The Age Structure of the Greenland ice sheet from Airborne Radar Data (ASGARD)

Lead Research Organisation: British Antarctic Survey
Department Name: Science Programmes


Recent observations suggest that the Greenland Ice Sheet, is losing ice at an accelerating rate. Because the ice sheet contains 2.85 million cubic km, equivalent to a global sea level rise of 7.2 m, this melting could contribute substantially to future sea level rise. Despite this, current sea level projections specifically exclude changes in the ice flow of the Greenland ice sheet. This is because of difficulties in knowing whether projected changes in the ice sheet are being correctly modelled. Improving the ability to be able to model ice flow dynamics in Greenland is an urgent problem.

To quantify the potential threat that Greenland poses to longer-term global sea-level rise we need a more profound understanding of the internal ice sheet structure. This will help inform how the ice sheet may responses to changing climate.

Airborne geophysics provides a means to observe the internal structure of the Greenland ice sheet. Previously, technical difficulties in extracting information, have prevented the use of existing aerogeophysical data. Here, it is proposed to apply new means to overcome these difficulties. The new methods are based on using techniques which have been developed in other research fields. They will be applied here to this new ice sheet aerogeophysical problem, thereby helping to make the best use of pre-existing expensive aerogeophyscial observations. The new methods will describe quantitatively the internal ages of the ice sheet.

The new age information extracted will allow glaciologists to test, at the continental-scale, whether models of ice flow are correct. This will help to provide a better understanding of ongoing Greenland ice sheet changes, helping to understand the past and predict the future. This is a necessary step in reducing uncertainties on Greenland mass loss predictions.

Planned Impact

Sea level change will have impacts on many international societal issues including land loss, flooding, coastal water supplies and a host of other issues. These impacts mean that policy-relevant information at national and international government level is required. This will be achieved through two routes: (i) The British Antarctic Survey Communications Team will provide plain language, relevant copy for briefing policy-makers. (ii) Several EU ice sheet modelling programmes provides a direct route for proposal scientific results to be included in major policy-relevant programme reports. These programme reports will be directly provided to the UK government.

The techniques and datasets produced by this proposal will be provided to several relevant international programmes. Some of these programmes are based at the British Antarctic Survey, whilst others are run by international collaborators. Impacts on technical radar development proposals are also possible. Scientific knowledge exchanges will be facilitated by a specialist EGU session will be convened. This will be arranged with a range of collaborators.

Dialogue with other stakeholders will be pursued through a variety of means. Routes to impact will include: (i) The highly visited BAS website provides a valuable online communication opportunity. A BAS ASGARD web page will be jointly constructed by the PI and the BAS Communications Team for the BAS website, and additional communications techniques will be used to drive traffic direct to this content. Similar web pages, with links to data resources, will also be supplied to PAGES and, where the PI already maintains web pages. (ii) An ongoing program, talking with school children. (iii) Public talks with the WI, the U3A, and other bodies. (iv) Press releases using engaging, plain language copy will be used to communicate the results and importance of the end of project high impact peer-reviewed paper. This will be co-written by the PI and BAS Communications Team, and used to maximise the potential for media take-up of the findings and ultimate dissemination to the general public. The PI has past experience in successfully writing press releases which have been widely picked up by print, broadcast and online media outlets, communicating key messages throughout. (v) Past experiences in helping to develop features for Planet Earth Online will also be applied to ASGARD.

The impacts of these routes should be to: help foster public understanding of science; facilitate dialogue with children and young people; help secure the next generation of scientists; and reassure the public that the UK remains at the forefront of cutting-edge polar and climate science.

Milestones for impacts will include the publication of, and conference communications of, peer-reviewed papers and datasets. Evaluation of other types of activity will be carried out in accordance with BAS/NERC metrics. The British Antarctic Survey Communications Team already captures outputs from educational and public engagement activity, which are reported annually to the BAS Board and in NERC's RODS database. A brief evaluation report of this project will illustrate how well public engagement objectives are met, and indicate the impact that each has on its target audience. Analysis of impact is conducted through measurement of visitor numbers, media outputs and visitor feedback forms. The BAS Communications Team will also monitor scientific engagement through citation counts, records of articles, programmes, and IPCC citations. As an example of the metrics produced, the BAS website averages 1,800 unique users per day, rising to more than 5,000 when it is used to publish BAS news. BAS press releases generate, on average, 110 media articles giving 19 million opportunities to see, read or hear about the work.


10 25 50
Description Three publications summarise ASGARD grant findings.

Recent accelerations in ice drainage from Greenland and West Antarctica may lead to rapid draw-down in these large ice sheets. Over the longer term these ice-sheet draw-downs will lead to substantial rises in global sea level. We have enabled the assessment of these changes by processing a Greenland airborne radio-echo soundings dataset, covering 500,000km of flight path.

We developed new efficient automatic algorithms, and ran them on a supercomputer. This enabled us to identify regions containing good ice-age data, which can be used to model ice sheet changes. We have shown that good data is present within 36% of the data set, between 1,000 and 3,000m in depth this rises to more than 50%. However we show that in regions where cold ice from 20,000 years ago is present data quality is very poor. This information helps modellers accurately predict future ice sheet changes and correctly model ice-sheet flows.

