Final Report Summary - ICEVOLUME (Ice volume changes of Icelandic ice caps in the last 75 years – a view from the air)
Summary description of project objectives: The ICEVOLUME project aimed to quantify the ice volume changes of Icelandic ice caps from the 1930s to the present through time series of Digital Elevation Models (DEMs). The DEMs were produced by stereophotogrammetry on historical aerial photographs. From the project start, we had access to a unique collection of aerial photographs and the new LiDAR DEMs from 2008-2012 that provided us with the necessary raw data for DEM production. Difference DEMs (dDEMs or DoDs) were produced in Geographical Information Systems (GIS) and analyzed together with orthophotographs that visually shows the glacier changes. We aim to interpret the causes of the detected ice cap changes by co-analyzing existing meteorological data, glacier surge records, ice marginal measurements, and other datasets. The project aimed to deliver a 3D view of Icelandic ice cap volume changes through the last c. 75 years. This will significantly advance our current understanding which is mainly based on ice-marginal measurements and point measurements of ablation and accumulation. We have just highlighted the value of similar historical aerial photographs for quantifying ice volume changes over the last century in a study of the Greenland ice sheet (Kjeldsen et al., 2015, published in Nature).
Results of the project so far (December 2015):
During the first three months of ICEVOLUME, some of the raw imagery had to be (re-)scanned on a photogrammetrical scanner in order to ensure a high quality for DEM production. This was unforeseen and time consuming work with a lot of manual tasks. Furthermore, metadata for all aerial photographs to be used in ICEVOLUME were compiled in a database during the first three months. These data include the ground position of image mid-points, flight heading and altitude, and camera information and calibration. The database of Icelandic aerial photographs of glaciers and ice caps is complete together with all metadata needed for digital stereophotogrammetry. We have produced DEMs from 1945-1994 from aerial photographs of a number of Icelandic glaciers and ice caps. Furthermore, we produced DEMs from Aster satellite data. Hands-on training in digital stereophotogrammetry on large blocks of images for DEM production was provided by collaborators at the Natural History Museum of Denmark. During the second half of the first year, we successfully produced the first DEMs from the digitized imagery. We have completed the photogrammetrical work for the major Icelandic ice caps although data analyses are still in progress for some time slices. This work will continue in 2016 although the ICEVOLUME IEF has formally ended. Furthermore, analyses of the oblique images from the 1930s are still going on.
One paper focusing on analyses of DEM timeseries of north Vatnajökull has already been published in Geomorphology (Korsgaard et al., 2015). Using dDEMs from the north margin of Vatnajökull for the years 1961, 1988, and 2003, we quantified the impact of a major glacier surge on the forefield. This kind of quantification of changes in ice volume and sediment volumes is innovative and the paper has been received with large interest and is very frequently downloaded.
One Aster DEM of the Drangajökull ice cap has been successfully produced in collaboration with Oslo University, Norway. The Drangajökull work will be submitted for publication in January 2016 with the working title “Surge characteristics of outlets from the Drangajökull ice cap, northwest Iceland – elevation and volume changes during surges 1994-2011”.
The final data analyses and writing of scientific papers from the ICEVOLUME project will continue in 2016 and we have several additional papers in the pipelines.
Main conclusions so far (December 2015): 1) We successfully produced time series of DEMs of Icelandic ice caps and glaciers from historical aerial photographs. 2) The time series of DEMs were used to extract ice and sediment volume changes at the north margin of the Vatnajökull ice cap (the largest ice cap in Iceland). Here, we documented a net mobilized volume on a 30.7-km2 study area of 34.2 ± 11.3 × 10E6 m3 – mainly in the subglacial environment during the last surge in 1963-64. 3) In a pilot study to be submitted in January 2016, we showed that the DEMs of the Drangajökull ice cap, could be used to quantify the displaced ice volumes during three glacier surges. The study reveals how the ice cap builds up again after surges and how the surged ice volumes melt out in the quiescent phase. 4) We will report further results from the overall analyses of all the DEMs in high-profile scientific publications. Submission is expected in 2016.
