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Showing result 11 - 15 of 21 essays matching the above criteria.

  1. 11. Spatial Variation of THg and MeHg Stream Concentrations and Its Relation to TOC

    University essay from Uppsala universitet/Institutionen för geovetenskaper

    Author : Maria Tranvik; [2017]
    Keywords : Mercury; organic matter; catchment characteristics; GIS; deforestation; Kvicksilver; organiskt material; avrinningsområdesfaktorer; GIS; skogsavverkning;

    Abstract : Mercury (Hg) which originates from global emissions to the atmosphere can deposit far away from the source. There is often a weak correlation between Hg deposition and concentrations in runoff, therefore catchment specific parameters might be of importance in controlling the amount of Hg ending up in watercourses and fish. READ MORE

  3. 12. Hydrological modeling enhancement using GIS : An improved topographic wetness index for wetland detection

    University essay from Stockholms universitet/Institutionen för naturgeografi

    Author : Patricia Rull; [2016]
    Keywords : Blue spots; digital dams; culverts; hydrologically enforced DEM; topographic wetness index; TWI; soil-topographic wetness index; STI; wetland detection;

    Abstract : Hydrological modeling, like runoff modelling for flood prevention, is based on digital elevation models (DEMs). The fact that the DEMs do not represent existing road culverts can lead to considerable hydrological misinterpretations. READ MORE

  4. 13. Can the introduction of the topographic indices in LPJ-GUESS improve the spatial representation of environmental variables?

    University essay from Lunds universitet/Institutionen för naturgeografi och ekosystemvetenskap

    Author : Alejandra Narváez Vallejo; [2016]
    Keywords : smooth topography; drainage area; slope; topographic wetness index; LPJ-GUESS; GIS; physical geography and ecosystem analysis; geography; geographic information systems; leaf area index; spatial patterns; MODIS LAI.; Earth and Environmental Sciences;

    Abstract : Ecosystem modelling is an always evolving science trying to catch the complexity of the nature and its principles to model environmental responses in a realistic way. Over and over, models try to introduce more variables and interactions to achieve better representations of phenomena of interest like the responses of the ecosystem to a fast changing world (climate change, land use change). READ MORE

  5. 14. The Origin of Streams : Stream cartography in Swiss pre alpine headwater

    University essay from Uppsala universitet/Institutionen för geovetenskaper

    Author : Oskar Sjöberg; [2016]
    Keywords : Temporary stream; Stream cartography; Drainage density; Hydrological connection; Topographic wetness index; Upslope accumulated area; Stream head; Headwater catchment;

    Abstract : Temporary streams have received undeservedly little scientific attention and as a result their role in hydrological, biogeochemical and ecological processes is not yet fully understood. The ultimate goal of the research was to gain a better understanding of the temporary stream network and the processes that control it and determine how the active and connected stream length change with catchment wetness conditions to find simple methods to map seasonal and event-based changes in temporary flowing stream networks. READ MORE

  6. 15. Topografins inverkan på markvattenhalten i ett jordbruksdominerat avrinningsområde

    University essay from SLU/Dept. of Soil and Environment

    Author : Olof Haraldsson; [2015]
    Keywords : topografi; jordbrukslandskap; markvattenhalt; dränering; avrinningsområde;

    Abstract : Topography is an important parameter for catchment hydrology, since it is a driver for water flow. Moreover, topography serves as a basis for hydrological models, e.g. ‘Top-model’, which is based on a topographical wetness index (TWI). READ MORE