Currently there is no extended study that explicitly focuses on themagnitude, frequency and timing of glacial calving resulting from externalforces. Past studies have identified the size and timing of calving events butthe links between them and the external factors that cause them are stillmissing. Here I present a method to identify the size, time and frequency ofcalving events on the Rink Glacier in Greenland. Using time lapse imagesspaced 30 minutes apart of the calving front, coupled with weather and tidedata, I plan on identifying the main driving force for calving. Results showthat atmospheric pressure and temperature have no positive correlation withcalving magnitude or size. Tidal influences and sea surface temperatureappear to have the strongest influence on the frequency of calving. As seasurface temperatures rapidly decrease though the study period, calvingfrequency also reduces. Strong calving correlations for the entire studyperiod were difficult to identify for tidal influences, as images could only betaken during the sunlit periods of the day. As this study was conductedduring autumn when atmospheric temperatures remained below 0°C, theavailability of melt water for crevasse creation and basal lubrication was notpresent. Therefore it is suggested that future studies on glacial stabilityshould use external forces to measure ice loss over the entire calving season.

There is increasing recognition that the hydrology of the Greenland Ice Sheet plays an important role in the dynamics and therefore mass balance of the ice sheet. Understanding the hydrology of the ice sheet and being able to predict its future behaviour is therefore a key aspect of glaciological research. To date, the ice sheet’s hydrology has tended to be inferred from the analysis of surface velocity measurements, or modelled in a theoretical, idealised way. This study focuses on the development of a high spatial (100 m) and temporal (1 hour) resolution, physically based, time-dependent hydrological model which is applied to the ~2,300 km2 Paakitsoq region, West Greenland, and is driven, calibrated, and evaluated using measured data. The model consists of three components. First, net runoff is calculated across the ice sheet from a distributed, surface energy- balance melt model coupled to a subsurface model, which calculates changes in temperature, density and water content in the snow, firn and upper-ice layers, and hence refreezing. The model is calibrated by adjusting key parameter values to minimize the error between modelled output and surface height and albedo measurements from the three Greenland Climate Network (GC-Net) stations, JAR 1, JAR 2 and Swiss Camp. Model performance is evaluated in two ways by comparing: i) modelled snow and ice distribution with that derived from Landsat-7 ETM+ satellite imagery using Normalised Difference Snow Index (NDSI) classification and supervised image thresholding; and ii) modelled albedo with that retrieved from the Moderate- resolution Imaging Spectroradiometer (MODIS) sensor MOD10A1 product. Second, a surface routing / lake filling model takes the time-series of calculated net runoff over the ice sheet and calculates flow paths and water velocities over the snow / ice covered surface, routing the water into ‘open’ moulins or into topographic depressions which can fill to form supraglacial lakes. This model component is calibrated against field measurements of a filling lake in the study area made during June 2011. Supraglacial lakes are able to drain by a simulated hydrofracture mechanism if they reach a critical volume. Once water is at the ice / bed interface, discharge and hydraulic head within subglacial drainage pathways are modelled using the third model component. This consists of an adaptation of a component (EXTRAN) of the U.S. Environmental Protection Agency Storm Water Management Model (SWMM), modified to allow for enlargement and closure of ice-walled conduits. The model is used to identify how the subglacial hydrological system evolves in space and time in response to varying surface water inputs due to melt and lake drainage events, driven ultimately by climate data. A key output from the model is the spatially and temporally varying water pressures which are of interest in helping to explain patterns of surface velocity and uplift found by others, and will ultimately be of interest for driving ice dynamics models.

