3,603 research outputs found

    Ablation observations for 2008–2011 from the Programme for Monitoring of the Greenland Ice Sheet (PROMICE)

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    Recent estimates from the glaciological community agree that the Greenland ice sheet is losing mass at an accelerated pace due to climate change (Velicogna 2009; Khan et al. 2010; Rignot et al. 2011). This has caught the attention of the public and policy makers due to the potential impact on sea-level rise (Dahl-Jensen et al. 2009). The mass loss can be attributed approximately equally to increases in meltwater runoff from surface melt and iceberg production (van den Broeke et al. 2009)

    Programme for Monitoring of the Greenland Ice Sheet (PROMICE): first temperature and ablation records

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    The Greenland ice sheet is reacting to climate change. Yet, mass-budget estimates differ considerably, partly due to climatic variability and partly to uncertainties in the techniques of assessing mass change (IPCC 2007). Nevertheless, all recent estimates agree that the ice sheet is losing mass (e.g. 286 Gt/yr; Velicogna 2009) at an accelerating rate (Rignot et al. 2011). On top of this, the area with a negative mass budget is expanding rapidly (Khan et al. 2010). The mass loss is attributed equally to increases in both iceberg production and melting of the ice sheet (Van den Broeke et al. 2009). The increasing mass loss in recent years has caught public attention and given rise to concern worldwide due to its potential impact on sea level. In the light of this, the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) was initiated in 2007 (Ahlstrøm & PROMICE project team 2008), lead by the Geological Survey of Denmark and Greenland (GEUS). PROMICE undertakes surface mass-budget measurements using automatic weather stations, quantifies the mass loss by iceberg calving using remotely sensed data from satellites and airborne surveys and tracks changes in the extent of glaciers. In this paper, we focus on weather station measurements, which are crucial in calculating the energy exchange between the atmosphere and the ice sheet, and in validating model calculations of the surface mass budget. In particular, we present the observed temperatures and investigate how their high 2010 values affected ablation in southern Greenlan

    Climate Change Adaptation Policy in Ghana: Priorities for the Agriculture Sector

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    This report is intended to complement the 2011 CCAFS publication “State of Climate Change Adaptation and Mitigation Efforts for Agriculture in Ghana” (Domozoro 2011). It provides relevant updates regarding the policies, projects, or initiatives introduced therein, and an assessment of the evolving political scenario. Specifically, this document presents an objective look at 17 key policy documents within three thematic areas: (1) governance, (2) agriculture, and (3) climate change institutions in Ghana. Several key projects are also included in this analysis given their relevance and status within Ghana’s agricultural adaptation regime. A discussion of the institutional arrangements in each of the thematic areas is provided first, along with a short description of each of the 17 policies and projects. Then, in the following analysis section, objectives and priorities for each of the policies are outlined, together with their evolution over time, intending to identify the temporal shifts in agricultural climate change policy direction in the country. Policy interplay between and within these thematic areas is also addressed. Power and influence dynamics between actors in Ghana’s climate change adaptation regime are discussed in the following section and the results of a Multilevel Stakeholder Influence Mapping (MSIM) exercise are provided. Finally, a discussion of key challenges and recommendations are provided, as identified through semi-structured interviews with actors across the country’s adaptation regime

    User Identification Using Games

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    There is a significant shift towards a digital identity and yet the most common means of user authentication, username and password pairs, is an imperfect system. In this paper we present the notion of using videogames, specifically Tetris, to supplement traditional authentication methods and provide an additional layer of identity validation. Two experiments were undertaken that required participants to play a modified version of Tetris; the first experiment with a randomly ordered set of pieces and the second with the pieces appearing in a fixed order. The results showed that even simple games like Tetris demonstrate significant complexity in the available game states and that while some users displayed repeatable strategic behaviour, others were effectively random in their behaviours exhibiting no discernible strategy or repeatable behaviour. However, some pieces and gameboard scenarios encouraged users to exhibit behaviours that are more unique than others

    Animal attacks – a red herring of child abuse?

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    No Abstract. South African Medical Journal Vol. 96 (3) 2006: 184-18

    Katabatic winds and piteraq storms: observations from the Greenland ice sheet

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    In 2007 the Programme for Monitoring the Greenland Ice Sheet (PROMICE) was initiated to observe and gain insight into the mass budget of Greenland ice masses. By means of in situ observations and remote sensing, PROMICE assesses how much mass is gained as snow accumulation on the surface versus how much is lost by iceberg calving and surface ablation (Ahlstrøm et al. 2008). A key element of PROMICE is a network of automatic weather stations (AWSs) designed to quantify components of the surface mass balance, including the energy exchanges contributing to surface ablation (Van As et al. 2013)

    Animal attacks - a red herring of child abuse?

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    Injuries sustained as a result of attacks by domestic animals, particularly canines, are occasionally encountered at the Red Cross Children’s Hospital Trauma Unit in Cape Town. Less than 1% of admissions are directly attributable to animal attacks. Animal attacks causing lethal injuries are very rare and should be assessed carefully. We recently dealt with two fatalities attributed to animal attacks

    Regional climate-model performance in Greenland firn derived from in situ observations

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    Recent record-warm summers in Greenland (Khan et al. 2015) have started affecting the higher regions of the ice sheet (i.e. the accumulation area), where increased melt has altered the properties of firn (i.e. multi-year snow). At high altitudes, meltwater percolates in the porous snow and firn, where it refreezes. The result is mass conservation, as the refrozen meltwater is essentially stored (Harper et al. 2012). However, in some regions increased meltwater refreezing in shallow firn has created thick ice layers. These ice layers act as a lid, and can inhibit meltwater percolation to greater depths, causing it to run off instead (Machguth et al. 2016). Meltwater at the surface also results in more absorbed sunlight, and hence increased melt in the accumulation area (Charalampidis et al. 2015). These relatively poorly understood processes are important for ice-sheet mass-budget projections
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