Assessing Present-Day Atmospheric Control Over the Surface Mass Balance of Patagonian Icefields Through Modeling

Abstract We present continuous estimates of snow and firn density, layer depth and accumulation from a multi-channel, multi-offset, ground-penetrating radar traverse. Our method uses the electromagnetic velocity, estimated from waveform travel-times measured at common-midpoints between sources and receivers. Previously, common-midpoint radar experiments on ice sheets have been limited to point observations. We completed radar velocity analysis in the upper ~2 m to estimate the surface and average snow density of the Greenland Ice Sheet. We parameterized the Herron and Langway (1980) firn density and age model using the radar-derived snow density, radar-derived surface mass balance (2015–2017) and reanalysis-derived temperature data. We applied structure-oriented filtering to the radar image along constant age horizons and increased the depth at which horizons could be reliably interpreted. We reconstructed the historical instantaneous surface mass balance, which we averaged into annual and multidecadal products along a 78 km traverse for the period 1984–2017. We found good agreement between our physically constrained parameterization and a firn core collected from the dry snow accumulation zone, and gained insights into the spatial correlation of surface snow density.

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

Water ◽

10.3390/w11091949 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1949 ◽

Cited By ~ 1

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).

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Long-range terrestrial laser scanning measurements of annual and intra-annual mass balances for Urumqi Glacier No. 1, eastern Tien Shan, China

The Cryosphere ◽

10.5194/tc-13-2361-2019 ◽

2019 ◽

Vol 13 (9) ◽

pp. 2361-2383 ◽

Cited By ~ 8

Author(s):

Chunhai Xu ◽

Zhongqin Li ◽

Huilin Li ◽

Feiteng Wang ◽

Ping Zhou

Keyword(s):

Mass Balance ◽

Long Range ◽

Tien Shan ◽

Glacier Mass Balance ◽

Surface Mass Balance ◽

Mass Balances ◽

Surface Mass ◽

Mass Conversion ◽

Geodetic Mass Balance

Abstract. The direct glaciological method provides in situ observations of annual or seasonal surface mass balance, but can only be implemented through a succession of intensive in situ measurements of field networks of stakes and snow pits. This has contributed to glacier surface mass-balance measurements being sparse and often discontinuous in the Tien Shan. Nevertheless, long-term glacier mass-balance measurements are the basis for understanding climate–glacier interactions and projecting future water availability for glacierized catchments in the Tien Shan. Riegl VZ®-6000 long-range terrestrial laser scanner (TLS), typically using class 3B laser beams, is exceptionally well suited for repeated glacier mapping, and thus determination of annual and seasonal geodetic mass balance. This paper introduces the applied TLS for monitoring summer and annual surface elevation and geodetic mass changes of Urumqi Glacier No. 1 as well as delineating accurate glacier boundaries for 2 consecutive mass-balance years (2015–2017), and discusses the potential of such technology in glaciological applications. Three-dimensional changes of ice and firn–snow bodies and the corresponding densities were considered for the volume-to-mass conversion. The glacier showed pronounced thinning and mass loss for the four investigated periods; glacier-wide geodetic mass balance in the mass-balance year 2015–2016 was slightly more negative than in 2016–2017. Statistical comparison shows that agreement between the glaciological and geodetic mass balances can be considered satisfactory, indicating that the TLS system yields accurate results and has the potential to monitor remote and inaccessible glacier areas where no glaciological measurements are available as the vertical velocity component of the glacier is negligible. For wide applications of the TLS in glaciology, we should use stable scan positions and in-situ-measured densities of snow–firn to establish volume-to-mass conversion.

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Contemporary (1960–2012) Evolution of the Climate and Surface Mass Balance of the Greenland Ice Sheet

Surveys in Geophysics ◽

10.1007/s10712-013-9261-z ◽

2013 ◽

Vol 35 (5) ◽

pp. 1155-1174 ◽

Cited By ~ 73

Author(s):

J. H. van Angelen ◽

M. R. van den Broeke ◽

B. Wouters ◽

J. T. M. Lenaerts

Keyword(s):

Mass Balance ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Surface Mass Balance ◽

Surface Mass

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Meteorological conditions over Antarctic blue-ice areas and their influence on the local surface mass balance

Journal of Glaciology ◽

10.3189/172756501781832557 ◽

2001 ◽

Vol 47 (156) ◽

pp. 37-50 ◽

Cited By ~ 36

Author(s):

Richard Bintanja ◽

Carleen H. Reijmer

Keyword(s):

