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

2001 ◽  
Vol 47 (156) ◽  
pp. 37-50 ◽  
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.

scholarly journals The contribution of snowdrift sublimation to the surface mass balance of Antarctica

1998 ◽  
Vol 27 ◽  
pp. 251-259 ◽  
Author(s):  
Richard Bintanja
Keyword(s):  
Wind Speed ◽  
Mass Balance ◽  
Surface Mass Balance ◽  
Vertical Profiles ◽  
Sublimation Rate ◽  
Model Calculations ◽  
Surface Mass ◽  
Wind Speeds ◽  
Hourly Data ◽  
Sublimation Rates

This paper presents model calculations of snowdrift sublimation rates for year-round automatic weather station (AWS) data in Terre Adélie, Antarctica. The model calculates vertical profiles of wind speed, temperature, humidity and suspended-snow particles in the atmospheric surface layer, and takes into account the buoyancy effects induced by the stably stratified suspended-snow profile by means of an appropriate Richardson number. The model is able to simulate accurately vertical profiles of sublimation rate derived from direct measurements. The model is used to parameterise snowdrift-sublimation rates in terms of wind speed and air temperature. This parameterisation is then used to calculate snowdrift-sublimation rates from 3 hourly data of six AWSs along a transect from Dumont d'Urville to South Pole during one year. Results show that sublimation of suspended snow is negligible in the interior of Antarctica where wind speeds and temperatures are low, whereas near the windy and relatively warm coast its contribution is significant (up to 17cmw.e. a−1). Snowdrift-sublimation rates are highest during summer, when temperatures are highest, in spite of the fact that wind speeds are not as high as in winter. It is concluded that snowdrift sublimation is one of the major terms in the surface mass balance of Antarctica, in particular in the coastal regions.

scholarly journals How does the ice sheet surface mass balance relate to snowfall? Insights from a ground-based precipitation radar in East Antarctica

2018 ◽  
Vol 12 (6) ◽  
pp. 1987-2003 ◽  
Author(s):  
Niels Souverijns ◽  
Alexandra Gossart ◽  
Irina V. Gorodetskaya ◽  
Stef Lhermitte ◽  
Alexander Mangold ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Clear Understanding ◽  
Surface Mass ◽  
Wind Speeds ◽  
Drifting Snow ◽  
Set Up ◽  
The Antarctic

Abstract. Local surface mass balance (SMB) measurements are crucial for understanding changes in the total mass of the Antarctic Ice Sheet, including its contribution to sea level rise. Despite continuous attempts to decipher mechanisms controlling the local and regional SMB, a clear understanding of the separate components is still lacking, while snowfall measurements are almost absent. In this study, the different terms of the SMB are quantified at the Princess Elisabeth (PE) station in Dronning Maud Land, East Antarctica. Furthermore, the relationship between snowfall and accumulation at the surface is investigated. To achieve this, a unique collocated set of ground-based and in situ remote sensing instrumentation (Micro Rain Radar, ceilometer, automatic weather station, among others) was set up and operated for a time period of 37 months. Snowfall originates mainly from moist and warm air advected from lower latitudes associated with cyclone activity. However, snowfall events are not always associated with accumulation. During 38 % of the observed snowfall cases, the freshly fallen snow is ablated by the wind during the course of the event. Generally, snow storms of longer duration and larger spatial extent have a higher chance of resulting in accumulation on a local scale, while shorter events usually result in ablation (on average 17 and 12 h respectively). A large part of the accumulation at the station takes place when preceding snowfall events were occurring in synoptic upstream areas. This fresh snow is easily picked up and transported in shallow drifting snow layers over tens of kilometres, even when wind speeds are relatively low (< 7 ms−1). Ablation events are mainly related to katabatic winds originating from the Antarctic plateau and the mountain ranges in the south. These dry winds are able to remove snow and lead to a decrease in the local SMB. This work highlights that the local SMB is strongly influenced by synoptic upstream conditions.

