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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.
51

Damage Assessment of the 2022 Tongatapu Tsunami : With Remote Sensing / Skadebedömning av 2022 Tongatapu Tsunamin : Med Fjärranalys

Larsson, Milton January 2022 (has links)
The Island of Tongatapu, Tonga, was struck by a tsunami on January 15, 2022. Internet was cut off from the island, which made remote sensing a valuable tool for the assessment of damages. Through land cover classification, change vector analysis and log-ratio image differencing, damages caused by the tsunami were assessed remotely in this thesis. Damage assessment is a vital part of both assessing the need for humanitarian aid after a tsunami, but also lays the foundation for preventative measurements and reconstruction. The objective of this thesis was to assess damage in terms of square kilometers and create damage maps. It was also vital to assess the different methods and evaluate their accuracy. Results from this study could theoretically be combined with other damage assessments to evaluate different aspects of damage. It was also important to evaluate which methods would be good to use in a similar event. In this study Sentinel-1, Sentinel-2 and high-resolution Planet Imagery were used to conduct a damage assessment. Evaluating both moderate and high-resolution imagery in combination with SAR yielded plausible, but flawed results. Land cover was computed for moderate and high-resolution imagery using three types of classifiers. It was found that the Random Forest classifier outperforms both CART and Support Vector Machine classification for this study area.  Land cover composite image differencing for pre-and-post tsunami Sentinel-2 images achieved an accuracy of around 85%. Damage was estimated to be about 10.5 km^2. Land cover classification with high-resolution images gave higher accuracy. The total estimated damaged area was about 18 km^2. The high-resolution image classification was deemed to be the better method of urban damage assessment, with moderate-resolution imagery working well for regional damage assessment.  Change vector analysis provided plausible results when using Sentinel-2 with NDVI, NDMI, SAVI and BSI. NDVI was found to be the most comprehensive change indicator when compared to the other tested indices. The total estimated damage using all tested indices was roughly 7.6 km^2. Using the same method for Sentinel-1's VV and VH bands, the total damage was estimated to be 0.4 and 2.6 km^2 respectively. Log ratio for Sentinel-1 did not work well compared to change vector analysis. Issues with false positives occurred. Both log-ratios of VV and VH gave a similar total estimated damage of roughly 5.2 km^2.  Problems were caused by cloud cover and ash deposits. The analysis could have been improved by being consistent with the choice of dates for satellite images. Also, balancing classification samples and using high-resolution land cover classification on specific areas of interest indicated by regional methods. This would circumvent problems with ash, as reducing the study area would make more high-resolution imagery available.
52

Lågstadielärares upplevda utmaningar med klimatundervisning inom de naturorienterande ämnena / Primary School Teachers’ Experienced Challenges with Climate Education in Natural Science Education

Forss, Matilda, Friberg, Li January 2023 (has links)
Klimatförändringar är i dagens samhälle ett påtagligt problem och skolans uppdrag är att lära ut området för unga. Det komplexa ämnet kan orsaka utmaningar och känslor, specifikt klimatångest, som lärare tvingas hantera för att stödja elever att bli medvetna och uppmuntrade till att arbeta för hållbar utveckling. Däremot behandlas inte klimatförändringar i någon större utsträckning i det centrala innehållet i läroplanen för NO-ämnena i årskurs 1-3.  Syftet med studien är att undersöka lärares upplevda utmaningar med klimatundervisning inom NO-ämnena i de lägre årskurserna och hur dessa hanteras. Studien syftar även till att undersöka hur NO-lärare hanterar klimatångest i undervisningen.  Studien genomfördes med semistrukturerade intervjuer med fem NO-lärare för årskurs F- 3 och materialet analyserades genom tematisk analysmetod. Analysen utgår från teoretiska begrepp, exempelvis klimatångest och eco-anxiety, samt känslohanteringsstrategier för att diskutera resultatet.  Resultatet visar att de utmaningar NO-lärarna såg var nivåanpassning, media, lärarnas egna engagemang samt kunskaper och transparens. Engagemang var den mest uttalade positiva känslan lärarna upplevde hos både sig själva och eleverna. Negativa känslor som klimatångest och oro var synligt hos lärare och elever. Lärarna hanterade utmaningarna genom att börja klimatundervisningen tidigt och inte ignorera fenomenet. De arbetade även elevnära och lösningsfokuserat.  Utifrån resultatet blir det synligt att klimatångest skulle kunna ses som en stor utmaning med NO- och klimatundervisning på lågstadiet. Lärarnas erfarenheter av hantering av klimatångest som utmaning utgår mestadels från menings- och problemfokuserade strategier och i mindre grad emotionsfokuserade hanteringsstrategier.
53

