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Visar resultat 16 - 20 av 72 avhandlingar som matchar ovanstående sökkriterier.

1. 16. Recent changes in land use and productivity in agro-pastoral Inner Mongolia, China

   Författare :Sara Brogaard; LUCSUS; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; geomorphology; Physical geography; China; Inner Mongolia; remote sensing; LUE model; primary production; GPP; yield variability; land degradation; farmers’ perception; productivity; Land use; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

   Sammanfattning : This study challenges the prevailing assumption that the expansion of cultivated land areas and increasing number of livestock in the agro-pastoral regions of northern China have aggravated the process of land degradation since the start of the rural reforms in 1978. Land-use and productivity trends in the Inner Mongolia Autonomous Region (IMAR), with special attention to the Keerqin steppe region, have been analysed. LÄS MER

3. 17. Function and dynamics of woody debris in boreal forest streams

   Författare :Niklas Dahlström; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Boreal forest; CPOM; CWD; forest management; geomorphology; LWD; riparian forest; retention; residence time; streams; Sweden; woody debris; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. LÄS MER

4. 18. Relationships between Atmospheric Circulation and Wind Erosion in Southern Sweden and Australia

   Författare :Marie Ekström; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi; Physical geography; geomorphology; Geologi; fysisk geografi; physical geography; Geology; sea level pressure; atmospheric circulation; erosivity; wind erosion; wind climatology; Scania; Australia;

   Sammanfattning : Wind erosion is a serious threat to soil resources as it causes depletion of the fine fractions that may result in a less fertile soil. Wind erosion encompasses several processes of which many are related to climate variables. To date, there is little work performed on how wind erosion relates to climate and climate change. LÄS MER

5. 19. Swash Processes and Dune Erosion: Emphasis on Vessel-Generated Waves

   Författare :Li Erikson; Avdelningen för Teknisk vattenresurslära; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; marklära; kartografi; klimatologi; Civil engineering; hydraulic engineering; geomorfologi; Fysisk geografi; climatology; cartography; pedology; geomorphology; Naturvetenskap; Physical geography; Natural science; swash; erosion; vessel-generated waves; dunes; offshore technology; soil mechanics; Väg- och vattenbyggnadsteknik;

   Sammanfattning : In navigable waterways, owing to the relatively short fetches for wind wave generation, the free waves generated by moving vessels often produce the dominant wave action with respect to erosion of the shore. In response to the fairly recent introduction of high-speed ferries, combined with a planned expansion within the passenger- and car-carrying ship market, the need to model and predict coastline changes as a result of exposure to vessel-generated waves has become a topic of increased research. LÄS MER

7. 20. 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; 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