scholarly journals Geothermal heat flux in the Amundsen Sea sector of West Antarctica: New insights from temperature measurements, depth to the bottom of the magnetic source estimation, and thermal modeling

2017 ◽  
Vol 18 (7) ◽  
pp. 2657-2672 ◽  
Author(s):  
R. Dziadek ◽  
K. Gohl ◽  
A. Diehl ◽  
N. Kaul
Keyword(s):  
Heat Flux ◽  
Thermal Modeling ◽  
Temperature Measurements ◽  
West Antarctica ◽  
Geothermal Heat ◽  
Amundsen Sea ◽  
Source Estimation ◽  
Magnetic Source

scholarly journals High geothermal heat flow beneath Thwaites Glacier in West Antarctica inferred from aeromagnetic data

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Ricarda Dziadek ◽  
Fausto Ferraccioli ◽  
Karsten Gohl
Keyword(s):  
Heat Flow ◽  
Ice Sheet ◽  
West Antarctica ◽  
The West ◽  
Geothermal Heat ◽  
Amundsen Sea ◽  
Continental Scale ◽  
West Antarctic ◽  
Curie Depth ◽  
Depth Analysis

AbstractGeothermal heat flow in the polar regions plays a crucial role in understanding ice-sheet dynamics and predictions of sea level rise. Continental-scale indirect estimates often have a low spatial resolution and yield largest discrepancies in West Antarctica. Here we analyse geophysical data to estimate geothermal heat flow in the Amundsen Sea Sector of West Antarctica. With Curie depth analysis based on a new magnetic anomaly grid compilation, we reveal variations in lithospheric thermal gradients. We show that the rapidly retreating Thwaites and Pope glaciers in particular are underlain by areas of largely elevated geothermal heat flow, which relates to the tectonic and magmatic history of the West Antarctic Rift System in this region. Our results imply that the behavior of this vulnerable sector of the West Antarctic Ice Sheet is strongly coupled to the dynamics of the underlying lithosphere.

Variable crustal thickness beneath Thwaites Glacier revealed from airborne gravimetry, possible implications for geothermal heat flux in West Antarctica

2014 ◽  
Vol 407 ◽  
pp. 109-122 ◽  
Author(s):  
Theresa M. Damiani ◽  
Tom A. Jordan ◽  
Fausto Ferraccioli ◽  
Duncan A. Young ◽  
Donald D. Blankenship
Keyword(s):  
Heat Flux ◽  
Crustal Thickness ◽  
Airborne Gravimetry ◽  
West Antarctica ◽  
Geothermal Heat

scholarly journals Spatially Variable Geothermal Heat Flux in West Antarctica: Evidence and Implications

2017 ◽  
Vol 44 (19) ◽  
pp. 9823-9832 ◽  
Author(s):  
Carolyn Branecky Begeman ◽  
Slawek M. Tulaczyk ◽  
Andrew T. Fisher
Keyword(s):  
Heat Flux ◽  
West Antarctica ◽  
Geothermal Heat

scholarly journals A Joint Inversion Estimate of Antarctic Ice Sheet Mass Balance Using Multi-Geodetic Data Sets

2019 ◽  
Vol 11 (6) ◽  
pp. 653 ◽  
Author(s):  
Chunchun Gao ◽  
Yang Lu ◽  
Zizhan Zhang ◽  
Hongling Shi
Keyword(s):  
Mass Balance ◽  
Joint Inversion ◽  
Ice Sheet ◽  
Mass Change ◽  
West Antarctica ◽  
Amundsen Sea ◽  
Antarctic Ice Sheet ◽  
Forward Models ◽  
Uplift Rates ◽  
The Antarctic