scholarly journals Decelerated mass loss of Hurd and Johnsons Glaciers, Livingston Island, Antarctic Peninsula

2013 ◽  
Vol 59 (213) ◽  
pp. 115-128 ◽  
Author(s):  
Francisco J. Navarro ◽  
Ulf Y. Jonsell ◽  
María I. Corcuera ◽  
Alba Martín-Español
Keyword(s):  
Mass Balance ◽  
Total Mass ◽  
Meteorological Conditions ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
The Past ◽  
Mass Losses ◽  
Livingston Island ◽  
Tidewater Glacier ◽  
Observation Period

AbstractA new 10 year surface mass balance (SMB) record of Hurd and Johnsons Glaciers, Livingston Island, Antarctica, is presented and compared with earlier estimates on the basis of local and regional meteorological conditions and trends. Since Johnsons is a tidewater glacier, we also include a calving flux calculation to estimate its total mass balance. The average annual SMB over the 10 year observation period 2002–11 is −0.15 ± 0.10 m w.e. for Hurd Glacier and 0.05 ± 0.10 m w.e. for Johnsons Glacier. Adding the calving losses to the latter results in a total mass balance of −0.09 ± 0.10 m w.e. There has been a deceleration of the mass losses of these glaciers from 1957–2000 to 2002–11, which have nearly halved for both glaciers. We attribute this decrease in the mass losses to a combination of increased accumulation in the region and decreased melt. The increased accumulation is attributed to larger precipitation associated with the recent deepening of the circumpolar pressure trough, while the melt decrease is associated with lower summer surface temperatures during the past decade.

scholarly journals Surface mass balance, thinning and iceberg production, Columbia Glacier, Alaska, 1948–2007

2011 ◽  
Vol 57 (203) ◽  
pp. 431-440 ◽  
Author(s):  
L.A. Rasmussen ◽  
H. Conway ◽  
R.M. Krimmel ◽  
R. Hock
Keyword(s):  
Mass Balance ◽  
Meteorological Data ◽  
Balance Model ◽  
Surface Mass Balance ◽  
Mass Balance Model ◽  
Surface Mass ◽  
Surface Ablation ◽  
Positive Balance ◽  
Remarkable Result ◽  
The Difference

AbstractA mass-balance model using upper-air meteorological data for input was calibrated with surface mass balance measured mainly during 1977–78 at 67 sites on Columbia Glacier, Alaska, between 135 and 2645 m a.s.l. Root-mean-square error, model vs measured, is 1.0 m w.e. a−1, with r2 = 0.88. A remarkable result of the analysis was that both precipitation and the factor in the positive degree-day model used to estimate surface ablation were constant with altitude. The model was applied to reconstruct glacier-wide components of surface mass balance over 1948–2007. Surface ablation, 4 km3 ice eq. a−1 (ice equivalent), has changed little throughout the period. From 1948 until about 1981, when drastic retreat began, the surface mass balance was positive but changes in glacier geometry were small, so the positive balance was offset by calving, ∼0.9 km3 ice eq. a−1 . During retreat, volume loss of the glacier accounted for 92% of the iceberg production. Calving increased to ∼4.3 km3 ice eq. a−1 from 1982 to 1995, and after that until 2007 to ∼8.0 km3 ice eq. a−1, which was about twice the loss by surface ablation, whereas prior to retreat it was only about a quarter as much. Calving is calculated as the difference between glacier-wide surface mass balance and geodetically determined volume change.

scholarly journals Reply to the Comment of Leclercq et al. on "100-year mass changes in the Swiss Alps linked to the Atlantic Multidecadal Oscillation"

2010 ◽  
Vol 4 (4) ◽  
pp. 2587-2592 ◽  
Author(s):  
M. Huss ◽  
R. Hock ◽  
A. Bauder ◽  
M. Funk
Keyword(s):  
Time Series ◽  
Mass Balance ◽  
Atlantic Multidecadal Oscillation ◽  
Swiss Alps ◽  
Surface Mass Balance ◽  
Reference Surface ◽  
Surface Mass ◽  
The Difference ◽  
Opposing Effects

