See animations of satellite images of major outlet glaciers of the greenland ice sheet. Lining the two graphs up side by side, you can see the more than one trillion tons of ice which greenlands surface has. Each year, the ice sheet gains ice from snowfall and loses ice through iceberg calving and surface melting. Surface mass balance of the grounded antarctic ice sheet is currently estimated at 2000 gigatonnes per year 2, 5, 6, and it is subject to large variability across the ice sheet and through time. Feb 05, 2020 fortysix years of greenland ice sheet mass balance from 1972 to 2018. We reconstruct the mass balance of the greenland ice sheet for the past 46 years. An integrated view of greenland ice sheet mass changes. Surface processes currently dominate greenland ice sheet gris mass loss.
The response of the greenland ice sheet gris to a warmer climate is. Current ice margin recession is led by the retreat of outlet glaciers, large rivers of ice ending in narrow fjords that drain the interior. Esm and find minor cooling over the greenland ice sheet and barents and. Higher surface mass balance of the greenland ice sheet. The mass balance of the greenland ice sheet gris has changed significantly over the last two decades. This detailed knowledge of greenland s surface mass balance provides the foundation for estimating and predicting the overall mass balance and freshwater discharge of the ice sheet. We have reconstructed the recent 18662005 surface massbalance smb history of the greenland ice sheet on a 5 5km grid. From 2002 to 2009, the rate of ice mass loss doubled. Mass balance of the antarctic ice sheet from 1992 to 2017. The program for arctic regional climate assessment produced several. The greenland ice sheet is about the same size as the state of. Although increases in glacier flow46 and surface melting79 have been.
Fortysix years of greenland ice sheet mass balance from 1972 to 2018. Greenlands ice mass balance not a lot of people know that. A low climate threshold for south greenland ice sheet demise. For this reason, there tends to be differences between the results of different techniques used to measure surface mass balance. Apr 09, 2020 the greenland ice sheet is a vast body of ice covering roughly 80% of the surface of greenland. What is the global volume of land ice and how is it. Greenland ice sheets 2017 weighin suggests a small increase. Greenland melting scam crashes and burns real climate. Scientists confirm dramatic melting of greenland ice sheet. The modeling of ice sheets in earth system models esms is an active area. Reconstruction of the greenland ice sheet surface mass balance. The mass balance of greenland has been increasingly negative since 1995, and it is now equivalent to the global contribution to sea level rise from glaciers and ice caps figure 2.
The left maps shows total snowfall and rainfall, if any, minus runoff or evaporation, which is the surface mass balance smb for the greenland ice sheet. Glacier surface mass balance is measured as the height change between the surface and a coordinate system fixed relative to the ice beneath. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. Decreasing cloud cover drives the recent mass loss on the. This was especially true over over its west and southwest regions. Follow the total mass balance of the greenland ice sheet and its contribution to global sealevel. Overall greenland is losing ice mass at an accelerating rate. Here we examine the simulation of greenland ice sheet surface mass balance gris smb in the nasa goddard institute for space studies giss modele2 general circulation model gcm. Estimating the greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model mar. While the greenland interior is in mass balance, the coastlines are losing ice. Greenland gains huge amounts of ice for the second year in a. Greenland ice sheet surface mass balance variability 1988. A major challenge for surface mass balance smb modeling with esms.
Aug 31, 2018 last year greenland gained a little more ice, about 50% above normal. Reconstruction of the greenland ice sheet surface mass. Contribution of the greenland ice sheet to sea level over the. The model was initialized and constrained by available observations, e. The surface mass balance smb of the greenland ice sheet gris can be approximated in. In the first ice sheet mass balance intercomparison exercise imbie, 2, the. The greenland ice sheet has been a major contributor to global sealevel rise in recent decades 1,2, and it is expected to continue to be so 3. Quantifying the past, present and future state of smb is important to understand the drivers and climatic processes to control smb, and to both initialize and run ice sheet models which will help clarify sea level rise, and how likely changes in ice sheet extent feedback within the climate system. Changes at the ice sheet surface also feedback to influence future melt e. Surface mass balance takes into account gains in the ice sheet s mass such as through snowfallas well as losses from surface meltwater runoff. Surface mass balance smb is the builder of the greenland ice sheet and the driver of ice dynamics. The insignificance of greenlands ice mass loss in five. Meteorological station records, ice cores, and regional climate model output are combined to develop. The snow and ice model from one of dmis climate models is driven every six hours with snowfall, sunlight and other parameters from a research weather model for greenland, hirlamnewsnow, and since 1 july 2017 the harmoniearome weather model.
