1,720,962 research outputs found
Multiyear eddy covariance and meteorological dataset from agroforestry and open cropland or grassland in northern Germany
No full textDataset corresponding to the project SIGNAL (Sustainable intensification of agriculture through agroforestry), subproject TP1.2, entitled "CO2, H2O and energy exchange". Christian Markwitz collected and processed the data corresponding to the 1st phase, 2016-2018. Justus van Ramshorst collected and processed the data corresponding to the 2nd phase, 2019-2021. José Ángel Callejas-Rodelas collected and processed the data corresponding to the 3rd phase, 2022-2024. Lukas Siebicke and Alexander Knohl wrote the project proposals and contributed to data analysis and harmonization. Project funded by the German Ministry of Education and Research (BMBF), project BonaRes, module A (first phase: SIGNAL 031A562A, second phase: SIGNAL 031B0510A, third phase: SIGNAL 031B1063A)
Genetic Programming in Hydrology: Using genetic programming in conceptual modelling
No full textThis report introduces the use of Genetic Programming (GP) into hydrology by describing the results of GP using conceptual hydrological models as physical representation. First the possibilities of GP are tested on synthetic data, which results in a shortlist of good working objective functions and insight in the most important GP settings. The test on real data in the Belgium Ardennes showed that GP using the objective functions KG10, MM and Shafii performed better. Nevertheless all three models performed not well on simulating the low flows and high peaks. Furthermore GP using KG10 and MM both results in simple serial models which perform well overall, but bad on quick response runoff. Shafii resulted in parallel models which show quick response flow, however GP it is not able to capture the fast responses correctly (yet). GP has the potential to improve the understanding in the behaviour of catchments, however it still needs the human mind to observe, compare and analyse the modelling results. The main consideration with GP is to look for a balance between: model search space, objective function, randomness and (computational) time. The challenge is how to lead GP in an efficient way without removing the possibility of finding unknown patterns.Additional thesisWater Managemen
Wind speed measurements using distributed fiber optics: a wind tunnel study
No full textNear-surface wind speed is typically only measured by point observations. The so-called Actively Heated Fiber-Optic (AHFO) technique, however, has the potential to provide high-resolution distributed observations, allowing for better understanding of different processes. However, before it can be widely used, its performance needs to be tested in a range of settings. Therefore, in this work, experimental results on this novel observational wind-probing technique are presented. We utilized a controlled wind-tunnel setup to assess both the accuracy and the precision of AHFO as well as its potential for outdoor atmospheric operation. The technique allows for wind speed characterization with a spatial resolution of 0.3 m on a 1 s time scale. The flow in the wind tunnel is varied in a controlled manner, such that the mean wind, ranges between 1 and 17 m/s. Comparison of the AHFO measurements with observations from a sonic anemometer shows a high overall correlation, ranging from 0.94-0.99. Also, both precision and accuracy are greater than 95 %. As such, it is concluded that the AHFO has potential to be employed as an outdoor observational technique in addition to existing techniques. In particular, it allows for characterization of spatial varying fields of mean wind in complex terrain, such as in canopy flows or in sloping terrain. In the future the technique could be combined with regular Distributed Temperature Sensing (DTS) for turbulent heat flux estimation in micrometeorological/hydrological applications
Groundwater recharge in Myanmar - Estimations in the Chindwin catchment by base flow separation and SWAT
No full textFirst estimations for the groundwater recharge in the Chindwin basin in Myanmar are presented in this report. This estimations are based on base flow separation and a SWAT model. Multiple base flow separation methods are applied and these are compared with the base flow produced by the SWAT model. This first estimations show a range of 248-670 mm average groundwater recharge per year, which is roughly 11-30% of the average annual rain in the catchment. The upper limit, produced by SWAT, seems to be too high, as the total flow is overestimated due to a rate of evaporation which is too low compared with remote sensing based evaporation. In the Chindwin it appeared that it is rather difficult to separate the base flow due to the highly sensitive alpha parameter, which determines the response behaviour of the base flow, also there seem to be multiple groundwater components. This makes it hard to perform base flow separation, but also increases the difficulty of calibrating the SWAT model, especially the base flow component. However the SWAT model shows a clear spatial groundwater recharge pattern even though it needs further optimization. Optimizing a (hydraulic) model can be cumbersome and especially in a developing environment as Myanmar it is also interesting to look at other possibilities/models, like Water Accounting +, which are more flexible to adapt to changes as new dams or increase in groundwater irrigation.InternshipWater Managemen