Socio-economic impacts of the project: We expected to have produced final DEMs of Difference (DoDs) for the major Icelandic ice caps at the end of the project. The DoDs will allow us to quantify the ice volume changes of the ice caps during the last c. 75 years. As of today, we have produced DEMs of most of the Icelandic ice caps but the data analyses are still in progress as are the drafting of manuscripts for scientific papers. One paper with a pilot study from the Drangajökull ice cap will be submitted in January 2016 (see above). Together with meteorological data and field based glaciological measurements, the DoDs are the key to explain the causes for the ice volume changes and the variation in time and space. Understanding and quantifying recent and sub-recent glacier changes is a key issue in order to be able to predict future response of glaciers to changes in climate and environment. The socio-economic impact of this and similar projects is mainly through quantification of past ice mass loss that has contributed to the observed 20th century sea level rise. This was recently demonstrated in our Nature paper from the Greenland Ice Sheet (Kjeldsen et al., 2015). The Icelandic ice caps do not store comparable amounts of ice mass and do not impact the global sea level to the same scale but might reveal mechanisms and spatial patterns of ice loss through time.
Results of the project so far (December 2015):
During the first three months of ICEVOLUME, some of the raw imagery had to be (re-)scanned on a photogrammetrical scanner in order to ensure a high quality for DEM production. This was unforeseen and time consuming work with a lot of manual tasks. Furthermore, metadata for all aerial photographs to be used in ICEVOLUME were compiled in a database during the first three months. These data include the ground position of image mid-points, flight heading and altitude, and camera information and calibration. The database of Icelandic aerial photographs of glaciers and ice caps is complete together with all metadata needed for digital stereophotogrammetry. We have produced DEMs from 1945-1994 from aerial photographs of a number of Icelandic glaciers and ice caps. Furthermore, we produced DEMs from Aster satellite data. Hands-on training in digital stereophotogrammetry on large blocks of images for DEM production was provided by collaborators at the Natural History Museum of Denmark. During the second half of the first year, we successfully produced the first DEMs from the digitized imagery. We have completed the photogrammetrical work for the major Icelandic ice caps although data analyses are still in progress for some time slices. This work will continue in 2016 although the ICEVOLUME IEF has formally ended. Furthermore, analyses of the oblique images from the 1930s are still going on.
One paper focusing on analyses of DEM timeseries of north Vatnajökull has already been published in Geomorphology (Korsgaard et al., 2015). Using dDEMs from the north margin of Vatnajökull for the years 1961, 1988, and 2003, we quantified the impact of a major glacier surge on the forefield. This kind of quantification of changes in ice volume and sediment volumes is innovative and the paper has been received with large interest and is very frequently downloaded.
One Aster DEM of the Drangajökull ice cap has been successfully produced in collaboration with Oslo University, Norway. The Drangajökull work will be submitted for publication in January 2016 with the working title “Surge characteristics of outlets from the Drangajökull ice cap, northwest Iceland – elevation and volume changes during surges 1994-2011”.
The final data analyses and writing of scientific papers from the ICEVOLUME project will continue in 2016 and we have several additional papers in the pipelines.
Main conclusions so far (December 2015): 1) We successfully produced time series of DEMs of Icelandic ice caps and glaciers from historical aerial photographs. 2) The time series of DEMs were used to extract ice and sediment volume changes at the north margin of the Vatnajökull ice cap (the largest ice cap in Iceland). Here, we documented a net mobilized volume on a 30.7-km2 study area of 34.2 ± 11.3 × 10E6 m3 – mainly in the subglacial environment during the last surge in 1963-64. 3) In a pilot study to be submitted in January 2016, we showed that the DEMs of the Drangajökull ice cap, could be used to quantify the displaced ice volumes during three glacier surges. The study reveals how the ice cap builds up again after surges and how the surged ice volumes melt out in the quiescent phase. 4) We will report further results from the overall analyses of all the DEMs in high-profile scientific publications. Submission is expected in 2016.
Socio-economic impacts of the project: We expected to have produced final DEMs of Difference (DoDs) for the major Icelandic ice caps at the end of the project. The DoDs will allow us to quantify the ice volume changes of the ice caps during the last c. 75 years. As of today, we have produced DEMs of most of the Icelandic ice caps but the data analyses are still in progress as are the drafting of manuscripts for scientific papers. One paper with a pilot study from the Drangajökull ice cap will be submitted in January 2016 (see above). Together with meteorological data and field based glaciological measurements, the DoDs are the key to explain the causes for the ice volume changes and the variation in time and space. Understanding and quantifying recent and sub-recent glacier changes is a key issue in order to be able to predict future response of glaciers to changes in climate and environment. The socio-economic impact of this and similar projects is mainly through quantification of past ice mass loss that has contributed to the observed 20th century sea level rise. This was recently demonstrated in our Nature paper from the Greenland Ice Sheet (Kjeldsen et al., 2015). The Icelandic ice caps do not store comparable amounts of ice mass and do not impact the global sea level to the same scale but might reveal mechanisms and spatial patterns of ice loss through time.