scholarly journals Snow Accumulation in North Greenland

1958 ◽  
Vol 3 (24) ◽  
pp. 237-248 ◽  
Author(s):  
C. Bull
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
The Mean ◽  
Precipitation Records ◽  
Available Information ◽  
North Greenland

AbstractMeasurements of the annual snow accumulation have been made at many points on a traverse of north Greenland. In lat. 77–78° N. the annual accumulation above 1800 m. was about 13 gm. cm.−2in the years 1948–53 and, in contrast to results which have been obtained further south, did not vary with longitude. In 1953–54 the accumulation was greater. The annual accumulation in north and central Greenland has varied significantly over the last 50 years, but similar variations are not shown in the precipitation records at coastal stations. Using all the available information, the mean annual accumulation on the Greenland Ice Sheet has been calculated as 29±3 gm. cm.−2.

scholarly journals Snow Accumulation in North Greenland

1958 ◽  
Vol 3 (24) ◽  
pp. 237-248 ◽  
Author(s):  
C. Bull
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
The Mean ◽  
Precipitation Records ◽  
Available Information ◽  
North Greenland

AbstractMeasurements of the annual snow accumulation have been made at many points on a traverse of north Greenland. In lat. 77–78° N. the annual accumulation above 1800 m. was about 13 gm. cm.−2 in the years 1948–53 and, in contrast to results which have been obtained further south, did not vary with longitude. In 1953–54 the accumulation was greater. The annual accumulation in north and central Greenland has varied significantly over the last 50 years, but similar variations are not shown in the precipitation records at coastal stations. Using all the available information, the mean annual accumulation on the Greenland Ice Sheet has been calculated as 29±3 gm. cm.−2.

scholarly journals Recent North Greenland temperature warming and accumulation

2021 ◽  
Author(s):  
Helle Astrid Kjær ◽  
Patrick Zens ◽  
Ross Edwards ◽  
Martin Olesen ◽  
Ruth Mottram ◽  
...  
Keyword(s):  
Mass Balance ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Topographic Effects ◽  
North East ◽  
The North ◽  
North Greenland

Abstract. In a warming climate concise knowledge of the mass balance of the Greenland ice sheet is of utter importance. Speculations that current warming will increase the snow accumulation and mitigate mass balance losses are unconstrained as accumulation data across large regions of the northern ice sheet are scarce. We reconstructed the accumulation from six north Greenland shallow firn cores (~10 m) and eight snow cores (~2 m) to constrain recent accumulation patterns in northern Greenland and calculated recent warming in the same area using borehole temperature measurements. We find an increase in temperatures in the north Greenland interior of 0.9 to 2.5 °C (method and site dependent) per decade over the past two decades in line with an Arctic amplified anthropogenic warming. We compare annual reconstructed accumulation from the firn cores (1966–2015) to radar estimates and to annual re-analysis data (1980–2016) of precipitation subtracted evaporation from the regional climate model HIRHAM5, operated by the Danish Meteorological Institute. The spatial variability resembles that observed in earlier estimates with a clear increase west of the topographic divide and a low accumulation area across the north-eastern ice sheet. Our accumulation results are comparable to earlier firn core estimates, despite being larger in the east. We only find a positive significant trend in the accumulation for the period 2000–2010 to the northwest. In the vicinity of the EGRIP deep ice core drilling site, we find variable accumulation patterns for two 15 km apart firn cores likely owing to local topographic effects as a result of the North East Greenland Ice Stream dynamics.

Changes in Greenland ice sheet elevation attributed primarily to snow accumulation variability

Nature ◽  
2000 ◽  
Vol 406 (6798) ◽  
pp. 877-879 ◽  
Author(s):  
J. R. McConnell ◽  
R. J. Arthern ◽  
E. Mosley-Thompson ◽  
C. H. Davis ◽  
R. C. Bales ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation

scholarly journals How warm was Greenland during the last interglacial period?