Det sårbara hållbara samhället : En studie om elmarknadens förutsättningar utifrån klimat och väder i en Sydsvensk kontext / The vulnerable sustainable society : A study concerning the powermarket's situation in regards to climate and weather in a southern Swedish context

Tedestam, Joel January 2023 (has links)
Syfte Syftet är att utreda kopplingen mellan väder och elproduktion i ett begränsat sydsvensktområde; elområde 4. Metod Arbetet kommer att utföras med en kvantitativ och en kvalitativ metod. Den kvantitativametoden innefattar den största delen av den empiriska huvudundersökningen och utgörs avinsamlad data från SMHI och Nordpool. Det kvantitativa materialet kommer att redogöras föri diagramform vilket utgör grunden för den kvalitativa analysen. Begreppet hållbarhetkommer att figurera som en central punkt för arbetets utformning. Resultat Resultaten består av väder- och klimatdata från ett antal utvalda väderstationer i elområde 4vilka visar på hur olika väderförutsättningar skapar trender för elproduktion. Kustnäraområden har väderkontexter som lämpas bäst för placering av vindkraftverk. Områden iinlandet är mer problematiska och måste utvärderas individuellt för lämplighet förvindkraftsparker. Temperaturerna i elområde 4 visar på en regional sänkning av temperaturenunder slutet av november 2022. I resultaten finns även en betydande undersökning omelmarknadens förutsättningar i elområde 4, främst då med tanke på elproduktion och elprisersamt elhandel. Elproduktionen i elområde 4 är i huvudsak beroende av vindkraft ochsamtidigt finns det ett stort behov av elhandel med andra elområden. Slutsats Kopplingen mellan väder och elpriser är tydligast inom två kategorier, nämligen elproduktionoch elkonsumtion. Elproduktionen varierar kraftigt från dag till dag beroende påvindhastigheten, vilken i sin tur skapar förutsättningar för vindkraften som elområde 4 ärberoende av. Över tid har vindkraftverken en rimlig förmåga att producera el men från dag tilldag kan elproduktionen och därmed även elpriserna variera oerhört mycket. Elkonsumtionensyftar främst på behovet av uppvärmning vilket är onekligt sammankopplat med höjningaroch sänkningar i temperaturen. Det är temperaturförändringar som styr de störreförändringarna i elmarknadens balans mellan produktion och konsumtion. Vid mycket kallatemperaturer kan inte elproduktionen längre hålla jämna steg med konsumtionen ochelpriserna skjuter i höjden.
54

Possibilities of rewetting agricultural land for decreasing greenhouse gas emission and sustainable adaptation to flooding : -A case study from two sites in Sweden

Lamin, Noore Wazid January 2015 (has links)
The consequence of climate change will be more flooding in some areas and problems with sea-level rise. Drained wetlands and lakes that today are used for agriculture in the future may need to be rewetted because it might be unsustainable to continue to drain them. Rewetting these lands will have many positive effects like for instance decreased greenhouse gas emissions since these lands due to their high organic matter content are emitting a lot of CO2 and N2O. In this study two sites that could become candidates for rewetting have been studied and compared for their CO2 and N2O emissions. This was done by using a method for sampling gases both from a closed chamber and directly from soil. The emission rates were higher for Ramsjön compared to Vesan for both gases that could probably be an effect of season. A strong covariation between the two gases was shown for Ramsjön and the relationship was fairly strong for Vesan this indicates a common process for releasing the two gases. Rewetting these areas would probably have a high potential for saving greenhouse gas emissions and possibly also serve as flood adaptation areas with a high biodiversity and recreational value.
55

Beyond Conservation: Unlocking livelihoods, empowering communities : The case of Mamirauá

Leon Lavandera, Alejandra January 2023 (has links)
The spread of Community-based Natural Resources Management (CBNRM) programs can be attributed to the failure of top-down approaches and the development of more equitable governance strategies. A CBNRM approach seeks to fulfill dual objectives by balancing environmental conservation goals and local livelihood opportunities. This thesis analyzes how the implementation of CBNRM programs at Mamirauá Sustainable Development Reserve (MSDR) influences the available livelihood opportunities for local communities. Data was gathered through document analysis and online qualitative interviews and questionnaires with MSDR's staff, directly involved with these programs. The study found that trust, empowerment, and engagement are crucial for the effective implementation of these programs. By including local knowledge, promoting community participation and organization, providing continuous training, and having an ongoing evaluation and adaptation approach when managing resources, MSDR balances conservation goals with local development. Additionally, results indicate that the existing challenges are related to the efficacy of policy and legislative frameworks at the local and national levels, which complicates the work of implementing organizations. The findings suggest that a participatory approach to conservation can lead to positive outcomes, highlighting the importance of sustainable development within protected areas. These results have implications for future CBNRM projects and deepen our understanding of the intrinsic relationship between nature conservation and local livelihoods.
56