Mass Balance ◽

Low Frequency ◽

Meteorological Conditions ◽

Surface Mass Balance ◽

Surface Mass ◽

Wind Speeds ◽

Dry Conditions ◽

The Difference ◽

Sublimation Rates ◽

Different Characteristics

AbstractThis paper addresses the causes of the prevailing meteorological conditions observed over an Antarctic blue-ice area and their effect on the surface mass balance. Over blue-ice areas, net accumulation is zero and ablation occurs mainly through sublimation. Sublimation rates are much higher than over adjacent snowfields. The meteorological conditions favourable for high sublimation rates (warm, dry and gusty) are due to the specific orographic setting of this blue-ice area, with usually a steep upwind mountainous slope causing strong adiabatic heating. Diabatic warming due to radiation, and entrainment of warm air from aloft into the boundary layer augment the warming. The prevailing warm, dry conditions explain roughly 50% of the difference in sublimation, and the different characteristics of blue ice (mainly its lower albedo) the other 50%. Most of the annual sublimation (∼70%) takes place during the short summer (mainly in daytime), with winter ablation being restricted to occasional warm, dry föhn-like events. The additional moisture is effectively removed by entrainment and horizontal advection, which are maximum over the blue-ice area. Low-frequency turbulent motions induced by the upwind mountains enhance the vertical turbulent transports. Strong gusts and high peak wind speeds over blue-ice areas cause high potential snowdrift transports, which can easily remove the total precipitation, thereby maintaining zero accumulation.

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Surface elevation changes during 2007–13 on Bowdoin and Tugto Glaciers, northwestern Greenland

Journal of Glaciology ◽

10.1017/jog.2016.106 ◽

2016 ◽

Vol 62 (236) ◽

pp. 1083-1092 ◽

Cited By ~ 14

Author(s):

SHUN TSUTAKI ◽

SHIN SUGIYAMA ◽

DAIKI SAKAKIBARA ◽

TAKANOBU SAWAGAKI

Keyword(s):

Mass Balance ◽

Satellite Observations ◽

Surface Elevation ◽

Surface Mass Balance ◽

Elevation Change ◽

Predominant Role ◽

Ice Dynamics ◽

Surface Mass ◽

Elevation Changes ◽

Negative Surface

ABSTRACTTo quantify recent thinning of marine-terminating outlet glaciers in northwestern Greenland, we carried out field and satellite observations near the terminus of Bowdoin Glacier. These data were used to compute the change in surface elevation from 2007 to 2013 and this rate of thinning was then compared with that of the adjacent land-terminating Tugto Glacier. Comparing DEMs of 2007 and 2010 shows that Bowdoin Glacier is thinning more rapidly (4.1 ± 0.3 m a−1) than Tugto Glacier (2.8 ± 0.3 m a−1). The observed negative surface mass-balance accounts for <40% of the elevation change of Bowdoin Glacier, meaning that the thinning of Bowdoin Glacier cannot be attributable to surface melting alone. The ice speed of Bowdoin Glacier increases down-glacier, reaching 457 m a−1 near the calving front. This flow regime causes longitudinal stretching and vertical compression at a rate of −0.04 a−1. It is likely that this dynamically-controlled thinning has been enhanced by the acceleration of the glacier since 2000. Our measurements indicate that ice dynamics indeed play a predominant role in the rapid thinning of Bowdoin Glacier.

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Simulation of the future sea level contribution of Greenland with a new glacial system model

The Cryosphere ◽

10.5194/tc-12-3097-2018 ◽

2018 ◽

Vol 12 (10) ◽

pp. 3097-3121 ◽

Cited By ~ 17

Author(s):

Reinhard Calov ◽

Sebastian Beyer ◽

Ralf Greve ◽

Johanna Beckmann ◽

Matteo Willeit ◽

...