A second focus of the work was on the climate of Greenland. Measurements of Last Interglacial (126 000 years ago) stable water isotopes in ice cores show that central Greenland d18O increased by at least 3 permil compared to present day. Quantification of Greenland Interglacial temperature change rests on our ability to interpret these stable water isotope observations. By conducting climate simulations using water isotope-enabled general circulation models, and by compiling Last Interglacial sea surface data, we find for the first time a possible explanation for the observed interglacial d18O rise. This helps us constrain past temperature changes over Greenland. We show that a reduction in the winter time sea ice concentration around the northern half of Greenland, together with an increase in sea surface temperatures over the same region, explains the ice core observations. Further we show that sea surface reconstructions lead to the largest uncertainties in interpreting Last Interglacial Greenland temperatures. Finally, we show that further information on Interglacial sea surface temperatures and sea ice changes around northern Greenland will enable us to establish whether a 5oC increase in Last Interglacial temperature, relative to today, is sufficient to drive the observed ice core d18O increase, or whether a larger temperature increases or ice sheet changes are also required to explain the ice core stable water isotope measurements.
Exploitation Route My code has been used by others in the development ice radar science.Ice structure data sets, based on the methods pioneered during the grant, will help enable the evaluation of Greenland ice-sheet models.
Sectors Environment,Other

Description Outreach activities within my Ice and Ice core program have explained how polar geophysical and ice core studies can be used to understand how unique the recent measured changes in the climate and ice sheets are compared with the last 21,000 years. The work has helped demonstrate that ice sheet changes within Greenland, and within British Antarctic Territory, will have an impact on rising sea levels over the coming century. Our briefings have included policy makers: Government Ministers (BIS and FCO) and several MPs; the government Chief Scientist; senior Civil Servants from FCO, BOS, DECC, and the MOD; foreign Ambassadors and Civil Servants. Climate change talks, and tours of the ice core laboratory facilities, have been extended to many senior business leaders from industry, particularly the insurance, energy, automotive and retail sectors, plus independent research organisations with climate change interests. I have also given a variety of schools talk to help encourage our next generation scientists.
First Year Of Impact 2011
Sector Education,Energy,Environment,Government, Democracy and Justice,Manufacturing, including Industrial Biotechology
Impact Types Policy & public services

Title Updated ARESP (Automated Radio-Echo Sounding Processing) algorithms. 
Description An updated automated processing method for obtaining layer dip from Greenland and Antarctic radio-echo sounding (RES) data. The algorithms are presented in MATLAB, which is the standard in this field. Algorithms are robust, applicable, and can be used to process large (several terabyte) ground and airborne RES datasets. The algorithms essentially comprises six basic steps: (1) Noise reduction; (2) Layer identification; (3) Isolating individual layers objects; (4) Measuring dip and associated properties; (5) Error reduction; (6) Collation dip measurements. 
Type Of Material Improvements to research infrastructure 
Year Produced 2012 
Provided To Others? Yes  
Impact Dr Joe MacGregor, at the University of Texas has been working with ARESP code for the past two years. The Center for Remote Sensing of Ice Sheets (CReSIS) is a NSF Science and Technology Center, with the mission of developing new technologies and computer models to measure and predict the response of sea level change to the mass balance of ice sheets in Greenland and Antarctica. Researchers from CReSIS researchers have now also begun to begun to use ARESP algorithms. 
URL http://
Title Surface elevation of 69 Greenland Ice Sheet morphologies and associated d18O anomalies (with respect to Pre-industrial) simulated by HadCM3 
Description The text file (.csv) contains d18O changes simulated at six Greenland deep ice cores (NEEM, NGRIP, GRIP, GISP2, Camp Century and DYE3) from 69 simulations performed using the isotope-enabled HadCM3 climate model forced with mid last interglacial boundary conditions, centred at 125,000 years ago. HadCM3 is used to reproduce the d18O response to 69 modified Last Interglacial (LIG) Greenland Ice Sheet (GIS) morphologies at the ice-core sites. To parameterise the set of 69 GIS morphologies, we undertake a Principal Component Analysis (PCA) approach. The text file also contains the 8PC coefficients for each of the 69 morphologies. The netcdf file (.nc) contains the 8PC shapes and the average shape. To obtain any of the 69 GIS morphologies: (1) store the 8 PC coefficients of a specific GIS morphology and, (2) take a linear combination of the PC shapes (according to those coefficients) and add the average shape. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
Impact Recovery of the past shape/volume of the Greenland ice sheet. 
Description Centre for Ice and Climate, Copenhagen, partnership 
Organisation University of Copenhagen
Department Centre for Ice and Climate
Country Denmark 
Sector Academic/University 
PI Contribution Data processing.
Collaborator Contribution An assessment of CReSIS data by an inhouse Centre for Ice and Climate algorithm
Impact Geophysical Research Letters Publication
Start Year 2012
Description The Center for Remote Sensing of Ice Sheets (CReSIS), University of Kansas partnership 
Organisation University of Kansas
Country United States 
Sector Academic/University 
PI Contribution We contributed new Research Tools, in particular novel and effective automatic processing algorithms.
Collaborator Contribution CReSIS contributed data and expertise to the project (which resulted in a 2014 publication is Geophysical Research Letters).
Impact Publication: Isochronous information in a Greenland ice sheet radio echo sounding data set (2014) Geophysical Research Letters (V: 41, #: 5, Pg.: 1593-1599)
Start Year 2011
Description The Past Earth Network (PEN) 
Organisation University of Leeds
Country United Kingdom 
Sector Academic/University 
PI Contribution Co-leader of the PEN Model-Data comparison group. Myself and my research group will be helping to organise PEN workshops in the coming years.
Collaborator Contribution Organising conference sessions and PhD studentships: earth sciences and statisticians
Impact Conference sessions and PhD studentships: earth sciences and statisticians
Start Year 2015
Description Ice core laboratory tours 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Hands on interaction with ice cores clearly helps engage politicians and policy-maker with our polar science, and helps them understand the multi-faceted nature of climate change.

A notable impact of this activity is the enthusiasm generated for more visits. I believe it also helps encourage politicians to ensure NERC and BAS are adequately funded.
Year(s) Of Engagement Activity 2011,2012,2013,2014