2016 ◽  
Vol 12 (9) ◽  
pp. 1933-1948 ◽  
Author(s):  
Amaelle Landais ◽  
Valérie Masson-Delmotte ◽  
Emilie Capron ◽  
Petra M. Langebroek ◽  
Pepijn Bakker ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Water Isotopes ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Last Interglacial Period ◽  
Ice Sheet Topography ◽  
North Greenland

Abstract. The last interglacial period (LIG, ∼ 129–116 thousand years ago) provides the most recent case study of multimillennial polar warming above the preindustrial level and a response of the Greenland and Antarctic ice sheets to this warming, as well as a test bed for climate and ice sheet models. Past changes in Greenland ice sheet thickness and surface temperature during this period were recently derived from the North Greenland Eemian Ice Drilling (NEEM) ice core records, northwest Greenland. The NEEM paradox has emerged from an estimated large local warming above the preindustrial level (7.5 ± 1.8 °C at the deposition site 126 kyr ago without correction for any overall ice sheet altitude changes between the LIG and the preindustrial period) based on water isotopes, together with limited local ice thinning, suggesting more resilience of the real Greenland ice sheet than shown in some ice sheet models. Here, we provide an independent assessment of the average LIG Greenland surface warming using ice core air isotopic composition (δ15N) and relationships between accumulation rate and temperature. The LIG surface temperature at the upstream NEEM deposition site without ice sheet altitude correction is estimated to be warmer by +8.5 ± 2.5 °C compared to the preindustrial period. This temperature estimate is consistent with the 7.5 ± 1.8 °C warming initially determined from NEEM water isotopes but at the upper end of the preindustrial period to LIG temperature difference of +5.2 ± 2.3 °C obtained at the NGRIP (North Greenland Ice Core Project) site by the same method. Climate simulations performed with present-day ice sheet topography lead in general to a warming smaller than reconstructed, but sensitivity tests show that larger amplitudes (up to 5 °C) are produced in response to prescribed changes in sea ice extent and ice sheet topography.

scholarly journals Snow Accumulation Studies on the Thule Peninsula, Greenland

1968 ◽  
Vol 7 (49) ◽  
pp. 59-76 ◽  
Author(s):  
Steven J. Mock
Keyword(s):  
Regional Scale ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Accumulation Rates ◽  
Surface Slope ◽  
Ice Flow ◽  
Accumulation Pattern ◽  
Flow Phenomena ◽  
Independent Parameters

AbstractData from stake measurements, marker boards and pits along a 136 km trail crossing the Thule peninsula sector of the Greenland ice sheet have been used to determine both the regional and local distribution of snow accumulation, On a regional scale trend surfaces of mean annual accumulation can be adequately predicted from a model using distance from moisture source and elevation as independent parameters. A series of step- or wave-like features break the smooth profile of the ice. sheet and cause profound changes in accumulation rates on a local scale. The accumulation pattern over these features can be predicted from surface slope and departure from regional elevation. Profiles of’ surface and subsurface topography indicate a direct relationship between subsurface hills and step-like features, but cannot be quantitatively accounted for by existing ice-flow theory. Detailed accumulation studies in conjunction with a program of spirit leveling in the vicinity of Camp Century has revealed the development a shallow valley-like feature. Within this feature accumulation rates have increased indicating that it is the result of flow phenomena.

scholarly journals Accumulation and Temperature on The Inland Ice of North Greenland, 1959

1961 ◽  
Vol 3 (30) ◽  
pp. 1017-1044 ◽  
Author(s):  
Chester C. Langway
Keyword(s):  
Snow Accumulation ◽  
Surface Slope ◽  
Empirical Correlations ◽  
Altitude Gradient ◽  
Local Climate ◽  
The Mean ◽  
Inland Ice ◽  
Deep Pits ◽  
North Greenland ◽  
Linear Trends

AbstractTwelve deep pits (5 to 5.5 m.) revealed between 6 and 13 years of snow accumulation. The results show an average net accumulation of 18.5 g./cm.2per year. Accumulation decreases inland at a mean rate of 1.5 g./cm.2per 100 m. rise in elevation. Temperature measurements at 100 m. in all pits give a mean temperature-altitude gradient of 0.77° C. per 100 m. Evidence of melt was observed in all pits, the most pronounced melt occurring in 1954. The mean density reflects the local climate. Other empirical correlations of these data show linear trends that vary systematically with surface slope and local climate.

scholarly journals Mass balance of the northeast sector of the Greenland ice sheet: a remote-sensing perspective

2000 ◽  
Vol 46 (153) ◽  
pp. 265-273 ◽  
Author(s):  
Eric Rignot ◽  
Guillaume Buscarlet ◽  
Beáta Csathó ◽  
Sivaprasad Gogineni ◽  
William Krabill ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Ice Shelf ◽  
Synthetic Aperture Radar Interferometry ◽  
Model Predictions ◽  
Grounding Line ◽  
Ice Production ◽  
Inland Ice

