Temperate mixed forests are complex ecosystems composed of multiple vegetation types with very different physiological characteristics which are distributed over the landscape. This dissertation investigates the influence of these mixed plant landscapes on eddy-covariance flux data, and in particular, uses an ecohydrological model to study the influence of climate variability and insect infestation on a mixed forest at the Harvard Forest Long Term Ecological Research site in Massachusetts. There are significant seasonal and interannual variabilities in the extent and the orientation of the footprints of a flux tower (EMS-tower) as the Harvard Forest. The Gross Primary Productivity (GPP) flux was found to be largely dependent on the vegetation density during the green-up and senescence periods, but not during the mature period. Half of the interannual anomalies in the mature period GPP flux can be explained by the variation in the proportion of coniferous evergreen needleleaf forest (ENF) in the footprint. Every 1% decrease of ENF resulted in the increase of the GPP flux by 20 gC m-2. The spatially-distributed process-based Regional Hydro-Ecological Simulation System (RHESSys) model was implemented in two headwater catchments at the Harvard Forest to simulate water and carbon cycles from 1992 to 2008. Results were evaluated using field measurements such as streamflow and the GPP and evapotranspiration (ET) fluxes at two flux towers. The simulated annual GPP flux of the deciduous forest showed strong and significant long-term increases, six times higher than the GPP flux of the coniferous forest, while the increase in ET flux of both forests was small yet significant. The Harvard Forest was infested by Hemlock Woolly Adelgid (HWA) between 2004 and 2008, and although there has not yet been a significant increase in the total annual mortality, the small stature stands have started to die off by 5.7%. The HWA infestation has already resulted in an increased streamflow in the catchment dominated by hemlock stands (44% in area). In 2014, the increased annual streamflow was estimated as 81 mm using the RHESSys model with an embedded representation of the HWA-induced loss of water conductivity (calibrated using the Hemlock tower ET flux).

Since far back in time, field studies have had a clear role in geography history. Likewise do field studies have a place in the current Swedish curriculum where students can encounter the teaching method in their knowledge development. However, statistics have shown that nearly 70% of participating primary school teachers have not used field studies in geography teaching during their previous school year. The aim of the study is to investigate the underlying factors why the inclusion of field studies in geography teaching is deficient. A qualitative survey in the form of interviews was conducted with 6 competent geography teachers. The results showed that a good teacher's attitude towards field studies is decisive for the outcome of field studies, as well as that teachers face limitations in aspects such as curriculum understanding, place, time, lack of conditions in terms of education, assurance of safety, students benefit and group dynamics.

Over the past couple of decades, fires have experienced changes on a global scale. These changing fire regimes point to an alarming direction where fire-dependent ecosystems are experiencing a decline in burned area, while fire-independent ecosystems are experiencing an increase. As a result, land cover change is seen in both types of ecosystems where the native plant communities run the risk of disappearing, and recovery becomes increasingly important. One of the areas experiencing a notable increase in fires is California, US. Here, both observed and projected changes indicate increasing frequency of fires, fire size and fire severity. In this study, post-fire recovery for 5 land cover types in California is compared using Normalized Difference Vegetation Index (NDVI) time-series. Two metrics are used for post-fire recovery, where a metric that describes short-term recovery is found most appropriate for a comparison between land cover types. It is found that the land cover type “Trees” has the longest recovery, followed by “Herbaceous/Shrubs”. Faster recovery times are found in the late fire season compared to the early fire season, indicating an influence of precipitation on post-fire vegetation recovery. Similarly, faster recovery times are found in a semi-arid climate zone compared to the Mediterranean climate zones. This indicates the potential influence of species composition on post-fire vegetation recovery. Results particularly show differences in post-fire recovery between land cover types, but also between fire seasons and climate zones. To examine these details in further detail, fire severity, meteorological data, and a more detailed classification for vegetation types could be implemented as factors determining post-fire recovery.

