The antarctic ice sheet is the largest reservoir of nonoceanic water mass. Widespread distribution of supraglacial lakes around the. A new nasa study says that antarctica is overall accumulating ice. Supraglacial lakes are important to ice sheet mass balance because their development and drainage has been linked to changes in ice flow velocity. The imbie team has published time series of the mass balance of the greenland and antarctic ice sheets. Two estimates from radar altimeter measurements of. The antarctic ice sheet is an important indicator of climate change and. Overview and assessment of antarctic icesheet mass. Four decades of antarctic ice sheet mass balance from 19792017. The antarctic mass balance is characterized by strong losses from the west antarctic ice sheet wais and the antarctic peninsula ap with trends of. Satellite images reveal huge cracks in antarctic ice sheet. C transect was performed and elaborated using the gipsyoasis ii software 56. Observing and modeling ice sheet surface mass balance lenaerts. The ice sheet mass balance intercomparison exercise imbie is a.
Mass losses of the antarctic ice sheet have increased global sea level by 7. According to the new analysis of satellite data, the antarctic ice sheet showed a net gain of 112 billion tons of ice a year from 1992 to 2001. New images taken by the esas copernicus sentinel satellites shows two major new cracks in the west antarctic ice sheet. It covers about 98% of the antarctic continent and is the largest single mass of ice on earth. Changes in ice dynamics and mass balance of the antarctic. An unweighted average of recent estimates suggests that antarctica moved from a weakly negative mass balance in the 1990s to a faster rate of mass loss at a rate of between 45 and 120 gigatonnes. There is variation between regions within antarctica as can be seen in figure 2. Using a technique developed during work on the greenland ice sheet, the work will significantly improve on prior ice mass estimates made from public global level 2 grace data. Mass balance of the antarctic ice sheet from 1992 to 2017 nature. The mass balance of a glacier is a concept critical to all theories of glacier flow and behaviour. Yet putting all of the terms together to form an accurate estimate of the mass balance of the greenland and antarctic ice sheets has proven complicated. Ice sheet mass balance from remote sensing measurements. Ice sheet modeling of greenland, antarctica helps predict. Map showing the rates of mass changes from icesat 20032008 over antarctica.
Four decades of antarctic ice sheet mass balance from 1979. This chain of events illustrated the vulnerability of ice shelves to climate warming and their buffering role on the mass balance of antarctica. The west antarctic ice sheet and the antarctic peninsula ice sheet are losing a lot of ice mass, at an overall increasing rate. Highresolution modelling of antarctic ice sheet smb. Greenland and antarctic ice sheets european environment. The antarctic ice sheet is one of the two polar ice caps of the earth. It will contribute to solving the problem of antarcticas mass balance by providing a longterm record of elevation changes. The potential for collapse of the antarctic ice sheet remains the largest single source of uncertainty in projections of future sealevel rise. This article is published with open access at abstract mass balance estimates for the antarctic ice sheet ais in the 2007 report by. Best of all, quantarctica is free to download and redistribute. Mass balance of the antarctic ice sheet article pdf available in philosophical transactions of the royal society a mathematical physical and engineering sciences 3641844. Antarctic ice sheet mass gains greater than losses. Owing to gravitational forces, the melting of the antarctic ice sheet contributes more to sea level rise in the northern hemisphere than the melting of the greenland ice sheet.
Her research focuses on assessing uncertainties in ice sheet model projections, particularly on the greenland and antarctic ice sheets. Mass balance of the greenland ice sheet from 1992 to 2018 nature. Greenland than it is for antarctica, reflecting differences in ice sheet size. Request pdf mass balance of the antarctic ice sheet from 1992 to 2017 the antarctic ice sheet is an important indicator of climate change and driver of sealevel rise. Marshall 3 1centre for polar observation and modelling, university college london, gower street, london wc1e 6bt, uk 2centre for polar observation and modelling, scott polar research institute, university of cambridge, lens. Mass balance of the antarctic ice sheet from 1992 to 2017.