A surface mass balance model for the greenland ice sheet. The insignificance of greenlands ice mass loss in five easy. At some locations, the ice sheet surface decreased by over two and a half metres per year between 1995 and 2017 based on measurements using spaceborne radar altimeters. Surface massbalance changes of the greenland ice sheet since. Higher surface mass balance of the greenland ice sheet revealed by highresolution climate modeling jannekeettema,1 michielr. Observing and modeling ice sheet surface mass balance lenaerts. Modele climate simulations simulated greenland surface mass balance in the giss modele2 gcm. Regional climate model and ice sheet model simulations show that surface mass.
Unusually clear skies drove record loss of greenland ice. Here you can follow the daily surface mass balance on the greenland ice sheet. Lining the two graphs up side by side, you can see the more than one trillion tons of ice which greenland s surface has. The surface mass balance, one of the major components of surfaceinduced elevation. Research ice sheets and climate university of colorado boulder. Direct observations of the greenland ice sheet from fall 2018 through 2019 reveal another year of dramatic ice loss. Oct 23, 2016 wu et al 2010 use a new method to calculate ice sheet mass balance. In this thesis, we develop, validate and apply a physics based numerical model to estimate current and future surface mass balance of the greenland ice sheet.
You can compare the updated images with the positions of the glaciers in the mid1980s and in the year 2000. Importance of the ice sheet surface by alexander et al. Contract nnxai84 a with the nasa cryosphere science program. Sermersuaq is a vast body of ice covering 1,710,000 square kilometres 660,000 sq mi, roughly 94% of the surface of greenland it is the second largest ice body in the world, after the antarctic ice sheet. The extent and magnitude of ice loss rival 2012, the previous record year of ice loss. Greuell 2005, a surface mass balance model for the greenland ice sheet, j. Sep 14, 2017 unusual weather conditions in 2017including a blizzard caused by the remnants of 2016s hurricane nicole and a short surface melt seasonare behind preliminary estimates of a small gain in ice mass on the greenland ice sheet this year. Almost all of the ice loss was due to changes in surface mass budget, with thinning found virtually everywhere. In the latter study, for a 12year period 19881999, there was some evidence that larger runoff is associated with lower accumulation. The data are somewhat challenging to ingest into standard software packages, but. Gcms are often limited in their ability to represent smb compared with polar region regional climate models. Ice sheet mass balance from remote sensing measurements. Ice sheet massbalance estimates for greenland and antarctica. Greenland s ice sheet is seven times the area of the uk and up to 23km thick in places.
The term surface mass balance is used to describe the isolated gain and loss of mass of the surface of the ice sheet excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater. This directory contains a data supplement to the journal article simulated greenland surface mass balance in the giss modele2 gcm. The surface mass balance was nearly negative in 1998 26 km 3 yr. The map illustrates how the surface of the greenland ice sheet gains and loses mass on a daily basis. Research shows how glacier algae creates dark zone at the. During the 21st century, loss of mass from the greenland ice sheet in response to anthropogenic climate change is ex. Greenland ice sheet today surface melt data presented by nsidc. Although, it does not agree well with most other measurement techniques, wu et als 2010 estimate is still at the upper end of ipcc predictions for ice losses and shows extensive land ice losses from both antarctica and greenland. The rate of growth or retreat of the greenland and antarctic ice sheets remains a highly uncertain component of future sea level change. It is a cheap and simple alternative to arduous fieldwork, but ground truthing of mass balance measurements will always be necessary. Greenland ice sheet today surface melt data presented by. Estimation of the greenland ice sheet surface mass balance. Greenland ice sheets 2017 weighin suggests a small.
The numerical model consists of a coupled surface energy balance and englacial. Here, we simulate the greenland ice sheet gris surface mass. More than a mile thick in places, the greenland ice sheet is so large that it would cover the gulf of mexico and spill over onto the shores of the gulf coast states. The simulations are designed to evaluate the modele2 simulation of greenland ice sheet. This graph shows the total surface mass balance smb for the greenland ice sheet from september 2018 to august 2019, relative to the 1981. We pair an outlet glacierresolving ice sheet model with a comprehensive uncertainty quantification to estimate. The calving loss is greater than the gain from surface mass balance, and greenland is losing mass at about 200 gtyr. New greenland ice sheet annual surface mass balance smb1 series from 1870 to 2010, extended and recalibrated from hanna et al. Fortysix years of greenland ice sheet mass balance from 1972 to. Clear skies drove the biggestever drop in greenlands ice. Greenland surface massbalance observations from the icesheet ablation area and local glaciers. Examples of surface mass balance from the polar portal website a daily surface mass balance of greenland in mm day1.