Loess from west Greenland was studied to evaluate Holocene paleoclimate in the Arctic region. Deposits of loess are formed over long time scales through deposition of fine aeolian sediment and they exist in several places in the world. The main aeolian dust source in the study area is glaciofluvial material derived from the Greenland Ice Sheet (GrIS). Studying and understanding paleoclimate can help to make better predictions about the future in this sensitive region. Apart from sea level rise, melting of the GrIS also leads to an increase of aeolian dust as it gets released from the ice, which influences atmospheric and metrological phenomenon as well as the ice sheet’s albedo. This creates negative feedback mechanisms through increasing melting rates of glaciers and warming of the Arctic. Loess samples from two sites in the Kangerlussuaq area were analyzed and the mineral composition was measured with X-Ray Florescence Spectroscopy (XRF). With the measured mineral content, weathering indices were calculated to identify rates of weathering during the Holocene. Increased weathering intensities indicate warmer and more humid climate. The deposits in Greenland are relatively thin. Radiocarbon dating of the sediment suggests that the oldest parts of the profiles are about 4000 cal. yr B.P. (calibrated years before present). Arctic loess has not been studied very extensively. Weathering indices and ratios developed for classical loess, that had not been tested on Arctic loess, was used. The results were plotted by depth and age to visually identify changes over time. By considering the geology, climate and local conditions of the study area, some weathering indices seemed to be suitable, generating matching trends between the two sites. Compared with results from previous studies, the results also seemed credible. / Löss från västra Grönland studerades för att utvärdera holocent paleoklimat i Arktis. Lössjordar bildas över långa tidsskalor genom avsättning av fint vindburet sediment och de finns på flera platser i världen. Den huvudsakliga källan till det vindburna sedimentet i studieområdet är glaciofluvialt material härstammande från Grönlandsisen (GrIS). Att studera och förstå paleoklimat kan underlätta skapandet av bättre prognoser om framtiden i denna känsliga region. Bortsett från höjning av de globala havsnivåerna leder smältningen av GrIS också till en ökning av vindburet sediment då det frigörs från isen, vilket påverkar atmosfäriska och metrologiska fenomen samt isens albedo. Detta skapar negativa återkopplingsmekanismer genom ökande smälthastighet av glaciärer och uppvärmning av Arktis. Lössprover från två ställen i Kangerlussuaq-området analyserades och mineralsammansättningen mättes med röntgenstrålningsspektroskopi (XRF). Med det uppmätta mineralinnehållet beräknades vittringssindex för att identifiera vittringshastigheter under Holocen. Ökad vittringsintesitet indikerar varmare och fuktigare klimat. Avlagringarna på Grönland är relativt tunna. Kol-14-datering av sedimentet antyder att de äldsta delarna är cirka 4000 cal. yr B.P. (kalibrerade år före nutid). Arktisk löss är relativt ostuderad. Vittringsindex som har utvecklats för klassisk löss i tempererade regioner, och tidigare inte testats på arktisk löss, användes. Resultaten ritades i grafer efter djup och ålder för att visuellt identifiera förändringar över tid. Genom att ta hänsyn till geologin, klimatet och lokala förhållanden i studieområdet, verkade några av vittringsindexen ge trovärdiga resultat då matchande trender mellan bägge profiler kunde utläsas. I jämförelse med resultat från tidigare studier verkade resultaten också trovärdiga.

The Inuit people in Greenland are internationally recognized as indigenous. They, therefore, have been granted protective measures, such as self-government rights in 2009. However, some scholars have started to question whether protective measures are still a necessity because of their increased autonomy rights. To contest this questioning, this paper examines the contemporary political discourse in Greenland regarding the Inuit people’s emphasis on their cultural heritage, ongoing identity issues, and aspirations of independence, in the light of Will Kymlicka’s liberal theory of multiculturalism. The paper concludes that the Inuit people in Greenland, to a large extent, apply to Kymlicka’s theory regarding his criteria of national minorities and the importance of belonging to a societal culture. However, the study also finds that his theory is limited in protecting potential sub-cultures and lacks nuances about secessionist thoughts among indigenous groups. The results underline the importance of continuingly protect indigenous peoples in Greenland and suggests considering additional measures to other minorities on the island.

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Spaceborne microwave sensors are powerful tools for monitoring the impacts of global climate change on the Greenland ice sheet. This dissertation focuses on refining methods for applying microwave data in Greenland studies by using new simple theoretical and empirical models to investigate (1) azimuth anisotropies in the data, (2) the microwave signature of the snow surface, (3) detection of snow melt, and (4) classification of snow melt. The results are applicable for identifying geophysical properties of the snow surface and monitoring changes on the ice sheet in relation to melt duration/extent, accumulation, and wind patterns. Azimuth dependence of the normalized radar cross-section (sigma-0) over the Greenland ice sheet is modeled with a simple surface scattering model. The model assumes that azimuth anisotropy in 1-100 meter scale surface roughness is the primary mechanism driving the azimuth modulation. This model is inverted to estimate snow surface properties using sigma-0 measurements from the C-band European Remote Sensing Advanced Microwave Instrument (ERS) in scatterometer mode. The largest roughness estimates occur in the lower portions of the dry snow zone. Estimates of the preferential direction in surface roughness are highly correlated with katabatic wind fields over Greenland. A new observation model is introduced that uses a limited number of parameters to characterize the snow surface based on the dependence of radar backscatter on incidence angle, azimuth angle, spatial gradient, and temporal rate of change. The individual model parameters are discussed in depth with examples using data from the NASA Scatterometer (NSCAT) and from the ERS. The model may be applied for increased accuracy in scatterometer, SAR, and wide-angle SAR studies. Examples illustrating the use of the model are included with one application focusing on analysis of inter-annual change and another focusing on increased sensitivity in studies of intra-annual change. Six different melt detection method/sensor combinations are compared using data for the summer of 2000. The sensors include the Special Spectral Microwave Imager (SSM/I), SeaWinds on QuikSCAT (QSCAT), and ERS. A new method of melt detection is introduced that is based on a simple physical model relating the moisture content and depth of a layer of wet surface snow to a single channel melt detection threshold. The model can be applied to both active and passive sensors. Model-based melt estimates from different sensors are highly correlated and do not exhibit the unnatural phenomenon observed with previous methods. Trends in SSM/I channel ratios are used to differentiate subsurface and surface melt. For ablation estimation, this separation is important due to expected differences in the ablation rate for the two melt types. Evidences of the daily melt refreeze cycle are observed in the diurnal variation of the different brightness temperature channel ratios. The polarization ratio increases during periods of surface melt while the frequency ratio remains relatively constant. The frequency ratio increases during periods of expected subsurface melt. Similar trends are observed in brightness temperature measurements from in situ data collected by other investigators.

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