Abstract. In their comment, Leclercq et al. argue that Huss et al. (2010) overestimate the effect of the Atlantic Multidecadal Oscillation (AMO) on the 100-year mass balance variations in the Swiss Alps because time series of conventional balances instead of reference-surface balances were used. Applying the same model as in Huss et al. we calculate time series of reference-surface mass balance, and show that the difference between conventional and reference-surface mass balance is significantly smaller than stated in the comment. Both series exhibit very similar multidecadal variations. The opposing effects of retreat and surface lowering on mass balance partly cancel each other.

scholarly journals On the formation of blue ice on Byrd Glacier, Antarctica

2014 ◽  
Vol 60 (219) ◽  
pp. 41-50 ◽  
Author(s):  
S.R.M. Ligtenberg ◽  
J.T.M. Lenaerts ◽  
M.R. Van Den Broeke ◽  
T.A. Scambos
Keyword(s):  
Mass Balance ◽  
Surface Characteristics ◽  
Ice Formation ◽  
Surface Mass Balance ◽  
Physical Processes ◽  
Surface Mass ◽  
Visual Evidence ◽  
Ice Velocity ◽  
Optical Imagery ◽  
The Difference

AbstractBlue-ice areas (BIAs) cover ~1% of the East Antarctic ice sheet and are visual evidence of persistent ablation. In these regions, more snow is sublimated and/or eroded than is accumulated. The physical processes driving the formation of BIAs are poorly understood. Here we combine a firndensification model with high-resolution (5.5 km) maps of surface mass balance and ice velocity to simulate the build-up and removal of a firn layer along an ice flowline passing Byrd Glacier. A BIA is formed once the complete firn layer is removed. Feedback processes, which enhance blue-ice formation through the difference in surface characteristics of snow and ice, are examined using sensitivity simulations. The presence of blue ice on Byrd Glacier is found to be mainly determined by (1) ice velocity, (2) surface mass balance and (3) the characteristics (thickness, mass) of the firn layer prior to entering the ablation area. With a moderate decrease of the surface mass balance, the location and extent of the simulated BIA on Byrd Glacier is found to be in good qualitative agreement with MODIS optical imagery.

scholarly journals Past and future sea-level change from the surface mass balance of glaciers

2012 ◽  
Vol 6 (4) ◽  
pp. 3177-3241 ◽  
Author(s):  
B. Marzeion ◽  
A. H. Jarosch ◽  
M. Hofer
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Sea Level ◽  
Cross Validation ◽  
Surface Mass Balance ◽  
Rcp Scenarios ◽  
Surface Mass ◽  
The Difference ◽  
Global Surface ◽  
Validation Scheme

Abstract. We present a model of the global surface mass balance of glaciers, based on the reconstruction and projection of the surface mass balance of all the world's individual glaciers. The model is validated using a leave-one-glacier-out cross validation scheme using 3997 observed surface mass balances of 255 glaciers, and against 756 geodetically observed, temporally integrated volume and surface area changes of 341 glaciers. Between 1902 and 2009, the world's glaciers are reconstructed to have lost mass corresponding to 114 ± 5 mm sea level equivalent (SLE). During the 21st century, they are projected to loose additionally between 148 ± 35 mm SLE (scenario RCP26), 166 ± 42 mm SLE (scenario RCP45), 175 ± 40 mm SLE (scenario RCP60), to 217 ± 47 mm SLE (scenario RCP85). Based on the extended RCP scenarios, glaciers are projected to approach a new equilibrium towards the end of the 23rd century, after having lost between 248 ± 66 mm SLE (scenario RCP26), 313 ± 50 mm SLE (scenario RCP45), to 424 ± 46 mm SLE (scenario RCP85). Up until approximately 2100, ensemble uncertainty within each scenario is the biggest source of uncertainty for the future glacier mass loss; after that, the difference between the scenarios takes over as the biggest source of uncertainty. Rates of mass loss are projected to peak between 2050 and 2100, depending on the scenario.

