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Melting at the base of the Antarctic Ice Sheet influences ice dynamics and our ability to recover ancient climatic records from deep ice cores. Basal melt rates are affected by geothermal flux, one of the least constrained properties of the Antarctic continent. Estimates of Antarctic geothermal flux are typically regional in nature, derived from geological, magnetic or seismic data, or from sparse point measurements at ice core sites. We analyse ice-penetrating radar data upstream of South Pole revealing a ~100 km long and 50 km wide area where internal ice sheet layers converge with the bed. Ice sheet modelling shows that this englacial layer configuration requires basal melting of up to 6 ± 1 mm a−1 and a geothermal flux of 120 ± 20 mW m−2, more than double the values expected for this cratonic sector of East Antarctica. We suggest high heat producing Precambrian basement rocks and hydrothermal circulation along a major fault system cause this anomaly. We conclude that local geothermal flux anomalies could be more widespread in East Antarctica. Assessing their influence on subglacial hydrology and ice sheet dynamics requires new detailed geophysical observations, especially in candidate areas for deep ice core drilling and at the onset of major ice streams.

The second generation Antarctic magnetic anomaly compilation for the region south of 60°S includes some 3.5 million line-km of aeromagnetic and marine magnetic data that more than doubles the initial map’s near-surface database. For the new compilation, the magnetic data sets were corrected for the International Geomagnetic Reference Field, diurnal effects, and high-frequency errors and leveled, gridded, and stitched together. The new magnetic data further constrain the crustal architecture and geological evolution of the Antarctic Peninsula and the West Antarctic Rift System in West Antarctica, as well as Dronning Maud Land, the Gamburtsev Subglacial Mountains, the Prince Charles Mountains, Princess Elizabeth Land, and Wilkes Land in East Antarctica and the circumjacent oceanic margins. Overall, the magnetic anomaly compilation helps unify disparate regional geologic and geophysical studies by providing new constraints on major tectonic and magmatic processes that affected the Antarctic from Precambrian to Cenozoic times.

The second generation Antarctic magnetic anomaly compilation (ADMAP‐2) for the region south of 60oS includes some 3.5 million line‐km of aeromagnetic and marine magnetic data that more than doubles the initial map's near‐surface database. For the new compilation, the magnetic datasets were corrected for the International Geomagnetic Reference Field, diurnal effects, and high‐frequency errors, and levelled, gridded, and stitched together. The new magnetic data further constrain the crustal architecture and geological evolution of the Antarctic Peninsula and the West Antarctic Rift System in West Antarctica, as well as Dronning Maud Land, the Gamburtsev Subglacial Mountains, the Prince Charles Mountains, Princess Elizabeth Land, and Wilkes Land in East Antarctica, and the circumjacent oceanic margins. Overall, the magnetic anomaly compilation helps unify disparate regional geologic and geophysical studies by providing new constraints on major tectonic and magmatic processes that affected the Antarctic from Precambrian to Cenozoic times.

Understanding the long-term changes in the ice sheets of Greenland and Antarctica has global climate significance, especially on long term global sea level rise predictions. Having validated satellite data on current and recent past changes of the ice sheets are crucial for validating climate and earth system models, and give good opportunities for space geodesy to play an important role for society. Under the ESA Climate Change Initiative two projects on Greenland and Antarctica ice sheet changes are making past and present space measurements of the ice sheets available for use by scientists, stakeholders and the general public. The data are part of a large set of ECV’s (Essential Climate Variables) made available by the ESA Climate Initiative, as a contribution to the global Climate Observing System. The ECV data produced include detailed elevation change data from radar altimetry ice flow velocities from synthetic aperture radar missions, mass changes from GRACE, as well as data of glacier and ice shelf grounding lines and (for Greenland) glacier calving front locations from radar and optical data. In the poster we highlight current CCI results on changes in Greenland, with special focus on 25 year elevation changes from ERS-1, ERS-2, Envisat and CryoSat, as well as the Greenland-wide velocity mapping, and the GRACE mass change results.

