Rapid Mass Loss in West Antarctica Revealed by Swarm Gravimetry in the Absence of GRACE

2021 ◽  
Author(s):  
Chaoyang Zhang ◽  
C. K. Shum ◽  
Aleš Bezděk ◽  
Michael Bevis ◽  
João de Teixeira da Encarnação ◽  
...  
Keyword(s):  
Mass Loss ◽  
West Antarctica ◽  
Rapid Mass

scholarly journals Glacier Surface Mass Balance in the Suntar-Khayata Mountains, Northeastern Siberia

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1949 ◽  
Author(s):  
Yong Zhang ◽  
Xin Wang ◽  
Zongli Jiang ◽  
Junfeng Wei ◽  
Hiroyuki Enomoto ◽  
...  
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Surface Mass Balance ◽  
Negative Mass ◽  
Glacier Surface ◽  
Surface Mass ◽  
Northeastern Siberia ◽  
Response To Temperature ◽  
Rapid Mass

Arctic glaciers comprise a small fraction of the world’s land ice area, but their ongoing mass loss currently represents a large cryospheric contribution to the sea level rise. In the Suntar-Khayata Mountains (SKMs) of northeastern Siberia, in situ measurements of glacier surface mass balance (SMB) are relatively sparse, limiting our understanding of the spatiotemporal patterns of regional mass loss. Here, we present SMB time series for all glaciers in the SKMs, estimated through a glacier SMB model. Our results yielded an average SMB of −0.22 m water equivalents (w.e.) year−1 for the whole region during 1951–2011. We found that 77.4% of these glaciers had a negative mass balance and detected slightly negative mass balance prior to 1991 and significantly rapid mass loss since 1991. The analysis suggests that the rapidly accelerating mass loss was dominated by increased surface melting, while the importance of refreezing in the SMB progressively decreased over time. Projections under two future climate scenarios confirmed the sustained rapid shrinkage of these glaciers. In response to temperature rise, the total present glacier area is likely to decrease by around 50% during the period 2071–2100 under representative concentration pathway 8.5 (RCP8.5).

scholarly journals Rapid mass loss and disappearance of summer-accumulation type hanging glacier

2021 ◽  
Author(s):  
X.U. Chun-hai ◽  
L.I. Zhong-qin ◽  
W.A.N.G. Fei-teng ◽  
W.A.N.G. Pu-yu ◽  
M.U. Jian-xin
Keyword(s):  
Mass Loss ◽  
Rapid Mass

scholarly journals Significant submarine ice loss from the Getz Ice Shelf, Antarctica

2018 ◽  
Author(s):  
David M. Rippin
Keyword(s):  
Mass Loss ◽  
West Antarctica ◽  
Ice Shelf ◽  
Ice Streams ◽  
Ice Shelves ◽  
Warming Climate ◽  
Circulation Patterns ◽  
Direct Measurements ◽  
Radio Echo Sounding ◽  
The Impact

Abstract. We present the first direct measurements of changes taking place at the base of the Getz Ice Shelf (GzIS) in West Antarctica. Our analysis is based on repeated airborne radio-echo sounding (RES) survey lines gathered in 2010 and 2014. We reveal that while there is significant variability in ice shelf behaviour, the vast majority of the ice shelf (where data is available) is undergoing basal thinning at a mean rate of nearly 13 m a−1, which is several times greater than recent modelling estimates. In regions of faster flowing ice close to where ice streams and outlet glaciers join the ice shelf, significantly greater rates of mass loss occurred. Since thinning is more pronounced close to faster-flowing ice, we propose that dynamic thinning processes may also contribute to mass loss here. Intricate sub-ice circulation patterns exist beneath the GzIS because of its complex sub-ice topography and the fact that it is fed by numerous ice streams and outlet glaciers. It is this complexity which we suggest is also responsible for the spatially variable patterns of ice-shelf change that we observe. The large changes observed here are also important when considering the likelihood and timing of any potential future collapse of the ice shelf, and the impact this would have on the flow rates of feeder ice streams and glaciers, that transmit ice from inland Antarctica to the coast. We propose that as the ice shelf continues to thin in response to warming ocean waters and climate, the response of the ice shelf will be spatially diverse. Given that these measurements represent changes that are significantly greater than modelling outputs, it is also clear that we still do not fully understand how ice shelves respond to warming ocean waters. As a result, ongoing direct measurements of ice shelf change are vital for understanding the future response of ice shelves under a warming climate.

