Search for dissertations about: "GPP"

Showing result 1 - 5 of 28 swedish dissertations containing the word GPP.

2. 1. Land degradation and mitigation in northern China. Evaluated from the biological production

   Author : Micael Runnström; Institutionen för naturgeografi och ekosystemvetenskap; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; marklära; geomorfologi; Fysisk geografi; climatology; kartografi; klimatologi; cartography; pedology; desertification; China; GPP; Mu Us; LUE-model; overgrazing; Physical geography; geomorphology;

   Abstract : Land degradation is commonly perceived to be severe in many parts of semi arid China. The transition towards market economy since the 1978 reforms, have set marginal dry lands under added pressure in the form of increased livestock numbers and expanding cultivation on erosive soils. READ MORE

4. 2. Mapping Primary Production for the West African Sahel with Satellite Data

   Author : Jonathan Seaquist; Institutionen för naturgeografi och ekosystemvetenskap; []
   Keywords : 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;

   Abstract : 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. READ MORE

5. 3. Climate change impacts on production and dynamics of fish populations

   Author : Per Hedström; Pär Byström; Jan Karlsson; Peter Eklöv; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Temperature; terrestrial dissolved organic carbon; light extinction; GPP; recruitment; winter mortality; metabolism; cohort competition; fish production; fish biomass;

   Abstract : Ongoing climate change is predicted to increase water temperatures and export of terrestrial dissolved matter (TDOM) to aquatic ecosystems influencing ecosystem productivity, food web dynamics and production of top consumers. Ecosystem productivity is mainly determined by the rates of primary production (GPP) in turn controlled by nutrients, light availability and temperature, while temperature alone affect vital rates like consumption and metabolic rates and maintenance requirements of consumers. READ MORE

6. 4. Vegetation Observation in the Big Data Era : Sentinel-2 data for mapping the seasonality of land vegetation

   Author : Zhanzhang Cai; Institutionen för naturgeografi och ekosystemvetenskap; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Sentinel-2; Times-series analysis; Phenology; GPP;

   Abstract : Using satellite remote sensing data for observing vegetation seasonality is an important approach to estimate phenology and carbon uptake of land vegetation. The successful launch of Sentinel-2B in 2017 initiated full operation of the Sentinel-2 twin satellites, and they now provide 10 - 60 m spatial resolution satellite data at 5 days temporal resolution worldwide, releasing approximately 3. READ MORE

7. 5. Recent changes in land use and productivity in agro-pastoral Inner Mongolia, China

   Author : Sara Brogaard; LUCSUS; []
   Keywords : 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;

   Abstract : 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. READ MORE