A long, unbroken sequence of satellite altimetry elevation changes is an essential climate variable. Here,we present the surface elevation change (SEC) record provided in the ESA Greenland ice sheet CCI project, as 5-year running means spanning back to 1992. The 5-year running mean is chosen to show the imprint of climate change on the Greenland ice sheet surface elevation change and limits the imprint of weather variability. We mainly focus on the novel results from ESA's Cryosat- 2 and the French-Indian SARAL/ALtiKa satellite, as this latest generation of radar altimeters provides new opportunities for monitoring Greenland ice sheet SEC. The orbit of Cryosat-2 enables the generation of a higher temporal-resolution data product from Ku-band radar altimetry; a 2-year running mean SEC. This 2-year product shows the inter-annual variability in weather and its imprint in surface elevation. The observational period of SARAL/ALtiKa satellite has now matured, and an experimental SEC product from Ka-band altimetry is being provided in the Greenland ice sheet CCI. The Kaband radar altimetry is less subject to surface penetration in firn covered areas, and map changes in snowfall in the interior region of the Greenland ice sheet. The Greenland ice sheet CCI now provides 11 maps of Greenland SEC generated from Cryosat-2 or SARAL/ALtiKa data. All giving insight into the complex nature of the changing Greenland ice sheet. The emerging patterns from comparing both Cryosat-2 5- year vs. 2-year SEC and Ku-band vs. Ka-band SEC may relate to the interplay between the surface mass balance and internal ice sheet dynamics.

and relevant to society in connection to sea level rise, fishery, shipping and other off-shore activities (Pugh and Woodworth, 2014). On the other hand, altimetry in coastal areas has proven to be more challenging than over open ocean due to e.g. land footprint contamination and degradation of geophysical corrections (Cipollini et al., 2010; Saraceno et al., 2008; Gomez-Enri et al., 2010). In the last 8 years, ESA's CryoSat-2 (CS2) radar altimetry mission has made a big contribution to coastal altimetry. In fact, it enabled to measure sea surface height closer to the coast than conventional altimeters previously did, using SAR and SAR Interferometric (SARIn) acquisition modes to reduce footprint contamination. This study builds on previous work by Abulaitijiang et al., (2015) and Di Bella et al., (in review) and attempts to estimate sea ice freeboard and thickness using level 1b SARIn data acquired by CS2 along the Western and Northern coasts of Greenland. The challenges and limitations of SARIn altimetry in coastal areas will be identified with the support of airborne and in-situ validation data from the CryoVEx and Operation IceBridge campaigns. References: Abulaitijiang, A., Andersen, O. B., & Stenseng, L. (2015). Coastal sea level from inland CryoSat-2 interferometric SAR altimetry. Geophysical Research Letters, 42(6), 1841-1847. https://doi.org/10.1002/2015GL063131 Cipollini, P., et al. (2010), The role of altimetry in coastal observing systems, in Proceedings of ceanObs'09: Sustained Ocean Observations and Information for Society, Venice, Italy, 21-25 Sept. 2009, vol. 2, edited by J. Hall, D. E. Harrison, and D. Stammer, pp. 181-191, ESA Publ., Noordwijk, Netherlands. Di Bella, A., Skourup, H., Forsberg, R., Uncertainty Reduction of Arctic Sea Ice Freeboard from CryoSat-2 Interferometric Mode. Advances in Space Research- Special Issue on CryoSat- 2, in review. Gomez-Enri, J., Vignudelli, S., Quartly, G.D., Gommenginger, C.P., Cipollini, P., Challenor, P.G.