scholarly journals Crossing the “Yellow Void” – Spatially Resolved Spectroscopy of the Post–Red Supergiant IRC+10420

2002 ◽  
Vol 187 ◽  
pp. 95-98
Author(s):  
Roberta M. Humphreys ◽  
Kris Davidson ◽  
Nathan Smith
Keyword(s):  
Mass Loss ◽  
Spatial Resolution ◽  
Spherically Symmetric ◽  
Bipolar Outflow ◽  
Reflection Nebula ◽  
Spatially Resolved ◽  
Spatially Resolved Spectroscopy ◽  
Rapid Mass ◽  
Hr Diagram

AbstractIRC+10420 is a post–red supergiant at the empirical luminosity boundary in the HR diagram. It has now reached a stage in its blueward evolution where increasing opacity and partial ionization destabilize its atmosphere leading to rapid mass loss. Indeed, its wind is so dense that it is opaque and hides the underlying star. We have obtained HST/STIS spectroscopy with spatial resolution good enough to separate the star from its complex ejecta with numerous arcs, knots and jet-like features. The ejecta form essentially a reflection nebula, allowing us to view the star from a range of directions. The kinematics of the ejecta cannot be reconciled with existing models with either an equatorial disk or a bipolar outflow. Therefore we propose a model with a uniform spherically symmetric outflow of gas with random, asymmetric ejections superimposed. In our model, local instabilities allow for inflowing and outflowing material to coexist.

scholarly journals High Resolution CO Observations of the Bipolar Nebula CRL2688

1987 ◽  
Vol 115 ◽  
pp. 400-402
Author(s):  
R. Kawabe ◽  
T. Kasuga ◽  
M. Ishiguro ◽  
K-I. Morita ◽  
N. Ukita ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Loss ◽  
Planetary Nebulae ◽  
Optical Emission ◽  
Central Star ◽  
Reflection Nebula ◽  
Red Giant ◽  
Molecular Envelope ◽  
Rapid Mass ◽  
Co Observations

CRL2688 is suggested to be one of the proto-planetary nebulae which are probably at a stage in which the central star is evolving from the red giant phase with rapid mass loss (Zuckerman 1978). The bipolar shape in both the optical and H2emission indicates that a dense toroid of dust and gas obscures the star and surrounds the optical emission. The toroid is probably responsible for channelling the mass loss to the polar directions (Neyet al.1975, Morris 1981, Beckwithet al.1984). We present the results of mapping observations of CO (J = 1-0) emission from the expanding molecular envelope (Zuckermanet al.1976, Loet al.1976, Knappet al.1982, Thronsonet al.1983) of the bipolar reflection nebula CRL2688 using the Nobeyama 45-m telescope with a 1.5″ resolution at a 7″.5 observing spacing.

Congregations of the leaf-shredding insect Lepidostoma togatum mediate exceptionally rapid mass loss from leaf litter in Nova Scotia rivers

Hydrobiologia ◽  
2016 ◽  
Vol 788 (1) ◽  
pp. 245-265 ◽  
Author(s):  
Irene V. Andrushchenko ◽  
Barry R. Taylor ◽  
Jantina Toxopeus ◽  
Erin Wilson
Keyword(s):  
Nova Scotia ◽  
Mass Loss ◽  
Leaf Litter ◽  
Rapid Mass

scholarly journals Retreat of Thwaites Glacier, West Antarctica, over the next 100 years using various ice flow models, ice shelf melt scenarios and basal friction laws

2018 ◽  
Author(s):  
Hongju Yu ◽  
Eric Rignot ◽  
Helene Seroussi ◽  
Mathieu Morlighem
Keyword(s):  
Mass Loss ◽  
Initial Conditions ◽  
Numerical Models ◽  
West Antarctica ◽  
Ice Shelf ◽  
Flow Models ◽  
Friction Laws ◽  
Basal Friction ◽  
Grounding Line ◽  
Western Side