Dekomponeringsanalys av personbilstrafikens CO2-utsläpp i Sverige 1990–2015

Kalla, Christelle January 2019 (has links)
År 2045 ska Sverige uppnå territoriella nettonollutsläpp och till år 2030 ska utsläppen från transportsektorn ha minskat med 70 % jämfört med år 2010. Sveriges vägtrafik står för en tredjedel av de totala växthusgasutsläppen. För att uppnå klimatmålen bör de mest lämpade styrmedlen och åtgärderna prioriteras. En systematisk undersökning av de faktorer som påverkat utsläppsutvecklingen kan vägleda beslutsfattare att fördela resurserna där de gör mest nytta. Dekomponeringsanalys är en potentiell metod för detta syfte då flera olika faktorers effekter kan särskiljs och mätas. Fem additiva LMDI-I dekomponeringsanalyser genomfördes på utsläppsutvecklingen av fossilt CO2 inom personbilstrafiken mellan åren 1990–2015. De faktorer som undersöktes var befolkning, bil per capita, bränsleteknologier, motorstorlekar, trafikarbete per bil, emissioner och biobränsle. Data från emissionsmodellen HBEFA, Trafikverket och SCB användes i analyserna. Under hela perioden 1990–2015 minskade CO2-utsläppen och dekomponeringsanalyserna visade att alla de ingående faktorerna påverkat utvecklingen. Sett över hela tidsperioden 1990–2015 hade faktorerna påverkat utvecklingen mest i storleksordningen trafikarbete per bil (35 %), bränsleteknologier (15 %), befolkning (15 %), bil per capita (13 %), emissioner (11 %), biobränsle (7 %) samt motorstorlekar (5 %). Procenten anger andelen som faktorn utgjorde av effekternas absoluta summa. Trafikarbete per bil, emissioner, biobränsle och motorstorlekar minskade utsläppen. Bränsleteknologier, befolkning och bil per capita ökade utsläppen. Resultaten kan användas som en indikation för vilka faktorer som kan påverka den framtida utsläppsutvecklingen mest och för vilka åtgärder bör vidtas. Åtgärderförslag är incitament för att välja mer hållbara transportsätt, öka andelen av bilar med lägre utsläpp i fordonsflottan och använda mer biobränsle. / By year 2045 Sweden shall reach zero territorial net emissions and by year 2030 the emissions from the transport sector shall be reduced by 70% compared to year 2010. In Sweden the road traffic stands for a third of the total greenhouse gas emissions. In order to achieve the climate targets, the most suited policies and actions should be prioritized. A systematic investigation into the factors that affect the change in emissions can guide decision makers to distribute resources where they contribute the most. A decomposition analysis is a potential method for this purpose since the effect of different factors can be separated and measured. Five additive LMDI-I decomposition analyses were made on the change in fossil CO2 emission from passenger cars in Sweden between year 1990–2015. The factors that were investigated were: population, vehicle per capita, fuel technologies, engine sizes, distance travelled per vehicle, emissions and biofuel share. Data from the emissions model HBEFA, the Swedish Transport Administration and Statistics Sweden were used in the analyses. During the period of year 1990–2015 the CO2 emissions were reduced, and the decomposition analyses showed that all ingoing factors affected the change. Throughout the period the factors that contributed the most were in order of size: distance travelled per vehicle (35%), fuel technologies (15%), population (15%), car per capita (13%), emissions (11%), biofuel (7%) and engine size (5%). The percentage is the share of the factor’s effect of the absolute sum of all the different effects. Distance travelled per vehicle, emissions, bio fuels and engine size reduced the emissions. Fuel technologies, population and car per capita increased the emissions. The suggestions of actions are incentive for people to use more sustainable means for transportation, increase the share of cars with lower emissions in the fleet and use more biofuel.
57

Storm Frequency in the Northern Baltic Sea Region and its Association to the North Atlantic Oscillation