Using ground-penetrating radar to determine the representativeness of ice core surface mass balance records at ice rises along the Princess Ragnhild Coast, East Antarctica

2021 ◽  
Author(s):  
Marie G. P. Cavitte ◽  
Hugues Goosse ◽  
Sarah Wauthy ◽  
Jean-Louis Tison ◽  
Thore Kausch ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ground Penetrating Radar ◽  
Regional Climate ◽  
Ice Core ◽  
Ice Cores ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
The Difference ◽  
Ground Penetrating

&lt;p&gt;Several studies have shown that there is often a poor match between surface mass balance (SMB, mass gain at the surface of the ice sheet) simulated by regional climate models and the one locally measured from ice cores in Antarctica. Models&amp;#8217; representation of the physical processes that affect SMB is known to be imperfect, while ice core records may be strongly influenced by local processes such as post-depositional wind redistribution and precipitation intermittency. These two sources of uncertainty likely both have a role to play in the discrepancy identified between modeled and observed ice core SMB estimates over the past centuries.&lt;/p&gt;&lt;p&gt;The goal here is to estimate the uncertainties associated with the difference between a point-wise measurement of SMB as provided by the ice core and the SMB averages over a grid of several square kilometers of the models. To do so, we use ground-penetrating radar (GPR) data, collected over several ice rises, located along the high accumulation Princess Ragnhild Coast (East Antarctica), to obtain a multi-year resolution record that goes back &amp;#8764;30-40 years, representing SMB spatial and temporal variability at the scale of a few km&lt;sup&gt;2&lt;/sup&gt; for each ice rise. Ice cores were collected during each radar field campaign, which allows us to place age constraints on the radar stratigraphy obtained and compare the GPR SMB estimates with the ice core SMB estimate.&lt;/p&gt;&lt;p&gt;Therefore, we are able to calculate an error of representativeness for each ice core SMB, estimated as the difference between the average GPR SMB over a few km&lt;sup&gt;2&lt;/sup&gt; and the ice core SMB. This representativeness error can be split into two components: a systematic error (on the order of &amp;#8764;0.1 m w.e. yr&lt;sup&gt;-1&lt;/sup&gt;) and a random error (on the order of &amp;#177;1 cm w.e. yr&lt;sup&gt;-1&lt;/sup&gt;). Finally, we then compare our corrected ice core SMB records to regional SMB derived from a state-of-the-art polar-oriented regional climate model to quantify the impact of ice core uncertainties on the modeled-observed SMB discrepancy.&lt;/p&gt;

THE STUDIES OF SURFACE MASS BALANCE AND ICE FLOW ON GLACIERS AUSTRELOVéNBREEN AND PEDERSENBREEN, SVALBARD, ARCTIC

2010 ◽  
Vol 22 (1) ◽  
pp. 10-22 ◽  
Author(s):  
Mingxing Xu ◽  
Ming Yan ◽  
Jiawen Ren ◽  
Songtao Ai ◽  
Jiancheng Kang ◽  
...  
Keyword(s):  
Mass Balance ◽  
Surface Mass Balance ◽  
Ice Flow ◽  
Surface Mass

scholarly journals Reconstruction of historical surface mass balance, 1984–2017 from GreenTrACS multi-offset ground-penetrating radar

2020 ◽  
pp. 1-10
Author(s):  
Tate G. Meehan ◽  
H. P. Marshall ◽  
John H. Bradford ◽  
Robert L. Hawley ◽  
Thomas B. Overly ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ground Penetrating Radar ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Surface Mass Balance ◽  
Snow Density ◽  
Surface Mass ◽  
Age Model ◽  
Ground Penetrating ◽  
Good Agreement

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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