Greenland ice sheet surface massbalance modeling in a 1yr perspective, 19502080. Fortysix years of greenland ice sheet mass balance from. Yet, surface mass balance that is, the net balance between ice gains from snowfall and ice loss through melt was the lowest on record during. Since ipcc ar5, our understanding of gris smb has further improved, but new observational. Models suggest a possible temperature threshold between 0. The near coincidence of the ice acceleration with the duration of surface melting, followed by deceleration after the melting ceases, indicates that glacial sliding is enhanced by rapid migration of surface meltwater to the ice. A set of experiments designed to investigate the role of sea ice independently from sea surface temperature sst forcing are described. The geoscience laser altimeter system glas instrument on the ice, cloud, and land elevation satellite icesat provides global measurements of polar ice sheet elevation to discern changes in ice volume mass balance over time. Pdf greenland ice sheet surface massbalance modeling in. Animation of daily surface mass balance over the greenland ice sheet in 20152016 via. The ocean is simulated with the parallel ocean program 2 pop2. Mar 20, 2018 over the year, it snows more than it melts, but calving of icebergs also adds to the total mass budget of the ice sheet. Simulated greenland surface mass balance in the giss. Oct 29, 2018 the end of august traditionally marks the end of the melt season for the greenland ice sheet as it shifts from mostly melting to mostly gaining snow.
Examples of surface mass balance from the polar portal website a daily surface mass balance of greenland in mm. Range weather forecasts meteorological reanalysis tuned against the bales et al. Here we examine the simulation of greenland ice sheet surface mass balance gris smb in a development branch of the modele2 version of the nasa goddard institute for space studies giss general circulation model gcm. An introduction to glacier mass balance antarctic glaciers. Greenland gains huge amounts of ice for the second year in. We reconstruct the mass balance of the greenland ice sheet for the past 46 years by comparing glacier ice discharge into the ocean with interior accumulation of snowfall from regional atmospheric climate models over 260 drainage basins. The mass balance started to deviate from its natural range of variability in the 1980s.
A study published in 2020 estimated, by combining 26 individual estimates of mass balance derived by tracking changes in greenland s ice sheet volume, speed and gravity as part of the ice sheet mass balance intercomparison exercise, that the greenland ice sheet had lost a total of 3,902 gigatons gt of ice between 1992 and 2018. Surface height change is typically measured in successive end of summer or winter balance years, rather than for calendar years, and are typically made along elevation profiles e. Higher surface mass balance of the greenland ice sheet revealed by highresolution climate modeling. The daily surface mass balance smb of the ice sheet is also presented and compared with the long term average to indicate what the ice sheet surface mass balance weather is doing today. We thank all the scientists, software engineers, and administrators who. It stores so much frozen water that if the whole thing melted, it. The binary data subsetter also has been decommissioned. Jul 12, 2002 ice flow at a location in the equilibrium zone of the westcentral greenland ice sheet accelerates above the midwinter average rate during periods of summer melting. We use 26 estimates of ice sheet mass balance derived from satellite. Related content evaluating greenland glacial isostatic adjustment corrections using grace, altimetry and surface mass balance data tyler c sutterley, isabella velicogna. The surface mass balance, the amount of ice the sheet gained from rain and snowfall minus the amount lost through meltwater run off and evaporation, was just 54gt a year about 320gt a year. This not only required substantial software development, including allowing for solid ice discarge into.
Since ipcc ar5, our understanding of gris smb has further improved, but new. Earths ice sheetsthe greenland ice sheet gris in the arctic and the antarctic ice sheet. Surface energy and mass balance model for greenland ice sheet. They found 2019 was one of the worst years on record, which saw the greenland ice sheet s surface mass balance drop by about 320 billion tons, below the. The modeling of ice sheets in earth system models esms is an active area of. It is the second largest ice body in the world, after the antarctic ice sheet.
The trajectories were very different last year and this year, but the final result was about the same. Although increases in glacier flow 4,5,6 and surface. Dec 10, 2019 the greenland ice sheet has been a major contributor to global sealevel rise in recent decades 1,2, and it is expected to continue to be so 3. Abstract fluctuations in the greenland ice sheet gris surface mass balance. If it melts completely, it will raise the height of the ocean surface by 20 feet 6 meters. Aug 27, 2018 remote sensing data, surface observations and models indicate new records in 2010 for surface melt and albedo, runoff, the number of days when bare ice is exposed and surface mass balance of the greenland ice sheet. The greenland ice sheet s surface mass balance in a. Jun 16, 2009 the absolute increase in runoff is especially pronounced in the southeast, where several outlet glaciers have recently accelerated. Pdf a surface mass balance model for the greenland ice sheet.