Many recent mass balance estimates using the Gravity Recovery and Climate Experiment (GRACE) and satellite altimetry (including two kinds of sensors of radar and laser) show that the ice mass of the Antarctic ice sheet (AIS) is in overall decline. However, there are still large differences among previously published estimates of the total mass change, even in the same observed periods. The considerable error sources mainly arise from the forward models (e.g., glacial isostatic adjustment [GIA] and firn compaction) that may be uncertain but indispensable to simulate some processes not directly measured or obtained by these observations. To minimize the use of these forward models, we estimate the mass change of ice sheet and present-day GIA using multi-geodetic observations, including GRACE and Ice, Cloud and land Elevation Satellite (ICESat), as well as Global Positioning System (GPS), by an improved method of joint inversion estimate (JIE), which enables us to solve simultaneously for the Antarctic GIA and ice mass trends. The GIA uplift rates generated from our JIE method show a good agreement with the elastic-corrected GPS uplift rates, and the total GIA-induced mass change estimate for the AIS is 54 ± 27 Gt/yr, which is in line with many recent GPS calibrated GIA estimates. Our GIA result displays the presence of significant uplift rates in the Amundsen Sea Embayment of West Antarctica, where strong uplift has been observed by GPS. Over the period February 2003 to October 2009, the entire AIS changed in mass by −84 ± 31 Gt/yr (West Antarctica: −69 ± 24, East Antarctica: 12 ± 16 and the Antarctic Peninsula: −27 ± 8), greater than the GRACE-only estimates obtained from three Mascon solutions (CSR: −50 ± 30, JPL: −71 ± 30, and GSFC: −51 ± 33 Gt/yr) for the same period. This may imply that single GRACE data tend to underestimate ice mass loss due to the signal leakage and attenuation errors of ice discharge are often worse than that of surface mass balance over the AIS.

scholarly journals The Amundsen Sea Low: Variability, Change, and Impact on Antarctic Climate

2016 ◽  
Vol 97 (1) ◽  
pp. 111-121 ◽  
Author(s):  
M. N. Raphael ◽  
G. J. Marshall ◽  
J. Turner ◽  
R. L. Fogt ◽  
D. Schneider ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Model ◽  
Ross Sea ◽  
Ice Core ◽  
Meridional Wind ◽  
West Antarctica ◽  
Sea Ice Extent ◽  
Amundsen Sea ◽  
West Antarctic ◽  
Climate Model Simulations

Abstract The Amundsen Sea low (ASL) is a climatological low pressure center that exerts considerable influence on the climate of West Antarctica. Its potential to explain important recent changes in Antarctic climate, for example, in temperature and sea ice extent, means that it has become the focus of an increasing number of studies. Here, the authors summarize the current understanding of the ASL, using reanalysis datasets to analyze recent variability and trends, as well as ice-core chemistry and climate model projections, to examine past and future changes in the ASL, respectively. The ASL has deepened in recent decades, affecting the climate through its influence on the regional meridional wind field, which controls the advection of moisture and heat into the continent. Deepening of the ASL in spring is consistent with observed West Antarctic warming and greater sea ice extent in the Ross Sea. Climate model simulations for recent decades indicate that this deepening is mediated by tropical variability while climate model projections through the twenty-first century suggest that the ASL will deepen in some seasons in response to greenhouse gas concentration increases.

The effect of geothermal heat flux on the deglacial evolution of the Greenland ice sheet

2021 ◽  
Author(s):  
Parviz Ajourlou ◽  
François PH Lapointe ◽  
Glenn A Milne ◽  
Yasmina Martos
Keyword(s):  
Boundary Condition ◽  
Heat Flux ◽  
Thermal State ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Sampling Procedure ◽  
Geophysical Research ◽  
Geothermal Heat ◽  
Input Field ◽  
Uncertainty Estimates

<p>Geothermal heat flux (GHF) is known to be an important control on the basal thermal state of an ice sheet which, in turn, is a key factor in governing how the ice sheet will evolve in response to a given climate forcing. In recent years, several studies have estimated GHF beneath the Greenland ice sheet using different approaches (e.g. Rezvanbehbahani et al., Geophysical Research Letters, 2017; Martos et al., Geophysical Research Letters, 2018; Greve, Polar Data Journal, 2019). Comparing these different estimates indicates poor agreement and thus large uncertainty in our knowledge of this important boundary condition for modelling the ice sheet. The primary aim of this study is to quantify the influence of this uncertainty on modelling the past evolution of the ice sheet with a focus on the most recent deglaciation. We build on past work that considered three GHF models (Rogozhina et al., 2011) by considering over 100 different realizations of this input field. We use the uncertainty estimates from Martos et al. (Geophysical Research Letters, 2018) to generate GHF realisations via a statistical sampling procedure. A sensitivity analysis using these realisations and the Parallel Ice Sheet Model (PISM, Bueler and Brown, Journal of Geophysical Research, 2009) indicates that uncertainty in GHF has a dramatic impact on both the volume and spatial distribution of ice since the last glacial maximum, indicating that more precise constraints on this boundary condition are required to improve our understanding of past ice sheet evolution and, consequently, reduce uncertainty in future projections.</p>

