In this project we address the centennial evolution of surface mass balance and in particular meltwater runoff from the Greenland ice sheet (GrIS). GrIS mass loss increased from ~150 Gt yr-1 in 2000-2005, to ~265 Gt yr-1 in 2005-2009 and ~380 Gt yr-1 in 2009-2012, contributing 20-30% to total global average sea level rise over the last decade. An increasingly large fraction of the mass loss (from ~55% in 2000-2005 to ~70% in 2009-2012) is caused by enhanced meltwater runoff. The rapidity of these recent developments is alarming, and we urgently need to address the following questions: how exceptional are recent GrIS surface melt events when viewed in a century-long perspective? What fraction can be ascribed to anthropogenic climate change, and what fraction to natural (decadal) variability? What is the role of transient firn processes and the albedo-melt feedback on meltwater runoff, and how does uncertainty in their representation affect the results? We address these issues by using the ECMWF 20th century global atmospheric re-analysis product, to be released in the summer of 2014, to force -in a fully transient fashion- the coupled regional climate/snow model RACMO2.3. This effort will provide a time series of GrIS surface mass balance, melt and runoff for the period 1900-2014, nearly doubling the length of the currently available time series and enabling us to provide physically-based answers to these pressing questions.

The worldwide shrinking of glaciers and ice sheets represents the largest contribution to current sea level rise. Melting at the glacier-atmosphere interface dominates this mass loss, and will likely do so for centuries to come. To quantify present and predict future melt rates requires the use of high-resolution, state-of-the-art regional atmospheric climate models for Antarctica and Greenland, and distributed surface energy balance (SEB) models for smaller ice caps and mountain glaciers. These models invariably require in situ SEB measurements for evaluation and tuning, which makes dedicated meteorological measurements using automatic weather stations (AWS) invaluable for glacier mass balance research. To that end, UU/IMAU has successfully operated a network of AWS on glaciers in the Alps, Norway, Iceland, Svalbard, Greenland and Antarctica (17 currently operational) since the early 1990s, in close collaboration with international partners. These AWS are specifically designed to close the SEB and quantify melt rate. However, the current AWS design is powered by a relatively large number of lithium batteries and has intricate external wiring, rendering it prone to damage and incompatible with ever-stricter international transportation rules for lithium batteries. Moreover, with this high level of international collaboration, a continuously changing group of researchers and technicians should be able to swiftly deploy and maintain our AWS. In order to overcome these problems, a radically different AWS design is proposed here, the intelligent Weather Station for polar use (iWS). iWS uses ultra-low power consumption sensors and electronics (including datalogger), enabling the full integration of electronics and all but two of the AWS sensors in a single unit (wind speed and radiation remain external). In combination with wireless internal and external data communication, this eliminates the need for vulnerable (external) cables and connectors, and greatly facilitates/shortens AWS installation, maintenance and repair visits. With power consumption reduced by over 95%, only three lithium batteries are required to power an iWs: this saves the environment, enhances transport safety/flexibility and reduces costs. Depending on whether the surface is ablating ice or accumulating snow, an independent, locally powered ultrasonic height sensor or snow thermistor string is installed next to the iWS, which communicate their data wirelessly to the iWS unit through Bluetooth. In melt areas over grounded ice, the iWS is combined with WiSe, a system of up to 32 wireless sensors that transmit englacial temperature and water pressure data through a maximum of 2400 m thick ice. We plan a four-year development, test and transition period (2012-2015) at eight AWS locations. After that, iWS is envisaged to replace all current UU/IMAU AWS.

This project connects a revival of functionalism as a peacebuilding strategy with a reinterpretation of geopolitics focused on urban security. The energy sector has been selected as the main issue area and sphere of action, because energy transition projects for a sustainable society provide great incentives for public/private transnational cooperation. Win-win situations can be created for groups of people who otherwise are stuck in zero-sum conflicts. Such transition projects require a new approach of collecting empirical data for tracing connections between local security complexes and global networks. To this end a business plan will be developed for setting up a Functionalist World Survey Centre. Existing approaches are predominantly state-centric, which produces a national focus on conflict management and peacebuilding in which state security gen-erally trumps human security. A focus on urban security offers a more promis-ing perspective. The geopolitical reality for the majority of the world population is an urbanised world. Moreover, the functioning of urbanised areas is increas-ingly dependent on a critical infrastructure of global networks. By reinterpret-ing geopolitics in terms of urban security insight in new functionalist solutions will emerge. To this end, this project will develop: 1) an academic elaboration of the geopolitics of urban security in a histori-cal context; and 2) a PPP business plan for setting up a Functionalist World Survey Centre for delivering tailor-made micro/macro data for cooperative projects. The results of both will be evaluated during the interdisciplinary Groningen En-ergy Summer School, which in 2016 will be organized for the fifth time.

An estimated 60% of the presently observed sea level rise is attributed to melting glaciers, ice caps and ice sheets. The contribution of Arctic glaciers and especially the Greenland ice sheet (GrIS) has more than doubled over the period 1961-2008, and is likely to increase further when global temperature increases over the coming century. A first order effect of increasing temperatures on the glacier mass budget is an increase in surface melt. However, not all melt contributes to mass loss via runoff, because part of the meltwater refreezes in the cold snow. For the GrIS, an estimated 30-50% of all meltwater refreezes. Infiltration of water and subsequent refreezing is not well included in existing mass balance models, and estimates of refreezing are not well validated due to a lack of observations. Given the importance of refreezing for the mass budget of Arctic glaciers, in this proposal we focus on improving refreezing estimates for the GrIS and therewith other Arctic ice masses, by using a combined observational and modelling approach. Existing satellite and in-situ observations, complemented with detailed snow temperature observations to be carried out in western Greenland (K-transect), will be used to evaluate the mass balance terms and refreezing modelled with the regional climate model RACMO2, which includes a multi-layer snow model. After improvements to the snow model have been implemented and evaluated, RACMO2 will be run for the period 1958-present-2100 in order to study the role of refreezing in the mass balance of the GrIS in a changing climate.