Current climate change poses a threat to the Arctic due to increasing temperatures, which cause the permafrost and glaciers to melt and thaw. This thesis focused on analyzing water balances in Tarfala catchment between 2000 and 2020 and using GIS as a support for tracer test results measured in Tarfala in 2021. The results suggest that high resolution DEM data are more useful compared to low resolution DEM when it comes to understanding local hydrology. In addition, analyses regarding tracer test data suggest that permafrost can act both as a hinder and water flow pathway changer in Tarfala. Water balance calculations show that the area is highly affected by snow, permafrost and climate change and may come to change towards wetter and snow and permafrost free conditions due to climate change. / Den pågående klimatförändringen har en markant effekt på det arktiska ekosystemet på grund av de stigande temperaturerna vilket orsakar permafrosttining. Denna uppsats fokuserade på att analysera vattenbalanser mellan 2000 och 2020 i Tarfalas avrinningsområde samt diskutera hur spårämnesförsök och GIS kan användas för att analysera de lokala förhållandena i områden med permafrost. Resultaten tyder på att högupplöst DEM data kan användas som stöd för spårämnestester som påverkas starkt av jordartssammansättningen och permafrost i Tarfalas avrinningsområde. Resultaten tyder också på att vattenbalans i Tarfala påverkas och har påverkats av flera olika faktorer såsom permafrost, snö och klimatförändringar och kan komma att förändras i framtiden till mer våta samt snö- och permafrostfria förhållanden.

Although most processes governing the surface mass balance on mountain glaciers are well understood, the causes and extent of spatial variability in accumulation remain poorly constrained. In the present study, the EBFM distributed mass balance model is newly coupled to terrain based modelling routines estimating mass redistribution by snowdrift, preferential deposition, and avalanching (ST-EBFM) in order to model winter balance on Storglaciären, Sweden. STEBFM improves the spatial accuracy of winter balance simulations and proves to be a versatile and computationally inexpensive model. Accumulation on Storglaciären is primarily driven by direct precipitation, which seems locally increased due to small scale orographic effects. Wind driven snow transport leads to significant deposition in the accumulation zone and slight erosion in the ablation zone. The pattern is generally consistent from year to year. Avalanching is the smallest contributor to winter balance, but cannot be neglected. The physical complexity of avalanches and high year to year variability render simulations of the process somewhat uncertain, but observations seem to confirm the large impact that the process can have on the glacier at very localised scales. The role of mass transporting processes in maintaining the current mass equilibrium on Storglaciären highlights the necessity to understand the links between climatic predictors and accumulation in order to accurately assess climate sensitivity.

No description available.

Glacier melt is strongly impacted by climate and meteorology. Temperature lapse rates are used to model glacier melt, and the accuracy of the spatial distribution of modelled melt can be impacted by the lapse rate used in modelling. Additionally, the observed spatial distribution of melt is highly temporally variable. Whether this variability is caused by lapse rate is unknown. Storglaciären and Rabots glaciär in Northern Sweden were equipped with temperature measurement stations at both low and high glacier elevations over the 2014 ablation season. From these measurements, surface lapse rates 0.1 m above the glacier surface, and near-­surface lapse rates 2 m above the surface, were calculated for the two glaciers. The lapse rates were then compared to meteorological variables measured in the middle of the glaciers’ elevation range. In addition, a comparison was made with ablation data collected via ablation stakes throughout the melt season. On both Storglaciären and Rabots glaciär, the surface lapse rate is −0.28 °C (100m)−1 averaged over the ablation season. The season ­average near­-surface lapse rate is also the same for both glaciers, at −0.37 °C (100m)−1. The lapse rate values are shallow in comparison to non-­glaciated mountain areas. The meteorological variables of wind speed and precipitation affect surface lapse rate on short timescales. Long-­term patterns in surface lapse rate are influenced by incoming radiation, humidity and precipitation. In addition, topographic shading and albedo impact the incoming short­-wave radiation, causing diurnal and seasonal fluctuations in surface lapse rate. A cumulative approach to lapse rate using a positive degree day gradient reflects the pattern of ablation gradients measured through the ablation season. However, a lack of data means no robust conclusions can be drawn from this comparison. Many melt modelling studies use steeper lapse rates in ablation and mass balance modelling than observed over Storglaciären and Rabots glaciär. This can lead to underestimation of ablation at high glacier elevations. Measurements of local lapse rates recorded over glacier surfaces are necessary in order to produce more accurate ablation modelling results.

