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Showing result 1 - 5 of 13 swedish dissertations matching the above criteria.

  2. 1. Mapping Primary Production for the West African Sahel with Satellite Data

    Author : Jonathan Seaquist; Institutionen för naturgeografi och ekosystemvetenskap; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physical geography; Sahel; CENTURY; Monte Carlo; GPP; transpiration; LUE; CLAVR; PAR; compositing; MVC; geostatistics; noise; NDVI; NOAA AVHRR; geomorphology; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

    Abstract : A light Use Efficiency (LUE) model is developed that allows the mapping of total growing season Gross Primary Production (GPP) for the West African Sahel, using the Normalized Difference Vegetation Index (NDVI) together with other data. Image quality may be poor in monthly NDVI maximum value composites as shown by an improved geostatistical noise estimation technique. READ MORE

  4. 2. Towards Climate Based Early Warning and Response Systems for Malaria

    Author : Maquins Odhiambo Sewe; Joacim Rocklöv; Clas Ahlm; Yesim Tozan; Madeleine Thomson; Umeå universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Malaria; Mosquito; Lead time; Early Warnings; Forecasts; Economic Evaluation; Rainfall; KEMRI CDC HDSS; Kenya; Temperature; LST; NDVI; Climate; HDSS; GAM; GAMBOOST; DLNM; Remote Sensing; Net Benefit; Cost-Effectiveness; Boosting Regression; Weather; Public Health; Infectious Diseases; folkhälsa; Public health; Epidemiology; epidemiologi;

    Abstract : Background: Great strides have been made in combating malaria, however, the indicators in sub Saharan Africa still do not show promise for elimination in the near future as malaria infections still result in high morbidity and mortality among children. The abundance of the malaria-transmitting mosquito vectors in these regions are driven by climate suitability. READ MORE

  5. 3. Bush Encroachment and the Role of Browse in Cattle Production : An ecological perspective from a bush encroached grazing system, Olifants Drift, Kgatleng District, Southeast Botswana

    Author : Nkobi Moleele; Norman Owen-Smith; Stockholms universitet; []
    Keywords : savannas; bush encroachment; carrying capacity; browse; biomass; range degradation; colour infrared photographs; Landsat Thematic Mapper; mid infrared bands; tannins; toxins; aromatic substances; Dicrostachys cinerea; Grewia flava; NDVI; Olifants Drift; Botswana; naturgeografi; Physical Geography;

    Abstract : The increase in density and cover of woody plant species is coincident with the introduction of cattle in southern Africa, and it is a wide spread phenomenon in the savannas of the world. The causes are little understood, but can only be speculated to be either anthropogenic or natural or a combination of both. READ MORE

  6. 4. Land-atmosphere exchange of carbon in a high-Arctic wet tundra ecosystem

    Author : Torbern Tagesson; BECC: Biodiversity and Ecosystem services in a Changing Climate; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; carbon; methane; carbon dioxide; climate change; Arctic; NDVI; NDWI; micrometeorology; remote sensing; chamber; tundra;

    Abstract : Arctic ecosystems play a key role in the terrestrial carbon (C) cycle, but spa-tially explicit data on the C exchange is scarce in these remote areas. The global warming is especially dominant in the Arctic, and these areas are vul-nerable to climate change. READ MORE

  7. 5. AVHRR NDVI for monitoring and mapping of vegetation and drought in East African environments

    Author : Lars Eklundh; Institutionen för naturgeografi och ekosystemvetenskap; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geologi; fysisk geografi; physical geography; Geology; phenology; seasonality; Fourier series; geostatistics; signal-to-noise ratio;

    Abstract : In this thesis, an assessment is made of the performance of the Normalized Difference Vegetation Index (NDVI) derived from coarse resolution data from the NOAA AVHRR sensor, with particular reference to mapping and monitoring of drought and vegetation in East African vegetation and climatic conditions. Methods for analysing time series of satellite data are investigated. READ MORE