Sökning: "Vegetation index"

Visar resultat 1 - 5 av 40 avhandlingar innehållade orden Vegetation index.

  1. 1. Analyzing Vegetation Trends with Sensor Data from Earth Observation Satellites

    Författare :Sadegh Jamali; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Change detection; Satellite sensor data; Time series analysis; Vegetation dynamics; Vegetation index;

    Sammanfattning : Abstract This thesis aims to advance the analysis of nonlinear trends in time series of vegetation data from Earth observation satellite sensors. This is accomplished by developing fast, efficient methods suitable for large volumes of data. LÄS MER

  3. 2. Circumpolar impacts of herbivores on Arctic tundra vegetation

    Författare :Elin Lindén; Johan Olofsson; Maja K. Sundqvist; Mariska te Beest; Elisabeth S. Bakker; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; herbivores; grazing; Arctic; circumpolar; tundra; vegetation; plant defence; secondary metabolites; shrub birch; exclosures; vegetation; species diversity; biology; biologi;

    Sammanfattning : Arctic tundra vegetation provides many ecological services that have implications for the global climate. However, the tundra biome is currently changing in response to increasing temperatures. Herbivores may mitigate some of these responses to warming through their impact on Arctic vegetation. LÄS MER

  4. 3. Changes in plant community diversity and management effects in semi-natural meadows in southern Sweden

    Författare :Anna-Carin Linusson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plant ecology; Vegetation; Species diversity; Management intensity; Community diversity; Ordination; Växtekologi;

    Sammanfattning : The objectives of this thesis were to: 1) survey the vegetation in semi-natural meadows in south-central Sweden, 2) discern meadow vegetation changes in eight semi-permanent plots between studies performed in the 1960s and in 1990, 3) experimentally investigate the effects of variations in management intensity in one dry and one mesic meadow, 4) experimentally investigate the effects of different management practices or absence of management on species dynamics in meadow vegetation. 1. LÄS MER

  5. 4. Satellite remote sensing of primary production in semi-arid Africa

    Författare :Martin Sjöström; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; remote sensing; primary production; vegetation index; savanna; grassland;

    Sammanfattning : With the challenges Africa faces with respect to the predicted warming due to climate change, the continents role in the global carbon cycle has been increasingly recognized. Earth observing satellites have played a significant role in the study of vegetation, particularly in Africa where climate stations are sparse. LÄS MER

  7. 5. A GIS-based landscape analysis of dissolved organic carbon in boreal headwater streams

    Författare :Jan-Olov Andersson; Lars Nyberg; Hjalmar Laudon; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boreal forests; wetlands; vegetation types; headwater streams; catchment hydrology; streamwater chemistry; DOC; GIS; terrain analysis; DEM; slope; wetness index; TWI; Freshwater ecology; Limnisk ekologi; Biology; Biologi;

    Sammanfattning : In boreal catchments, stream water chemistry is influenced and controlled by several landscape factors. The influence of spatially distributed variables is in turn dependent on the hydrological scale. LÄS MER