Sökning: "Leaf area index LAI"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Leaf area index LAI.

  1. 1. Leaf Area Index of Scandinavian Forests Methods Using in situ and Remotely Sensed Data

    Författare :Helena Eriksson; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Geologi; fysisk geografi; Physical geography; geomorphology; Geology; physical geography; leaf aggregation; specific leaf area SLA .; Växtekologi; Plant ecology; Leaf area index LAI ; canopy reflectance models; spectral vegetation indices; remote sensing; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

    Sammanfattning : This thesis deals with methods of obtaining the leaf area index (LAI) from remotely sensed satellite data. Initially, in situ estimation methods were investigated, since the accuracy of the remotely sensed estimates is dependent on the quality of these estimates. LÄS MER

  2. 2. Evolution of Plants : a mathematical perspective

    Författare :Magnus Lindh; Åke Brännström; Jacob Johansson; Mats G Larson; Lennart Persson; Claus Rüffler; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Evolution; plants; mathematics; optimization; optimal control; adaptive dynamics; flowering; seasons; tree crown; drought; taproot; trade-off; strategy; trait; ESS; NPP; LAI; Red Queen; Mathematics; matematik;

    Sammanfattning : The Earth harbors around 300 000 plant species. The rich and complex environment provided by plants is considered a key factor for the extraordinary diversity of the terrestrial fauna by, for example, providing food and shelter. LÄS MER

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

    Författare :Martin Sjöström; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 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

  4. 4. Remote sensing phenology at European northern latitudes - From ground spectral towers to satellites

    Författare :Hongxiao Jin; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Remote sensing; climate sensitivity.; calibration; ground spectral tower; Plant phenology index PPI ; northern latitude;

    Sammanfattning : Plant phenology exerts major influences on carbon, water, and energy exchanges between atmosphere and ecosystems, provides feedbacks to climate, and affects ecosystem functioning and services. Great efforts have been spent in studying plant phenology over the past decades, but there are still large uncertainties and disputations in phenology estimation, trends, and its climate sensitivities. LÄS MER

  5. 5. Remote Sensing of Carbon Balance across Scandinavian Forests

    Författare :Pontus Olofsson; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Forests; Natural science; Naturvetenskap; Carbon balance; Remote sensing;

    Sammanfattning : A methodology for estimating the carbon balance across Scandinavian forests using remote sensing is presented. By estimating the gross primary production (GPP) and the ecosystem respiration (ER), and thereby, the net ecosystem exchange (NEE), using parameters that are routinely retrieved from satellite, it is possible to implement an operational model for obtaining large scale NEE. LÄS MER