Permafrost deformation is expected to increase due to climatic perturbations such as amplified air and soil temperatures, resulting in permafrost thawing and subsequent subsidence. Palsas and peat plateaus are uplifted ice-rich peat mounds that experience permafrost subsidence. This is due to the uppermost layer of permafrost, known as the Active Layer (AL), that seasonally thaws and freezes. Interferometric Synthetic Aperture Radar (InSAR) is an interferometric stacking technique successfully applied over permafrost regions when monitoring ground subsidence. The Small Baseline Subset (SBAS) technique is based on interferograms produced by stacking Synthetic Aperture Radar (SAR) acquisitions with small normal baselines. In this study, seasonal Sentinel-1 SAR C-band data obtained during June, July, August and September (JJAS) was used to generate seasonal Line of Sight (LoS) deformation time series of palsas and peat plateaus in Tavvavuoma (Sweden) by using the SBAS technique. Chersky (Russia) has documented permafrost subsidence and was used as a reference site. Findings include that seasonal stacks with short normal baselines generated more robust results than inter-annual stacks with longer normal baselines and temporal data gaps. No instances of pronounced subsidence were reported during JJAS. Nevertheless, minor subsidence during the early season and negative development trends were identified in the Tavvavuoma 2020 andChersky 2020-2021 stacks, respectively. Increased subsidence during the mid-and late thaw season was detected. The SBAS technique performed better and resulted in less temporal and seasonal decorrelation in areas above the tree line (Tavvavuoma) compared to the lowlands in the forest-tundra (Chersky). The challenge lies in whether surface subsidence of palsas and peat plateaus in sporadic permafrost regions experience irreversible long-term changes or seasonally cyclic changes in the permafrost ground regime. Future studies are recommended to implement annual intervals, including winter images over Tavvavuoma.

No abstract provided. / Thesis / Bachelor of Arts (BA) / Introduction: The study attempts to explain the geographical conditions in Westminster Township. Emphasis is placed on the relationship existing between the township and the city of London, the large metropolitan centre adjacent to it. The problem is attacked from a functional point of view. The physical geography of the township is described. However, since historical forces are recognized in any study of settlement, one chapter is devoted to historical geography. The following chapters are devoted to communications and land use patterns, both rural and urban. The thesis is changing interrelationship, between the city and the township. It shows clearly that the city does not terminate at its political boundary, but encroaches upon the adjacent rural township. The result is a change in the character of the township in the shape of an "Urban Fringe" specialized agriculture and new super imposition of communications.

Denna studie utreder hur hållbara utvecklingsinitiativ inom klimatanpassning inramas i kommunala visioner från de två svenska kommunerna Kristianstad och Trelleborg. Båda städerna befinner sig i prekära geografiska lägen och är speciellt i riskzonen för de stigande havsnivåerna. Klimateffekterna är redan här och havsnivåerna förväntas att bli allt värre i samband med den stigande temperaturen. Kommunerna har ett viktigt ansvar i klimatanpassningen. Kommunerna ansvarar för den fysiska planeringen och därav ansvar för mark- och vattenregleringen. Syftet med studien är att undersöka huruvida Kristianstad och Trelleborg lyckas sammanfläta klimatanpassningsplaneringen med alla tre hållbarhetsdimensioner (ekologiska, sociala och ekonomiska). Studien avser att utvärdera hur dessa dimensioner värderas i kommunernas kommunala dokument, genom en kvantitativ innehållsanalys. Tidigare forskningen tyder på att det är svårt att synkronisera de tre hållbarhetsdimensionerna och istället står de i vägen för varandra och tenderar att favorisera den ekonomiska hållbarheten. Resultaten från Kristianstad efterliknande den tidigare forskningen, där de ekonomiska värdena överskuggade de andra hållbarhetsaspekterna. De var snarlikt mellan de ekologiska och ekonomiska, men framförallt var det den sociala hållbarheten som fick väldigt lite uppmärksamhet. Trelleborg fick dock andra resultat. Det var fortfarande en väldigt svag balans mellan dimensionerna, dock var värderingen av dimensionerna annorlunda. Den sociala, men framförallt den ekologiska, värderades högre än den ekonomiska.