Arra, Venni January 2018 (has links)
Storms can be both destructive and valuable at the same time. They expose coastal areas to various risks but can also enhance the supply of wind energy and provide marine ecosystems with oxygen rich water. As the North Atlantic Oscillation (NAO) is known to have a significant impact on the wind climate in Europe, investigating its interconnection to storm frequency and intensity under global warming circumstances in the Northern Baltic Sea region was of interest in this study. Wind speed data series of annual storm counts were obtained from five meteorological stations along with PC-based NAO values over the period 1960-2017. The data series were analysed in Microsoft Excel and modelled using a Poisson regression or negative binomial regression model in SPSS Statistics. The results display an unsystematic spatial pattern both in the association to the NAO as well as in the overall storm frequency. However, storm (≥ 21 m s-1) frequency has generally been decreasing, whereas the proportion of severe storms (≥ 24 m s-1) has slightly been increasing, suggesting a tendency toward stronger but fewer storms. Even though only certain data series display statistically significant findings (p ≤ .05), a majority of the winter storms and severe winter storms display a positive association, indicating that a higher NAOI is related to a greater number of winter storms. The spatial and temporal variability in the obtained results can partially be explained by storm tracks and prevalent wind directions. Nevertheless, inhomogeneities do presumably affect the wind speed observations through internal and external influences and changes related to the meteorological stations. Future research should, therefore, also consider integrating other storm related parameters, such as direct air pressure measurements, wave heights and storm surges, as well as implement different data homogenization methods and techniques.
58

Assessing the impacts of climate change on runoff along a climatic gradient of Sweden using PERSiST / Utvärdering av klimatförändringars effekt på avrinningen längs en klimatgradient av Sverige med hjälp av PERSiST

Salmonsson, Tobias January 2013 (has links)
Climate change is a well-studied subject but large uncertainties still exist in future projections. These uncertainties are even larger on future runoff projections at catchment scales due to the differences in local landscape factors. Continuous assessments are therefore needed to improve our understanding and increase our preparedness for the future. One way forward is to assess the impact of climate change on runoff with the new hydrological model PERSiST. PERSiST was calibrated to four study catchments that spread out along a south-north climate gradient of Sweden. The model well simulated the stream discharges with Nash-Sutcliffe values ranging from 0.55 to 0.76. The model was then driven by downscaled and bias-corrected weather data (2061–2090) from an ensemble of 15 Regional Climate Models. The runoff projections showed that the impact of climate change on runoff would differ across the catchments. All catchments would see an increase in annual runoff with the greatest increase in the northernmost catchment. The northernmost catchment would also see a likely decline in spring flood, a shift in timing of the spring flood from May to April and an increase in winter runoff. As a result of an increase in winter runoff, there could be a loss of seasonality. In the more southern catchments the present-day runoff was more evenly distributed during the year and the projected loss of seasonality was not as pronounced. The conclusion was that the impact of climate change on runoff would increase northward, due to the higher response to climate change in the northernmost catchments. / Klimatförändringar är ett välstuderat ämne men stora osäkerheter kvarstår vad gäller framtida projektioner. Dessa osäkerheter är ännu större när det kommer till framtida projektioner av avrinning på grund av stora olikheter i lokala faktorer. Därför är fortsatta utvärderingar av nytta för att öka förståelsen och förbättra förberedelsen för framtiden. Ett steg i rätt riktning är att utvärdera klimatförändringars effekt på avrinning med hjälp av den nya hydrologiska modellen PERSiST. PERSiST kalibrerades för fyra olika avrinningsområden som var utspridda längs en syd-nord-gradient av Sverige. Den kalibrerade modellen simulerade det observerade flödet med Nash-Sutcliffe värden från 0,55 till 0,76. Modellen kördes sedan med nerskalad och bias-korrigerad väderdata (2061–2090) från en ensemble av 15 regionala klimatmodeller. Resultatet visade att klimatförändringars effekt på avrinning varierade mellan avrinningsområdena. Alla avrinningsområden påvisade en ökning i total årlig avrinning. Den största ökningen stod att finna i det nordligaste avrinningsområdet. Det nordligaste avrinningsområdet påvisade även en trolig minskning i vårflodsvolym, en skiftning av vårfloden från maj till april samt högre flöden vintertid. Som ett resultat av högre flöden vintertid uppstod en minskning av säsongsvariation. I de sydligare avrinningsområdena var dagens flöden jämnare fördelade över året, vilket gjorde att minskningen av säsongsvariation inte var lika stor. Slutsatsen var att klimatförändringarnas effekt på avrinning ökar norrut.
59

Possible Impact from Alaskan Forest Fires on Glaciers of St. Elias Mountains, Yukon Canada / Potentiell påverkan från Alaskas skogsbränder på S:t Eliasbergens glaciärer, Yukon Kanada