Abstract. Thwaites Glacier (TG), West Antarctica, experiences rapid, potentially irreversible grounding line retreat and mass loss in response to enhanced ice shelf melting. Several numerical models of TG have been developed recently, showing a large spread in the evolution of the glacier in the coming decades to a century. It is, however, not clear how different parameterizations of basal friction and ice shelf melt or different approximations in ice stress balance affect projections.Here, we simulate the evolution of TG using different ice shelf melt, basal friction laws and ice sheet models of varying levels of complexity to quantify the effect of these model configurations on the results. We find that the grounding line retreat and its sensitivity to ocean forcing is enhanced when a full-Stokes model is used, ice shelf melt is applied on partially floating elements, and a Budd friction is used. Initial conditions also impact the model results. Yet, all simulations suggest a rapid, sustained retreat along the same preferred pathway. The highest retreat rate occurs on the eastern side of the glacier and the lowest rate on a subglacial ridge on the western side. All the simulations indicate that TG will undergo an accelerated retreat once it retreats past the western ridge. Combining the results, we find the uncertainty is small in the first 30 years, with a cumulative contribution to sea level rise of 5 mm, similar to the current rate. After 30 years, the mass loss depends on the model configurations, with a 300 % difference over the next 100 years, ranging from 14 to 42 mm.

scholarly journals Modeling the dynamic response of outlet glaciers to observed ice-shelf thinning in the Bellingshausen Sea Sector, West Antarctica

2018 ◽  
Vol 64 (244) ◽  
pp. 333-342 ◽  
Author(s):  
BRENT M. MINCHEW ◽  
G. HILMAR GUDMUNDSSON ◽  
ALEX S. GARDNER ◽  
FERNANDO S. PAOLO ◽  
HELEN A. FRICKER
Keyword(s):  
Dynamic Response ◽  
Mass Loss ◽  
Gravity Anomalies ◽  
Surface Elevation ◽  
West Antarctica ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Ice Surface ◽  
Mass Losses ◽  
Bellingshausen Sea

ABSTRACTSatellite observations of gravity anomalies, ice-surface elevation and glacier velocity show significant increases in net grounded-ice-mass loss over the past decade along the Bellingshausen Sea sector (BSS), West Antarctica, in areas where warm (>1°C) sea water floods the continental shelf. These observations provide compelling but indirect evidence that mass losses are driven primarily by reduced buttressing from the floating ice shelves caused by ocean-driven ice-shelf thinning. Here, we combine recent observations of ice velocity, thickness and thickness changes with an ice flow model to study the instantaneous dynamic response of BSS outlet glaciers to observed ice-shelf thinning, alone. Our model results show that multiple BSS outlet glaciers respond instantaneously to observed ice-shelf thinning, particularly in areas where ice shelves ground at discrete points. Increases in modeled and observed dynamic mass losses, however, account for ~5% of the mass loss rates estimated from gravity anomalies and changes in ice-surface elevation, suggesting that variations in surface mass balance may be key to understanding recent BSS mass loss. Our approach isolates the impact of ice-shelf thinning on glacier flow and shows that if ice-shelf thinning continues at or above current rates, total BSS mass loss will increase in the next decade.

scholarly journals Acceleration of Pine Island and Thwaites Glaciers, West Antarctica

2002 ◽  
Vol 34 ◽  
pp. 189-194 ◽  
Author(s):  
Eric Rignot ◽  
David G. Vaughan ◽  
Marjorie Schmeltz ◽  
Todd Dupont ◽  
Douglas Macayeal
Keyword(s):  
Mass Loss ◽  
Sea Level ◽  
Radar Interferometry ◽  
Constant Flow ◽  
West Antarctica ◽  
Ice Flow ◽  
Ice Surface ◽  
Grounding Line ◽  
Satellite Radar ◽  
Global Sea Level

AbstractRecent satellite investigations revealed that in the 1990s the grounding line of Pine Island and Thwaites Glaciers, West Antarctica, retreated several km, the ice surface on the interior of the basins lowered 10 cm a–1, and Pine Island Glacier thinned 1.6 ma–1. These observations, however, were not sufficient to determine the cause of the changes. Here, we present satellite radar interferometry data that show the thinning and retreat of Pine Island Glacier are caused by an acceleration of ice flow of about 18 ± 2% in 8 years. Thwaites Glacier maintained a nearly constant flow regime at its center, but widened along the sides, and increased its 30 ± 15% mass deficit by another 4% in 4 years. The combined mass loss from both glaciers, if correct, contributes an estimated 0.08 ± 0.03 mma–1 global sea-level rise in 2000.

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