scholarly journals Meteorological Drivers and Large-Scale Climate Forcing of West Antarctic Surface Melt

2019 ◽  
Vol 32 (3) ◽  
pp. 665-684 ◽  
Author(s):  
Ryan C. Scott ◽  
Julien P. Nicolas ◽  
David H. Bromwich ◽  
Joel R. Norris ◽  
Dan Lubin
Keyword(s):  
Sea Ice ◽  
Ice Sheet ◽  
Climate Forcing ◽  
West Antarctica ◽  
Sea Ice Concentration ◽  
Amundsen Sea ◽  
West Antarctic ◽  
Ice Concentration ◽  
Surface Melt ◽  
Marine Air

Understanding the drivers of surface melting in West Antarctica is crucial for understanding future ice loss and global sea level rise. This study identifies atmospheric drivers of surface melt on West Antarctic ice shelves and ice sheet margins and relationships with tropical Pacific and high-latitude climate forcing using multidecadal reanalysis and satellite datasets. Physical drivers of ice melt are diagnosed by comparing satellite-observed melt patterns to anomalies of reanalysis near-surface air temperature, winds, and satellite-derived cloud cover, radiative fluxes, and sea ice concentration based on an Antarctic summer synoptic climatology spanning 1979–2017. Summer warming in West Antarctica is favored by Amundsen Sea (AS) blocking activity and a negative phase of the southern annular mode (SAM), which both correlate with El Niño conditions in the tropical Pacific Ocean. Extensive melt events on the Ross–Amundsen sector of the West Antarctic Ice Sheet (WAIS) are linked to persistent, intense AS blocking anticyclones, which force intrusions of marine air over the ice sheet. Surface melting is primarily driven by enhanced downwelling longwave radiation from clouds and a warm, moist atmosphere and by turbulent mixing of sensible heat to the surface by föhn winds. Since the late 1990s, concurrent with ocean-driven WAIS mass loss, summer surface melt occurrence has increased from the Amundsen Sea Embayment to the eastern Ross Ice Shelf. We link this change to increasing anticyclonic advection of marine air into West Antarctica, amplified by increasing air–sea fluxes associated with declining sea ice concentration in the coastal Ross–Amundsen Seas.

Flow, thermal structure, and subglacial conditions of a surge-type glacier

1984 ◽  
Vol 21 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Garry K. C. Clarke ◽  
Sam G. Collins ◽  
David E. Thompson
Keyword(s):  
Energy Source ◽  
Heat Flux ◽  
Thermal Structure ◽  
Drainage System ◽  
Temperature Measurements ◽  
Bottom Temperature ◽  
Water Percolation ◽  
Geothermal Flux

Temperature measurements in a subpolar surge-type glacier reveal a distinctive thermal structure associated with the boundary between the ice reservoir and receiving areas. In the receiving area the glacier is cold based, but bottom temperature has increased as much as 0.5 °C between 1981 and 1982, and the basal heat flux is roughly 10 times the expected geothermal flux. Water percolation through permeable subglacial material is the probable energy source. Deformation of the substrate could destroy this drainage system and trigger a surge.

scholarly journals Glacial retreat in the Amundsen Sea sector, West Antarctica – first cosmogenic evidence from central Pine Island Bay and the Kohler Range

2014 ◽  
Vol 98 ◽  
pp. 166-173 ◽  
Author(s):  
Julia Lindow ◽  
Marion Castex ◽  
Hella Wittmann ◽  
Joanne S. Johnson ◽  
Frank Lisker ◽  
...  
Keyword(s):  
West Antarctica ◽  
Amundsen Sea ◽  
Glacial Retreat
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