AbstractSynthetic-aperture radar interferometry data and airborne ice-sounding radar (ISR) data are employed to obtain modern estimates of the inland ice production from Nioghalvfjerdsbræ (NB) and Zachariae Isstrøm (ZI), the two largest glaciers draining the northeast sector of the Greenland ice sheet. Ice fluxes are measured at the grounding line (14.2 ±1 km3 ice a−1 for NB and 10.8 ±1 km3 ice a−1 for ZI) with an ice thickness deduced from ice-shelf hydrostatic equilibrium, and along an ISR profile collected upstream of the grounding line (14.3 ± 0.7 km3 ice a−1 for NB and 11.6 ± 0.6 km3 ice a−1 for ZI). Balance fluxes calculated from a map of snow accumulation and model predictions of surface melt are 11.9 ± 2 km3 ice a−1 for NB and 10.0 ± 2 km3 ice a−1 for ZI at the grounding line, and 12.2 and 10.3 km3 ice a−1, respectively, at the ISR line. The two glaciers therefore exhibit a negative mass balance equivalent to 14% of their balance flux, with a ±12% uncertainty. Independently, we detect a retreat of the grounding line of NB between 1992 and 1996 which is larger at the glacier center (920 ± 250 m) than on the sides (240 ± 50 m). The corresponding ice-thinning rates (2 ± 1 m a−1 at the glacier center and 0.6 ± 0.3 m a−1 on the sides) are too large to be accommodated by temporal changes in ablation or accumulation, and must be due to dynamic thinning.

scholarly journals Snow Accumulation Studies on the Thule Peninsula, Greenland

1968 ◽  
Vol 7 (49) ◽  
pp. 59-76 ◽  
Author(s):  
Steven J. Mock
Keyword(s):  
Regional Scale ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Accumulation Rates ◽  
Surface Slope ◽  
Ice Flow ◽  
Accumulation Pattern ◽  
Flow Phenomena ◽  
Independent Parameters

Abstract Data from stake measurements, marker boards and pits along a 136 km trail crossing the Thule peninsula sector of the Greenland ice sheet have been used to determine both the regional and local distribution of snow accumulation, On a regional scale trend surfaces of mean annual accumulation can be adequately predicted from a model using distance from moisture source and elevation as independent parameters. A series of step- or wave-like features break the smooth profile of the ice. sheet and cause profound changes in accumulation rates on a local scale. The accumulation pattern over these features can be predicted from surface slope and departure from regional elevation. Profiles of’ surface and subsurface topography indicate a direct relationship between subsurface hills and step-like features, but cannot be quantitatively accounted for by existing ice-flow theory. Detailed accumulation studies in conjunction with a program of spirit leveling in the vicinity of Camp Century has revealed the development a shallow valley-like feature. Within this feature accumulation rates have increased indicating that it is the result of flow phenomena.

scholarly journals Recent changes on Greenland outlet glaciers

2009 ◽  
Vol 55 (189) ◽  
pp. 147-162 ◽  
Author(s):  
R. Thomas ◽  
E. Frederick ◽  
W. Krabill ◽  
S. Manizade ◽  
C. Martin
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Dynamic Changes ◽  
Laser Altimeter ◽  
Outlet Glacier ◽  
Thickness Change ◽  
Grounding Line ◽  
Break Up ◽  
Glacier Velocity

AbstractAircraft laser-altimeter surveys during the 1990s showed near-coastal parts of the Greenland ice sheet to be thinning; despite slow thickening at higher elevations, the ice sheet lost mass to the ocean. Many outlet glaciers thinned more rapidly than could be explained by increased melting during the recent warmer summers, indicating dynamic imbalance between glacier velocity and upstream snow accumulation. Results from more recent surveys, presented here, show that thinning rates have increased in most coastal regions. For almost half of the surveys, these increases might have resulted from increases in summer melting, but rapid thinning on others is indicative of dynamic changes that increased with time. In particular, thinning rates on the three fastest glaciers increased to tens of m a−1 after 2000, and other observations show an approximate doubling in their velocities. The deep beds of these glaciers appear to have a strong influence on rates of grounding-line retreat and thickness change, with periods of glacier acceleration and rapid thinning initiated by flotation and break-up of lightly grounded glacier snouts or break-up of floating ice tongues. Near-simultaneous thinning of these widely separated glaciers suggests that warming of deeper ocean waters might be a common cause. Nearby glaciers without deep beds are thinning far more slowly, suggesting that basal lubrication as a result of increased surface melting has only a marginal impact on Greenland outlet-glacier acceleration

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