Hoang, Cham, Stangefelt, Moa January 2015 (has links)
How great potential effect does the Black carbon emitted from the boreal forest fire region of Alaska have on the retreating glaciers of the St. Elias Mountains? In this study climate and forest fire history data of Alaska was run in the HYSPLIT wind trajectory model to generate trajectories originated from large occurring fires in Alaska from 2005 to 2014. Results show a small percentage of trajectories passing the St. Elias Mountains and an expected pattern of a correlation between passing trajectories and density of amount forest fires. Interdisciplinary climate research is indicating an increase in global temperatures with consequences such as an upswing of forest fires in the Northern Hemisphere. Inner Alaska is fire prone due to a combination of prevailing droughts during the summer season and frequent lightning ignition as a result from homogeneous vegetation and topography. Downwind from Alaska’s forest fire region is the ice field of the St. Elias Mountains, these glaciers are one of the fastest retreating due to increasing global temperatures and possible deposition of soot from Alaskan forest fires. Forest fire emits black carbon, which when deposited on snow or ice surfaces will decrease the albedo and accelerate the melting rate. Previous studies on ice cores from the St. Elias have investigated traces of combustion products from biomass burning. This indicates a possible record of historic forest fires in ice cores. The small percentage of passing trajectories in this study suggests that most large forest fires in Alaska might not be registered in the St. Elias ice cores.
60

The Impact of Climate Changes On Hydrology and Water Resources In the Andean Páramos-Colombia

Cresso, Matilda January 2019 (has links)
Páramo ecosystems are unique alpine grasslands found at high altitudes (2000-5000 m a.s.l.) in the Andean mountain range. While they provide a wide range of important ecosystem services, such as organic carbon sinks, protect endemic species, provide agriculture services, act as recreation sites etc., their perhaps most important service is found in their ability to regulate water flows. The unique volcanic soil properties and endemic plant life that resides in these areas have an exceptional ability to capture, regulate and store water. Colombia has the world’s largest stretch of páramo areas, which supply almost the entire country with clean tap water without active filtration initiatives. Currently there are around seven million people living in Bogotá, the main capital. Northeast of the capital, in the Eastern Range of the Colombian Andes, the Chingaza National Park (CNP) is located. In this park, there are approximately 645 km² of páramo ecosystems, which supplies around 80 % of all the tap water used in Bogotá. However, with an expanding population growth and urbanisation, the demand for water is increasing rapidly. The long-lasting conflict within the country has prevented the exploitation of the economical goods belonging to the páramo ecosystems. Recent peace agreements have opened up for international trade, tourism and an expanding industry. However, the lack of regulations, which protect the páramo ecosystems, have now resulted in an increasing pressure of these systems. As such, sustainable adaptation plans are required across multiple stakeholder levels in order to prevent further deterioration of the páramos. Moreover, the anthropogenic climate changes are posing a threat to these fragile environments. An increasing temperature and changing rainfall patterns are expected to affect the hydroclimatic conditions, especially on high altitudes where these ecosystems are located. Nevertheless, the internal and external processes governing these ecosystems are highly complex and the knowledge gaps are many. One reason for this is that the remote and inaccessible locations results in generally scarcely distributed networks of monitoring stations. In this study, CNP was chosen due to the relatively well-monitored network of stations. Long-term temperature, precipitation and runoff data was analysed to identify the hydroclimatic conditions in the park. Regional downscaled precipitation, minimum and maximum temperature simulations under the Representative Concentration Pathways (RCP) 4.5 and 8.5, covering the period 2041-2065 were obtained from the WorldClim 1.4 database. Interpolated historical observations for the same parameters but during the period 1960-1990, covering CNP, were derived from the same database. These interpolated historical parameters were used for establishing upper and lower precipitation and temperature boundaries for where a páramo ecosystem can thrive during future RCP-scenarios. Historically, the hydroclimatic conditions in CNP has been characterised by a high input of water from precipitation, low evapotranspiration due to low temperatures and clouds presence, and a stable and abundant runoff. However, the results from this study suggest increasing temperature and precipitation boundaries during both RCP 4.5 and RCP 8.5 compared to historical interpolated data. Furthermore, there is a tendency towards prolonged and amplified seasons, with wetter wet season and drier dry seasons. When mapping suitable páramo environments under future RCP-scenarios, there is a tendency towards decreasing suitable páramo areas, especially during dry season. However, the findings in this report are merely based on temperature and precipitation parameters. Other forcing factors (ENSO, cloud cover, fog, occult precipitation, land use etc.) that also influence these environments and the ability to adapt to new hydroclimatic conditions, were not investigated. In order to prevent further loss of these environments and their associated ecosystem services, it is recommended to apply modern techniques, such as remote sensing in combination with traditional fieldwork, point samples and hydrological models in future studies.

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