Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 67 for “"eddy covariance"”.
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Adoption of footprint methods for the quality control of eddy-covariance measurements
… combined a method for quality assessment of eddy-covariance measurements with an analytic footprint model. Their software package provided micrometeorologists a practical tool for determining the average flux contributions from the land use type intended to observe at a specific site, or to …
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Data-led methods for the analysis and interpretation of eddy covariance observations
The terrestrial biosphere impacts considerably on the global carbon cycle. In particular, ecosystems contribute to set off anthropogenic induced fossil fuel emissions and hence decelerate the rise of the atmospheric CO₂ concentration. However, the future net sink strength of an ecosystem will …
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Characterization of Urban Air Pollutant Emissions by Eddy Covariance using a Mobile Flux Laboratory
… equipped to measure pollutant fluxes by eddy covariance. The first campaign, conducted in Norfolk, Virginia, represented the first time fluxes of nitrogen oxides (NO<sub>x</sub>) were measured by eddy covariance in an urban environment. Fluxes agreed to within 10% of estimates in the …
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Eddy-covariance measurements as a tool for ecological and hydrological studies on the Tibetan Plateau
… by measurements of turbulent fluxes with the eddy-covariance (EC) method. This includes flux measurements over the most common two vegetation types on the TP, Kobresia pygmaea pasture and alpine steppe. In particular these in situ measurements were used to investigate differences in the fluxes …
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Forest respiration from eddy covariance and chamber measurements under high turbulence and a bark beetle epidemic
Eddy covariance (EC) enables continuous estimates of carbon, water, and energy fluxes, and a global network of >500 sites (www.fluxnet.ornl.gov) has resulted in major advances in understanding ecosystem-scale biogeochemical cycling. However, long-term sums of net ecosystem exchange, photosynthesis …
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Quality Assurance for Eddy Covariance Measurements of Turbulent Fluxes and its Influence on the Energy Balance Closure Problem
The eddy covariance method enables direct measurements of turbulent fluxes at the earth’s surface. Such measurements are required to study the surface energy balance and the exchange of gaseous air constituents. Due to improvements in the construction of adequate sensors and the progress in …
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A joint analysis of gross primary production and evapotranspiration of Australia using eddy covariance, remote sensing and land surface modelling approaches
… (ET) across Australian biomes in combination of eddy covariance, remote sensing and land surface model (LSM) methods, taking advantage of their respective applicability on different space and time scales. To do this, I (1) used the wavelet method to decompose eddy covariance observed half-hourly …
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Aircraft-based measurements for the identification and quantification of sources and sinks in the carbon cycle
… specific to operators and basins. Finally, eddy-covariance O<sub>2</sub> and heat fluxes were measured over three east-coast forests at sites close to and far from surface eddy-covariance towers. Tower data is often used in models to represent a larger heterogeneous region. Aircraft and …
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Site-specific modelling of turbulent fluxes on the Tibetan Plateau
… flux data of high quality for validation. Eddy-covariance measurements are qualified for this task, but these are scarce on the Tibetan Plateau, incomplete due to quality filtering and potentially biased due to the well-known closure gap of the observed energy balance as well as small-scale …
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Investigation of covariability between energy fluxes and CO2 exchange over a semi-arid savanna (Kruger National Park) by Eddie Covariance Technique
… fluxes and NEE at Kruger National Park using the eddy covariance technique, the dissertation seeks to deepen our understanding of the mechanisms driving carbon exchange in semi-arid savannas and provide insights into the impact of environmental factors on ecosystem processes. The eddy covariance …
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Heat transfer, evaporation and carbon dioxide transfer in soil
… (ET) were measured using stem flow gauges and an eddy covariance system in the corn field. The evapotranspiration estimated from the sum of heat pulse evaporation and stem flow transpiration (E+T), eddy covariance ET, and potential evapotranspiration, ET0, estimated from the Penman-Monteith …
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Carbon fluxes of an extensive meadow and attempts for flux partitioning
… Therefore, micrometeorological methods (Eddy-Covariance – EC, Relaxed Eddy Accumulation – REA), chamber measurements and isotopic methods are applied. First, the investigated area, an extensively managed grassland, was defined as a net carbon sink (–91 g C m–2 a–1) in 2010. Spring …
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Modeling the exchange of energy and matter within and above a spruce forest with the higher-order closure model ACASA
… data base for this purpose, particularly eddy-covariance and sap flux measurements at several heights within the canopy. Thorough model tests were a main focus of this study and led to an improvement of the investigated model. This included both the exploration of the sensitivity and …
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An analysis of the surface moisture fluxes in the Argentinian Cordoba region using the 2018-2019 RELAMPAGO field campaign data
… data using 15 stations, seven of which have Eddy Covariance flux measurements, to measure moisture-energy and momentum fluxes. Given the type of measurements and the high spatial density of the towers in a single agricultural region, the data offers an unprecedented opportunity to investigate …
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Cross-frontal exchange at the US Northeast shelfbreak
… and external forcing. In this thesis, I quantify eddy-driven exchange across the US Northeast shelfbreak front and its impact on the coastal ocean, starting on seasonal timescales and moving toward individual synoptic events. For this task, I take advantage of unprecedented multi-year observations …
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Canopy structural and meteorological influences on CO2 exchange for MODIS product validation in a boreal jack pine chronosequence
… a combination of CO2 measurements made by eddy covariance (EC), field measurements, remote sensing data, and ecosystem models. The integration of these is problematic because of a mis-match in scale between measurement techniques. Despite the importance of regenerating forests on the global …
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Cross-Frontal Exchange at the US Northeast Shelfbreak
… and external forcing. In this thesis, I quantify eddy-driven exchange across the US Northeast shelfbreak front and its impact on the coastal ocean, starting on seasonal timescales and moving toward individual synoptic events. For this task, I take advantage of unprecedented multi-year observations …
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Application of a Mobile Flux Lab for the Atmospheric Measurement of Emissions (FLAME)
… applies a proven, science-based method known as eddy covariance for the direct quantification of anthropogenic emissions to the atmosphere. The mobile flux lab is a tool with novel, multifaceted abilities to assess air quality and improve the fidelity of emission inventories. Measurements of air …
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The application of the surface energy balance system model to estimate evapotranspiration in South Africa
… (MODIS) satellite data and validated with eddy covariance data measured in a large apple orchard (11 ha), in the Piketberg area of the Western Cape. Due to the relative infancy of research in this field in South Africa, SEBS is an attractive model choice as it is available as open-source …
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Evaluating the influence of establishing pine forests and switchgrass fields on local and global climate
… influence local to global climate. Here I use eddy-covariance data to investigate how a transition from a perennial bioenergy crop (switchgrass) to a planted pine plantation alters the local surface temperature, global carbon dioxide concentrations, and global energy balance. First, I found …
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