Keyword(s):

Boundary Conditions ◽

Surface Temperature ◽

Mass Balance ◽

Sea Level Rise ◽

Sea Level ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

System Model ◽

Surface Mass Balance ◽

Surface Mass

Abstract. We introduce the coupled model of the Greenland glacial system IGLOO 1.0, including the polythermal ice sheet model SICOPOLIS (version 3.3) with hybrid dynamics, the model of basal hydrology HYDRO and a parameterization of submarine melt for marine-terminated outlet glaciers. The aim of this glacial system model is to gain a better understanding of the processes important for the future contribution of the Greenland ice sheet to sea level rise under future climate change scenarios. The ice sheet is initialized via a relaxation towards observed surface elevation, imposing the palaeo-surface temperature over the last glacial cycle. As a present-day reference, we use the 1961–1990 standard climatology derived from simulations of the regional atmosphere model MAR with ERA reanalysis boundary conditions. For the palaeo-part of the spin-up, we add the temperature anomaly derived from the GRIP ice core to the years 1961–1990 average surface temperature field. For our projections, we apply surface temperature and surface mass balance anomalies derived from RCP 4.5 and RCP 8.5 scenarios created by MAR with boundary conditions from simulations with three CMIP5 models. The hybrid ice sheet model is fully coupled with the model of basal hydrology. With this model and the MAR scenarios, we perform simulations to estimate the contribution of the Greenland ice sheet to future sea level rise until the end of the 21st and 23rd centuries. Further on, the impact of elevation–surface mass balance feedback, introduced via the MAR data, on future sea level rise is inspected. In our projections, we found the Greenland ice sheet to contribute between 1.9 and 13.0 cm to global sea level rise until the year 2100 and between 3.5 and 76.4 cm until the year 2300, including our simulated additional sea level rise due to elevation–surface mass balance feedback. Translated into additional sea level rise, the strength of this feedback in the year 2100 varies from 0.4 to 1.7 cm, and in the year 2300 it ranges from 1.7 to 21.8 cm. Additionally, taking the Helheim and Store glaciers as examples, we investigate the role of ocean warming and surface runoff change for the melting of outlet glaciers. It shows that ocean temperature and subglacial discharge are about equally important for the melting of the examined outlet glaciers.

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Estimation of the Sea Level Rise by 2100 Resulting from Changes in the Surface Mass Balance of the Greenland Ice Sheet

Climate Change - Geophysical Foundations and Ecological Effects ◽

10.5772/23913 ◽

2011 ◽

Cited By ~ 10

Author(s):

Xavier Fettweis ◽

Alexandre Belleflamme ◽

Michel Erpicum ◽

Bruno Franco ◽

Samuel Nicolay

Keyword(s):

Mass Balance ◽

Sea Level Rise ◽

Sea Level ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Surface Mass Balance ◽

Surface Mass

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Observationally constrained surface mass balance of Larsen C ice shelf, Antarctica

The Cryosphere ◽

10.5194/tc-11-2411-2017 ◽

2017 ◽

Vol 11 (6) ◽

pp. 2411-2426 ◽

Cited By ~ 7

Author(s):

Peter Kuipers Munneke ◽

Daniel McGrath ◽

Brooke Medley ◽

Adrian Luckman ◽

Suzanne Bevan ◽

...

Keyword(s):

Mass Balance ◽

Climate Model ◽

Regional Climate ◽

Snow Accumulation ◽

Airborne Radar ◽

Surface Mass Balance ◽

Spatial And Temporal Patterns ◽

Ice Shelf ◽

The West ◽

Surface Mass

Abstract. The surface mass balance (SMB) of the Larsen C ice shelf (LCIS), Antarctica, is poorly constrained due to a dearth of in situ observations. Combining several geophysical techniques, we reconstruct spatial and temporal patterns of SMB over the LCIS. Continuous time series of snow height (2.5–6 years) at five locations allow for multi-year estimates of seasonal and annual SMB over the LCIS. There is high interannual variability in SMB as well as spatial variability: in the north, SMB is 0.40 ± 0.06 to 0.41 ± 0.04 m w.e. year−1, while farther south, SMB is up to 0.50 ± 0.05 m w.e. year−1. This difference between north and south is corroborated by winter snow accumulation derived from an airborne radar survey from 2009, which showed an average snow thickness of 0.34 m w.e. north of 66° S, and 0.40 m w.e. south of 68° S. Analysis of ground-penetrating radar from several field campaigns allows for a longer-term perspective of spatial variations in SMB: a particularly strong and coherent reflection horizon below 25–44 m of water-equivalent ice and firn is observed in radargrams collected across the shelf. We propose that this horizon was formed synchronously across the ice shelf. Combining snow height observations, ground and airborne radar, and SMB output from a regional climate model yields a gridded estimate of SMB over the LCIS. It confirms that SMB increases from north to south, overprinted by a gradient of increasing SMB to the west, modulated in the west by föhn-induced sublimation. Previous observations show a strong decrease in firn air content toward the west, which we attribute to spatial patterns of melt, refreezing, and densification rather than SMB.

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