Sökning: "Institutionen för naturgeografi och ekosystemvetenskap"

Visar resultat 11 - 15 av 85 avhandlingar innehållade orden Institutionen för naturgeografi och ekosystemvetenskap.

1. 11. Dissolved organic carbon in tropical watersheds : Linking field observation and eco-hydrological modelling

   Författare :Fabien Rizinjirabake; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dissolved organic carbon DOC ; Rwanda; Land use land cover variability; Climate variability and change; Rukarara River Watershed; eco-hydrological modelling; field observation;

   Sammanfattning : Dissolved organic carbon (DOC) is a general description of the organic material dissolved in water. DOC is an important source of energy, carbon, and nutrient transfers from terrestrial to aquatic ecosystems. The export of DOC into aquatic ecosystems may contribute to the carbon balance of terrestrial ecosystems and to water degradation. LÄS MER

3. 12. Tree phenology modelling in the boreal and temperate climate zones : Timing of spring and autumn events

   Författare :Cecilia Olsson; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Plant phenology in the boreal and temperate climate zones is synchronised with seasonal changes in temperature and photoperiod. For deciduous trees, timing of budburst and leaf colouring define the growing season length and express adaptations to trade-offs in growth and risks. LÄS MER

4. 13. Model development for estimating carbon dioxide exchange in Nordic forests and peatlands with MODIS time series data

   Författare :Per Schubert; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : The ongoing increase in atmospheric greenhouse gas concentrations causes an increase in the global mean air temperature. One important moderator of the atmospheric carbon dioxide (CO2) concentration is the gas exchange between the atmosphere and the biosphere; photosynthesis extracts and respiration releases CO2, resulting in a net exchange. LÄS MER

5. 14. The role of biogeophysical feedbacks and their impacts in the arctic and boreal climate system

   Författare :Wenxin Zhang; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic and boreal vegetation change; Biogeophysical feedbacks; Albedo; Latent heat; Carbon budget; Representative concentration pathways; Eearth system model; LPJ-GUESS; RCA; Sea ice;

   Sammanfattning : The physical environment in the northern high latitudes including the Arctic cryosphere has undergone dramatic changes due to anthropogenic greenhouse gas warming, which since pre-industrial times has been twice or more the rate of global mean warming. Global climate models predict that this accelerated warming will continue for at least the next few decades. LÄS MER

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

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

   Sammanfattning : 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. LÄS MER