An accurate coastal geoid model is important for determination of near-shore ocean dynamic topography and currents, as well as for land GPS surveys and global geopotential models. Since many coastal regions across the globe are regions of intense development and coastal protection projects, precise geoid models at cmlevel accuracy are essential. The only way to secure cmgeoid accuracies across coastal regions is to acquire more marine gravity data; here airborne gravity is the obvious method of choice due to the uniform accuracy, and the ability to provide a seamless geoid accuracy across the coastline. Current practice for gravity and geoid models, such as EGM2008 and many national projects, is to complement land gravity data with satellite radar altimetry at sea, a procedure which can give large errors in regions close to the coast. To quantify the coastal errors in satellite gravity, we compare results of a large set of recent airborne gravity surveys, acquired across a range of coastal zones globally from polar to equatorial regions, and quantify the errors as a function of distance from the coast line for a number of different global altimetry gravity solutions. We find that accuracy in satellite altimetry solutions depend very much on the availability of gravity data along the coast-near land regions in the underlying reference fields (e.g., EGM2008), with satellite gravity accuracy in the near-shore zone ranging from anywhere between 5 to 20 mGal r.m.s., with occasional large outliers; such errors may typically propagate into coastal geoid errors of 5-10 cm r.m.s. or more, and highlight the needs for airborne gravity surveys in the coastal zones. One of the first examples of such a dedicated effort is the Azores airborne gravity campaign, carried out more than 20 years ago as part of the AGMASCO (Airborne Geoid Mapping System for Coastal Oceanography) EU project 1996-98.

Studies of the sea level budget are a means of assessing and understanding how sea level is changing and what are the causes. Closure of the total sea level budget implies that the observed changes of global mean sea level as determined from satellite altimetry equal the sum of observed (or otherwise assessed) contributions, namely changes in ocean mass and ocean thermal expansion and haline contraction. Here, ocean mass changes can be either derived from GRACE satellite gravimetry (since 2002) or from assessments of the individual contributions from glaciers, ice sheets, land water storage, snow pack and atmospheric water content. Estimates of thermosteric sea level are obtained from ocean in situ measurements with additional plans for the inclusion of satellite derived Sea Surface Temperature information. Misclosure of the sea level budget indicates errors in some of the components or contributions from missing or unassessed elements in the budget. ESA's Climate Change Initiative (CCI) has conducted a number of projects related to sea level. Among those projects, the Sea Level CCI project, the Greenland and Antarctic Ice Sheet CCI projects and the Glaciers CCI project directly benefit from satellite altimetry data. The Glaciers CCI project and the Sea Surface Temperature CCI project provide additional insights into phenomena related to sea level change. The aim of the ongoing CCI Sea Level Budget Closure project is to use the CCI data products, together with further data products provided by the project partners to re-assess the sea level budget. Specifically, the project further develops and analyzes products based on the CCI projects mentioned above in conjunction with in situ data for ocean thermal expansion (e.g., Argo), GRACEbased ocean mass change assessments, and modelbased data for glaciers and land hydrology. The work benefits from directly involving the expertise on the product generation for all the involved sea level contributions.

For the last eight years, the ESA CryoSat-2 Ku-band radar altimeter has been measuring the elevation of the Greenland Ice Sheet. Ku-band enables surface penetration at firn covered areas, which hampers the direct interpretation of surface elevation change from Cryosat-2 and other Ku-band altimeters. However, mapping the changes in penetration depth can provide information on firn stratigraphy. If the physical surface (snow/air interface) of the ice sheet can be determined from an independent source, the differences in the two surfaces may directly be linked to the penetration depth of Ku-band radar altimetry, and hence to the temperature and density of the upper firn. Here, we use independent estimates of the surface elevation changes from the Ka-band radar altimeter (AltiKa) operated onboard the French/Indian satellite SARAL. The higher frequency of Ka-band reduces surface penetration to a minimum and combining the records from both Ku- and Ka-band satellites are the key to utilizing the full potential of CryoSat-2. Hence, providing both high spatial-resolution surface elevation change and insights into changes in firn properties. The interpretation of dual-frequency altimetry is supported by firn modeling. The model has previously been applied to gain mass balance from ICESat and is now updated with a conceptual model for Ku-band radar penetration. Ultimately, a dual-band radar altimeter operating from space may provide ice sheet wide measurements of firn densities, a key parameter in determining direct ice mass balance from satellite altimetry.