Quantarctica is a collection of antarctic geographical datasets which works with the free, crossplatform, opensource software qgis. Progress in numerical modeling of antarctic icesheet. Research ice sheets and climate university of colorado. We evaluate the state of the mass balance of the antarctic ice sheet over the last four decades using a comprehensive, precise satellite record and output products from a regional atmospheric climate model to document its impact on sealevel rise. We evaluate the state of the mass balance of the antarctic ice sheet over the.
Recent advances in the determination of the mass balance of polar ice sheets show that the greenland ice sheet is losing mass by nearcoastal thinning, and that the west antarctic ice sheet, with thickening in the west and thinning in the north, is probably thinning overall. The observation program was carried out in the fall of 2007 and the spring of 2009 during a drift program of the nathaniel b. Ice thickness and more in sea ice mass balance in the. Mass balance of the antarctic ice sheet from 1992 to 2017 request. Icesat2 will measure changes in the antarctic ice sheet within the thickness of a no. The antarctic ice sheet is the largest single mass of ice on earth. An introduction to glacier mass balance antarctic glaciers.
Launched january 12, 2003, nasas ice, cloud, and land elevation satellite, or icesat, is designed to measure the mass balance of earths ice sheets balance between processes that add ice to the ice sheets versus processes that remove ice, the height of clouds and aerosols, and the topography of the land. The antarctic ice sheet is an important indicator of climate change and driver of sealevel rise. The mass imbalance of the east antarctic ice sheet is likely to be small, but even its sign cannot yet be determined. This is a significant, but small, proportion of the total antarctic ice loss determined by grace see figures in john cooks summary above.
This uncertainty comes from an imperfect understanding of ice sheet processes and the internal variability of climate forcing of ice sheets. Introduction 2 assessment of antarctic mass balance is an essential element in understanding past and present changes in global mean sea level and climate, and in understanding present variations in the global hydrological cycle, ocean temperature, salinity, ocean general circulation, atmospheric dynamics, and other problems. Several drilling programs have used a multiparameter approach for assessment. Mass flux measurements across the margin of the antarctic ice sheet metadata record for data from asac project 2318 see the link below for public details on this project. There are around 7 metres of potential sealevel rise locked up in the greenland icesheets and 57 metres in the antarctic icesheets. Ice losses from antarctica have tripled since 2012, according to a comprehensive survey by scientists from all over the world. However, predicting the expected loss of ice sheet mass. Consequently these products will be produced by the cci antarctic ice sheet project over the next three years. It covers an area of almost 14 million square km and contains 30 million cubic km.
A german supply ship close to a vast ice shelf along the coastline of the west antarctic ice sheet press release issued. A cubic kilometer of ice weighs approximately one metric gigaton. Increases in ice loss from the glaciers of antarctica, greenland, and the rest of the arctic are contributing to sea level rise, while similarly dramatic changes are occurring in the sea ice cover of the arctic and southern oceans. What is the surface mass balance of the antarctic ice sheet. Antarctic ice sheet surface mass balance antarctic glaciers.
Palmer icebreaker along with a buoy network established on the antarctic sea ice. Surface mass balance contributions to acceleration of. An increased rate of mass loss results in a faster rise in the global mean sea level. A glacier is the product of how much mass it receives and how much it loses by melting. Here are some facts about the planets single biggest ice mass, and why it is so important to the planet. Overview and assessment of antarctic icesheet mass balance estimates.
