridge and onto the Larsen C ice shelf, just south of the recently collapsed Larsen B ice shelf. Aircraft observations showed the presence of föhn jets descending near the ice shelf surface with maximum wind speeds at 250–350 m in height. Surface flux measurements suggested that melting was occurring. Simulated profiles of wind speed, temperature and wind direction were very similar to the observations. However, the good match only occurred at a model time corresponding to ~9 h before the aircraft observations were made since the model föhn jets died down after this. This was despite the fact that the model was nudged towards analysis for heights greater than ~1.15 km above the surface. Timing issues aside, the otherwise good comparison between the model and observations gave confidence that the model flow structure was similar to that in reality. Details of the model jet structure are explored and discussed and are found to have ramifications for the placement of automatic weather station (AWS) stations on the ice shelf in order to detect föhn flow. Cross sections of the flow are also examined and were found to compare well to the aircraft measurements. Gravity wave breaking above the mountain crest likely created a~situation similar to hydraulic flow and allowed föhn flow and ice shelf surface warming to occur despite strong upwind blocking, which in previous studies of this region has generally not been considered. Our results therefore suggest that reduced upwind blocking, due to wind speed increases or stability decreases, might not result in an increased likelihood of föhn events over the Antarctic Peninsula, as previously suggested. The surface energy budget of the model during the melting periods showed that the net downwelling short-wave surface flux was the largest contributor to the melting energy, indicating that the cloud clearing effect of föhn events is likely to be the most important factor for increased melting relative to non-föhn days. The results also indicate that the warmth of the föhn jets through sensible heat flux ("SH") may not be critical in causing melting beyond boundary layer stabilisation effects (which may help to prevent cloud cover and suppress loss of heat by convection) and are actually cancelled by latent heat flux ("LH") effects (snow ablation). It was found that ground heat flux ("GRD") was likely to be an important factor when considering the changing surface energy budget for the southern regions of the ice shelf as the climate warms.

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