This report outlines the airborne field operations with the ESA airborne Ku‐band interferometric radar (ASIRAS) and coincident airborne laser scanner (ALS) to acquire gridded data over Austfonna ice cap in Svalbard for CryoSat‐2 validation, first direct Sentinel‐3A underflight over sea ice in the Fram Strait and additional repeat some previously flown sea tracks in Fram Strait and the Wandel Sea. Vertical photography was acquired during sea ice flights to support analysis of ASIRAS and ALS observations. The airborne campaign took place April 4‐16, 2016, operating out of Svalbard and StationNord. The campaign was coordinated by DTU Space using the Norlandair Twin Otter (TF‐POF). It was partly funded by ESA CryoVEx (Austfonna ice cap flights) and partly by EU FP7 project ICE‐ARC (Fram Strait and Wandel sea ice flights). The mobilization costs were shared equally between the projects.The CryoVEx/ICE‐ARC 2016 campaign was a success and the processed data is of high quality. Preliminary comparisons between CryoSat‐2 and ALS data at Austfonna ice cap, proves the concept of using a gridded ALS data set of lines parallel to CryoSat‐2 ground tracks in areas with varying topography. First direct comparisons of Sentinel‐3A and ALS also show consistent results.

In preparations for the first CryoSat mission ESA initiated a series of validations campaigns called CryoVEx – CryoSat Validation Experiment. For the first time DTU Space carried out a validation campaign in 2003 and continued in the following years with several pre-launch experiment followed by the first direct validation campaign in spring 2011 after the successful launch of CryoSat-2 in 2010. Since then validation experiments have been carried out both in the Arctic and Antarctic with different instrumental setup. The performance of CryoSat-2 has been validated using an airborne version of the SIRAL altimeter (ASIRAS, manufactured by Radar System Technology) combined with laser scanner altimeter observations together with e.g visual imagery. Also in the very recent campaigns a Ka-band radar system (KAREN) manufactured by MetaSensing has been added to the observations providing the opportunity to collect coincident dual frequency radar altimetry. Combined with in situ observations on ground at selected validations sites, these airborne observations provide a unique dataset of observations coincident in time and space of surface elevations and elevation changes for validation of the CryoSat products. These data have been used for studies that asses the accuracy and error sources of CryoSat-2 (e.g. the CryoVal sea ice and land ice projects). The presentation will give an overview of the airborne campaigns and summarize the main results obtained with the datasets gathered.

What can we learn about the development of public interaction in e-democracy from a drama delivered by mobile headphones to an audience standing around a shopping center in a Stockholm suburb? In democratic societies there is widespread acknowledgment of the need to incorporate citizens’ input in decision-making processes in more or less structured ways. But participatory decision making is balancing on the borders of inclusion, structure, precision and accuracy. To simply enable more participation will not yield enhanced democracy, and there is a clear need for more elaborated elicitation and decision analytical tools. This rigorous and thought-provoking volume draws on a stimulating variety of international case studies, from flood risk management in the Red River Delta of Vietnam, to the consideration of alternatives to gold mining in Roșia Montană in Transylvania, to the application of multi-criteria decision analysis in evaluating the impact of e-learning opportunities at Uganda's Makerere University. Editors Love Ekenberg (senior research scholar, International Institute for Applied Systems Analysis [IIASA], Laxenburg, professor of Computer and Systems Sciences, Stockholm University), Karin Hansson (artist and research fellow, Department of Computer and Systems Sciences, Stockholm University), Mats Danielson (vice president and professor of Computer and Systems Sciences, Stockholm University, affiliate researcher, IIASA) and Göran Cars (professor of Societal Planning and Environment, Royal Institute of Technology, Stockholm) draw innovative collaborations between mathematics, social science, and the arts. They develop new problem formulations and solutions, with the aim of carrying decisions from agenda setting and problem awareness through to feasible courses of action by setting objectives, alternative generation, consequence assessments, and trade-off clarifications. As a result, this book is important new reading for decision makers in government, public a