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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

The future of flooding insurances : A qualitative review of how insurances regarding flood damage might change in the future of the insurance industry in Sweden

Nyström, David January 2023 (has links)
Insurance companies are grappling with the rising frequency and severity of extreme weather-related flooding events, which currently pose the highest financial burden both in total and per individual case. The existing insurance model isn't economically sustainable if such events continue to increase. To assess future needs and challenges in flooding insurances, research on changing weather patterns and interviews with employees at major firms were conducted. The research indicates that climate change has and will further worsen extreme rain events in Sweden, leading to more frequent and intense flooding events. Interviews revealed that firms are aware of impending changes in the insurance industry due to climate change but lack proactive measures to address them. Responsibility is fragmented, and communication between stakeholders is suboptimal. To address these challenges, I look at recent research regarding flood risk assessment and if these are applicable for the insurance industry in Sweden to ensure future profitability.
222

Undervisning utanför klassrummets fyra väggar : En kvalitativ empirisk studie gällande den låga inkluderingen av fältstudier i skolämnet geografi.

Karlsson, Julia January 2024 (has links)
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.
223

Using NDVI Time-Series to Examine Post-fire Vegetation Recovery in California

Wu, Viktor January 2022 (has links)
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.
224

GIS, tracer test and water balance based hydrological analysis in Tarfala, Northern Sweden

Koivisto, Elias January 2022 (has links)
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.
225

Spatial Variability in Winter Balance on Storglaciären Modelled With a Coupled Terrain Based Approach / Modellering av rumsligvariation av vintermassbalansen på Storglaciären med hjälp av en koppladterrängbaserad metod

Terleth, Yoram January 2021 (has links)
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.
226

Shallow near-surface lapse rates and their connection to glacier meteorology on Storglaciären and Rabots glaciär, Northern Sweden

Taveirne, Moon January 2022 (has links)
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.
227

Seasonal permafrost subsidence monitoring in Tavvavuoma (Sweden) and Chersky (Russia) using Sentinel-1 data and the SBAS stacking technique

Rehn, Ida January 2022 (has links)
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.
228

Hållbar utveckling i ett förändrat klimat : utmaningar och framsteg inom klimatanpassning

Awiti, Maximilian January 2023 (has links)
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.
229

How important are water sources to pastoralist movement in times of climate change? : A modelling approach.

Mischke, Max Louis January 2023 (has links)
Livestock grazing is an important part for the livelihood of a large part of the world’s population. While in some areas of the world water accessibility is often taken for granted, in arid regions this can be a limited resource. The central Asian country of Mongolia is one of the countries that sees excessive livestock grazing in an arid region. Nomadic pastoralism is widespread to ensure access to fresh water sources as well as pastures. These movement patterns are under ongoing research, but so far, the impact of water accessibility on these movement patterns has not been investigated. Specifically in the Great Gobi B Strictly Protected Area, pastoralists rely on water obtained from a variety of sources like lakes, rivers, and wells. I analysed camp usage and the availability of water for pastoralists to uncover current movement patterns and how these are influenced by water. I want to gain insight on how the distance to the closest water source influences camp usage and how this changes with seasonality and the size of the herd. For this I conducted Kruskal-Wallis and two-sided Pearson tests respectively. A potential overlap between wildlife and livestock was investigated since this might be a potential conflict and further leading to the spread of diseases. Furthermore, I modelled precipitation and temperature until the year 2050 to spot a potential redistribution of water in an already arid region. There was no correlation found between the seasons nor herd size and the distance to the closest and second closest water source. In my analysis, the overlap between wildlife and livestock was found only to a minor extend. Precipitation and temperature in the region were found to change only to a marginal degree from 2023 to 2050. Due to this, I identified the most important water sources and camps based on the analysisof the current data.
230

Investigating the response of terrestrial evapotranspiration to droughts in Africa : A combined remote sensing and modeling approach

Foo, Yang January 2023 (has links)
Climate change is posing a significant threat to terrestrial ecosystems worldwide, in part due to the more frequent occurrence of extreme climatic events such as droughts. While the importance of drought impacts on vegetation has been widely recognized, the time-dependent characteristics of drought-induced response remain insufficiently understood. In this study, we examine the sensitivity of terrestrial evapotranspiration (ET) to water availability in African biomes using a suite of satellite and geospatial data. By correlating a multi-scalar drought index with monthly ET anomalies between 1981 and 2016, the spatiotemporal effects of drought are evaluated and compared against simulations from a coupled vegetation-climate model. The coupling between water availability and ET is found to be largely dependent on aridity conditions and the evapotranspiration regime (energy- vs. soil moisture-limited). We also observed the dominant role of root zone storage capacity in mediating ET response among rainforests and savannas, whereas shrubs and grasslands tend to exhibit much more complex soil-plant interactions. Comparing between model simulations and observations, discrepancies in the magnitude and timing of ET response were evident. Our findings highlight the need for an explicit consideration of plant-available water to improve the representation of hydroclimatic processes in Earth system models.

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