After quantifying the full suite of pigments produced by glacier algae and modelling their growth on the surface of the greenland ice sheet surface, the teams next step is to incorporate all of. Surface mass balance of the greenland ice sheet simulated. Greenland ice sheet surface mass balance data the polar mm5 regional climate model was run over greenland in a series of 36hour forecasts spanning 19912000 box et al. Smb spans from september 2018 to august 2019, shown in number of millimeters 0.
Last year greenland gained a little more ice, about 50% above normal. Projected future melt of the greenland ice sheet may be. Modeled spatial and temporal wet zone extent compares well with information derived from passive microwave satellite data. Here, we simulate the greenland ice sheet gris surface mass 30 balance smb, including refreezing and retention, and runoff together with catchment scale 31 runoff from the entire greenland landmass n 3,27 2 simulated catchments throughout the 35 32 year period 1979 2014. Satellite observations over the last decade show that the ice sheet is not in balance. Sea ice model documentation and software users manual version 4. Greenland surface massbalance observations from the ice. Estimating the greenland ice sheet surface mass balance. You can see the mass balance in greenland as your bank. The noncommencement of the thaw in greenland at the end of may is without precedent in past years, at least since 1990. Highresolution ice sheet surface mass balance and spatiotemporal runoff simulations. Roughly 95% of the greenland ice sheet surface underwent melting. Cumulative ice mass loss from greenland ice sheet 19922012 1 from ipcc ar5.
Using three regional climate models, we show that reduced surface mass balance has driven 1,971 555 billion tonnes 52% of the ice loss. Mass balance of the greenland ice sheet from 1992 to 2018. The 19002100 greenland ice sheet surface mass balance fig. Meteorological station records, ice cores, and regional climate model output are combined to develop a continuous 171yr 18402010 reconstruction of greenland ice sheet climatic surface mass balance b clim and its subcomponents including nearsurface air temperature sat since the end of the little ice age. However, since then, mass loss has accelerated as the surface mass balance smb has declined and d has increased. Mass loss from the greenland ice sheet over the past decade has caused the impression that the ice sheet has been behaving anomalously to the warming of the 1990s. Greenland s ice sheet, the worlds second largest, recorded its biggest outright drop in what scientists call surface mass since recordkeeping began in 1948, according to the study. Researchers from aberystwyth university use satellite measurements to track changes in the mass balance of the greenland ice sheet. Greenland ice sheet surface massbalance modeling in a 1yr. Media playback is unsupported on your device media captionwhy is antarcticas mighty thwaites glacier melting. Surface meltinduced acceleration of greenland icesheet flow. Hemisphere total snow mass off to a record start september 23, 2019 september 23, 2019 cap allon on the back of substantial surface mass balance smb gains over the past few years, the greenland ice sheet looks set to continue that trend in 201920. Until the mid1990s, losses from surface meltwater runoff and ice discharge into the ocean d were roughly balanced by snow accumulation 1, 2.
The duration of warmth above a given threshold is also a critical determinant for gis survival, underlining the role of ocean. Greenland ice sheet surface mass balance 1870 to 2010. The simulations are designed to evaluate the modele2 simulation of greenland ice sheet surface mass balance, and evaluate the impact of. Overall, the greenland ice sheet lost an estimated 600 billion tons in 2019, representing a sea level rise of about 1. Greenland and antarctica ice loss accelerating news. Although increases in glacier flow46 and surface melting79 have been driven. To derive surface mass balance and runoff, mote 2003 employed a. Greenland ice sheet surface mass balance research papers. Jan 07, 2020 the greenland ice sheet gis has been losing mass at an accelerating rate over the recent decades. The surface mass balance, the amount of ice the sheet gained from rain and snowfall minus the amount lost through meltwater run off and evaporation, was just 54gt a. To investigate the impact of this phenomenon on greenland ice sheet climate and surface mass balance smb, a regional climate model, hadrm3, was used to force an insolationtemperature melt smb model. Surface mass balance downscaling through elevation classes.
View greenland ice sheet surface mass balance research papers on academia. Mass balance of the greenland ice sheet from 1992 to 2018 nature. This method, like all new methods will improve and be revised with time. The ice sheet is almost 2,900 kilometres 1,800 mi long in a northsouth direction, and its greatest width is 1,100. Earths great ice sheets, greenland and antarctica, are now losing mass six tim.