Surprising facts about the antarctic ice sheet seeker. In this work, we aim to map the antarctic ice sheet ais surface mass balance smb at an unprecedentedly high resolution 1 km, using a unique combination of elevation data derived from radar and laser altimetry cryosat2 and icesat2, atmospheric reanalyses, and icebridge radar data. The 300 gtyear range is approximately 15% of the annual mass input and 0. The mass of the antarctic ice sheet has changed over the last several years. Ar4 was considerably more candid than ar5 about the continuing impact of the end of the last ice age. The mass loss is dominated by enhanced glacier flow in areas closest to warm, salty, subsurface circumpolar deep water, including east antarctica. Antarctic ice sheet mass loss has increased eurekalert. Mass flux measurements across the margin of the antarctic. The data are somewhat challenging to ingest into standard software packages, but. Research ice sheets and climate university of colorado boulder.
Here we combine satellite observations of its changing volume, flow and gravitational attraction. Highresolution mass trends of the antarctic ice sheet. This not only required substantial software development, including allowing for. Spatial and temporal antarctic ice sheet mass trends. Imbie greenland and antarctic datasets european environment. Mass gains of antarctic ice sheet greater than losses. The expert group on ice sheet mass balance and sea level ismass is cosponsored by the scientific committee on antarctic research, the international arctic science committee iasc, and the wcrp climate and cryosphere project. The east antarctic ice sheet has grown slightly over the period shown. The sum of the changes from all basins, figure 2a, is an antarctic total mass variation time series from january 2003 to december 20. Mass balance, ice velocity, surface elevation change and grounding lines were determined to be the most important data products. Public summary from project this project is a cooperative venture between australian and italian institutes in a study of the mass budget of a large sector of the. It covers an area of almost 14 million square kilometres 5.
Measurements of ice thickness, temperature profiles, largescale deformation, and other sea ice characteristics were made. Abstract 1245788simons this award supports a project to undertake an accurate and robust spatial and temporal assessment of the mass flux in the antarctic region from the data collected by the grace satellites. Using a mathematical technique from statistical physics and large ensembles of stateoftheart ice sheet. Research based on observations from nasas twin nasagerman aerospace centers twin gravity recovery and climate experiment grace satellites indicates that between 2002 and 2016, antarctica shed approximately 125 gigatons of ice per year, causing global sea level to rise by 0. We use 26 estimates of ice sheet mass balance derived from satellite altimetry. Still, areas of the continent, like the antarctic peninsula photographed above, have increased their mass loss in the last decades. State of antarctic and greenland ice sheet mass balance.
The mass balance of a glacier or ice sheet is the net balance between the mass gained by snow deposition, and the loss of mass by melting either at the glacier surface or under the floating ice shelves or ice. The goals of ismass are to promote the research on the estimation of the mass balance of ice sheets and its contribution to sea level, to facilitate the coordination. Imbie is a collaboration between scientists supported by the european space agency and the national aeronautics and space administration, and contributes to assessment reports. The ice sheet mass balance intercomparison exercise imbie was established in 2011 as a community effort to reconcile satellite measurements of ice sheet mass balance. Ice sheet massbalance estimates for greenland and antarctica. State of antarctic and greenland ice sheet mass balance and icesheet modeling richard b. She is also responsible for integration and testing of the issm glacier energy and mass balance gemb surface module that simulates the evolution of the ice sheet surface radiation balance and firn densification. Assessment of the data and techniques suggests overall antarctic ice sheet mass balance ranging from growth of 50 gt yr1 to shrinkage of 200 gt yr1 from 1993 to 2003. That net gain slowed to 82 billion tons of ice per.
The greenland and antarctic ice sheets will make a dominant contribution to 21st century sealevel rise if current climate trends continue. The mass balance of a glacier is a measure of its health, reflecting the balance between the amount of snow that accumulates on the glaciers. To predict how the ice sheets mass balance might change in the future, scientists must understand the current mass balance of the antarctic ice sheet, along with the factors that influence it. Pronounced regional warming in the antarctic peninsula triggered ice shelf collapse, which led to a 10fold increase in glacier flow and rapid ice sheet retreat. That net gain slowed to 82 billion tons of ice per year between 2003 and 2008. We use 26 estimates of ice sheet mass balance derived from satellite.