Glaciers as Indicators of Climatic Change - Background and Tools for Modelling

Glaciers may be used as indicators of climatic change. This paper presents data from six glaciers with records of glacier length greater than 200 years. All show a strong retreat since 1850. The paper discusses past work to model these glaciers based on climatological time series from nearby station. Studies performed until now have not produced good results and have only partially described the retreats of the past 100 years. A new, two-step modelling approach is presented here. The first component relates climate conditions to glacier mass balance followed by a second which calculates ice flow as a response to imposed mass balance. The mass balance approach uses an energy balance on the glacier surface, explicitly accounting for turbulent fluxes in the atmospheric boundary layer above the glacier surface and for the changes in albedo in the modelling of radiation. Meteorological data needed to run the mass balance module are temperature and humidity, cloudiness, and precipitation. A one-dimensional flow model based on equations of the continuity and motion is used to compute the dynamics of a glacier along the centerline down the surface slope. It takes into account varying lateral geometry, sliding and deformation of the glacier and changes in ice thickness. The coupled, two-component model system is solved using an explicit scheme for time integration. Various numerical techniques to improve computational efficiency are discussed. Preliminary results of this approach have been promising and will be discussed by a follow-up paper

A quasi-analytical ice-sheet model for climate studies

A simple quasi-analytical model is developed to study the response of ice-sheets to climate change. The model is axisymmetrical and rests on a bed with a constant slope. The mechanics are highly parameterised. The climatic conditions are represented by the altitude of the runoff line. Above the runoff line the accumulation rate is constant (but may depend on, for instance, the ice-sheet size), below the runoff line the balance gradient is constant. The ice-sheet may extend into the sea and can respond to changes in sea level. At the grounding line the ice velocity is assumed to be proportional to the water depth. For this set-up an explicit expression for the total mass budget of the ice-sheet is derived. To illustrate the properties and possibilities of the model, equilibrium states are analysed and the response to periodic forcing is studied as well. The coupling of mass balance and surface elevation of the ice-sheet leads to nonlinear behaviour and branching of the equilibrium solutions. The qualitative behaviour of the system is that of the cusp catastrophe. Nonlinear effects are more pronounced when the slope of the bed is smaller. A case is discussed in which two ice-sheets are coupled by making the altitude of the runoff line dependent on the total area of the two ice-sheets. On two continents, having a slightly different glaciation threshold, periodic forcing of the altitude of the runoff line is imposed. It is shown that in such a situation variations on a long time scale (two to three times the period of the forcing) are introduced. Finally the model is forced by the GISP <font face='Symbol'>d</font>¹⁸O record for the last 120 000 years. For an appropriate choice of parameters the model simulates well the waxing and waning of the Laurentide, Fennoscandian and Barentsz ice-sheets

The Franki Committee (1976 Report) and Statutory Licensing

Contains fulltext : 140337.pdf (publisher's version ) (Closed access)We focus in this study on sets of inter-organizational relationships (IORs) by applying a configurational approach that includes both the diversity and the intensity of knowledge transfer IORs. We use a latent class cluster analysis to empirically explore the kinds of IORs configurations. We then use antecedents derived from the IOR literature to explain firm membership in those configurations. Our tests allow us to identify four configurations ranging from isolated innovators to innovating firms embedded in diverse and deep sets of IORs. We show that internal knowledge use by firms, and the types of innovative activities in which they engage, are strong predictors of firm membership in different configurations.19 p

Canons in the classroom: An exploration of teachers' selection of works for musicological examination in New South Wales.

This study provides a detailed view of current practice in relation to the New South Wales Board of Studies Music 2 Syllabus Mandatory Topic, ‘Music of the last 25 years (Australian focus)’. It closely examines various interpretations of this topic, and motivations behind these interpretations, through the voices of those involved in its implementation: an educational administrator, music educationalists, teachers and representatives from education-oriented arts organisations. Through interviews with these participants, this multi-case study examines patterns and influences behind the selection of works for the musicology component of the Mandatory Topic. Conducted across metropolitan and regional areas, the research investigates whether there is equitable access to resources. The study evaluates the complex factors and current practices in the selection of musicological works for study. By bringing to light the current unofficial canon shaped by teachers and others within NSW schools, this thesis proposes strategies for the teaching of musicology in ways that more accurately reflect contemporary educational thinking that is sound, progressive and inclusive

An explanation for the dark region in the western melt zone of the Greenland ice sheet

The western part of the Greenland ice sheet contains a region that is darker than the surrounding ice. This feature has been analysed with the help of MODIS images. The dark region appears every year during the summer season and can always be found at the same location, which makes meltwater unlikely as the only source for the low albedos. Spectral information indicates that the ice in this region contains more debris than the ice closer to the margin. ASTER images reveal a wavy pattern in the darker ice. Based on these findings we conclude that ice, containing dust from older periods, is presently outcropping near the margin, leading to albedos lower than observed for the remaining ablation area. Therefore it can be concluded that the accumulation of meltwater is a result rather than a cause of the darkening

Sectoral patterns of interactive learning : an empirical exploration using an extended resource based model

This paper pursues the development of a theoretical framework that explains interactive learning between innovating firms and external actors in the knowledge infrastructure and the production chain. The research question is: what kinds of factors explain interactive learning of innovating firms with external actors? In our theoretical framework we augment the resource-based perspective predominant in network theory with an activity based account and a structural account of interactive learning. We contend basically: that higher technological dynamics induce innovative activities with a higher complexity. More complex innovative activities increase the probability of internal resource deficits/shortages in the innovating firms. The higher the resource deficits/shortages and the lower the alignment of innovative activities the more likely the search for complementary resources externally, which increases the likeliness of external relationships. In order to test the generality of our theoretical claims we analyse our models within four sectors with different technological dynamics as distinguished by Pavitt. Furthermore we estimate four models within each sector predicting: 1) the level of interactive learning of innovating firms with the public knowledge infrastructure (difficult to access, demands high internal competences to utilise scientific knowledge), 2) the level of interactive learning of innovating firms with the production chain (easy to access), 3) the level of interactive learning of innovating firms with their users (here the innovating firms are the producers), 4) the level of interactive learning of innovating firms with their suppliers (here the innovating firms are the users), 5) the level of interactive learning with competitors. These analyses allow for a comparison between interactive learning with different external actors and give deeper insights into the differentiated interaction patterns governing innovation. Our fmdings show that patterns of interactive learning between sectors differ. Some are more resource based and others are more affected by the complexity of innovative activities. Particularly the interactive learning with the knowledge infrastructure differs from that with actors in the production chain

A fifty year record of winter glacier melt events in southern Chile, 38°–42°S

Little is known about the frequency and potential mass balance impact of winter glacier melt events. In this study, daily atmospheric temperature soundings from the Puerto Montt radiosonde (41.43°S) are used to reconstruct winter melting events at the glacier equilibrium line altitude in the 38°–42°S region of southern Chile, between 1960 and 2010. The representativeness of the radiosonde temperatures to near-surface glacier temperatures is demonstrated using meteorological records from close to the equilibrium line on two glaciers in the region over five winters. Using a degree-day model we estimate an average of 0.28 m of melt and 21 melt days in the 15 June–15 September period each year, with high inter-annual variability. The majority of melt events are associated with midlatitude migratory high pressure systems crossing Chile and northwesterly flows, that force adiabatic compression and warm advection, respectively. There are no trends in the frequency or magnitude of melt events over the period of record, but the annual frequency of winter melt days shows a significant, although rather weak and probably non-linear, relationship to late winter and early spring values of a multivariate El Niño Southern Oscillation Index (MEI)