Sökning: "Institutionen för naturgeografi och ekosystemvetenskap"

Visar resultat 21 - 25 av 85 avhandlingar innehållade orden Institutionen för naturgeografi och ekosystemvetenskap.

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

    Författare :Jonathan Seaquist; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

  3. 22. Linking distributed hydrological processes with ecosystem vegetation dynamics and carbon cycling: Modelling studies in a subarctic catchment of northern Sweden

    Författare :Jing Tang; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Carbon cycling; Water cycling; Hydrological modelling; Ecosystem modelling; Subarctic ecosystems; Climate change;

    Sammanfattning : The Arctic and Subarctic regions are of particular importance to the global climate change and are now experiencing a climate warming that is higher than the global average. Around 50% of the global soil carbon is stored in high latitude soils, especially in permafrost and peatland soils. LÄS MER

  4. 23. The Earth : climate and anthropogenic interactions in a long time perspective

    Författare :Jörgen Olofsson; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; anthropogenic; climate change; land use; biodiversity; carbon; dynamic global vegetation model; Holocene; pre-industrial; pollen; bison;

    Sammanfattning : The Earth is a highly complex and dynamic system. Life has shaped the entire planet and evolved in response to living conditions. Ecosystems are heavily affected by climate. Rapidly changing conditions imply considerable stress on several species and ecosystems, as well as to the most dominant species on the planet. LÄS MER

  5. 24. Potential impact of climate change on European agriculture: a case study of potato and Colorado potato beetle

    Författare :Bakhtiyor Pulatov; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Colorado potato beetle; climate change; day length; degree day model; frost damage; distribution; temperature; potato; regional climate model; synchrony;

    Sammanfattning : European agriculture is facing the challenge of managing the impact of climate change on food security. Agriculture in a northern temperate climate is likely to benefit from higher temperature and longer growing season while, in the south, crop productivity is likely to decline. LÄS MER

  7. 25. Tundra meets atmosphere : Seasonal dynamics of trace gas exchange in the High Arctic

    Författare :Norbert Pirk; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic; tundra; methane; carbon dioxide;

    Sammanfattning : Arctic environments have experienced strong warming in recent decades, which is affecting the carbon cycle of tundra ecosystems.Degrading permafrost, diminishing snow cover, and changing hydrology are examples of ongoing processes that affect the land-atmosphere interactions and seasonal ecosystem dynamics. LÄS MER