A multiyear eddy covariance and meteorological dataset from five pairs of agroforestry systems with open cropland or grassland in Northern Germany
No full textAbstract. Agroforestry systems are considered suitable nature-based solutions to mitigate climate change. Long-term measurements of CO2 flux densities, evapotranspiration and sensible heat flux densities are, however, largely still missing. Here we present a unique eddy covariance and meteorological dataset from a total of ten stations paired over agroforestry and open cropland or grassland agricultural sites located in Northern Germany. The data were harmonized to create a consistent dataset which includes gap-filled time series of meteorological and lower-cost eddy covariance measurements with identical instrumentation, accounting for a total of seventy eight site-years of data. The objective of this dataset is to provide observational data on the differences of meteorological conditions, carbon, water and energy balances of adjacent agroforestry and open cropland or grassland sites in five distinct regions of Germany. This extensive, continuous dataset can be used to study ecosystem properties and the potential benefits of agroforestry. It can also be used to parametrize models on crop and biomass productivity, or to evaluate the response of such agroecosystems to climate change scenarios, among other applications. Anticipated key users of this dataset are researchers in the fields of micrometeorology, eddy covariance, agronomy, and ecosystem modeling. This dataset can be accessed through https://doi.org/10.25625/A2Z8T8 (Callejas Rodelas et al., 2025b)
Evapotranspiration of an abandoned grassland in the Italian Alps: Modeling the impact of shrub encroachment
Full text linkThe sewer system of urban Maputo
No full textDuring three months information about the sewer system of Maputo was gathered, mostly at DNA, DAS, CRA, AdeM, AIAS and at the Municipality of Maputo. The information, consisting of reports, papers, maps, presentations and websites, was used to estimate the potential amount of wastewater in the sewer system of Urban Maputo. This wastewater could be available for reuse in Maputo, at the WWTP, being this the main purpose of the project “Sustainable freshwater supply in urbanizing Maputo, Mozambique” led by TU Delft, UNESCO-IHE and the Mozambican University UEM.The sewer network consists of system one and system two. System one was built by the Portuguese in the 40s as a drainage system, but nowadays it functions as a combined sewer and it discharges directly into the bay. System two, built by DHV, a Dutch consultancy firm, in the 80s consists of sewer lines, a WWTP and two pumping stations. These pumping stations are also supposed to pump a part of the water of system one to the WWTP. However, because of sand in the pipes the pumping stations are not being operated.The billed amount of drinking water was used to calculate the flow in systems one and two. These data were obtained per neighbourhood and multiplied by 0.8, a guideline in Maputo for the amount of drinking water ending up in the sewers. For the water flowing in the sewer network, three cases are estimated, the actual status, system two completely working and the total volume of system one and two. The actual flow into the WWTP is 3957 m3/day with 20,665 m3/day being directly discharged into the bay. If the pumping stations of system two were operating, 10,266 m3/day would flow to the WWTP and 14,357 m3/day would be directed into the bay (Figure 1). By measuring the amount of influent at the WWTP, using the existing Venturi meter, the calculations were validated. The measurements show a flow arriving to the WWTP in the order of the magnitude of the calculations .This influent is generated by approximately 38,000 users that are connected to the sewer system.The sewer network of Maputo has a few critical parts which should be repaired as soon as possible, and better maintained in the future. First of all the pumping station of system two should be turned on. Before this is possible the sand in the sewers in front pumping station two must be removed and the pipes should stay clean. Sand and plastic bags ends up in the sewer system through drains or open manholes. To overcome clogging, drains and manholes have to be better maintained.Another recommendation is to collect the wastewater being discharged by system one and convey it to the existing WWTP or to a new one. The municipality has plans for this but lacks financing.All the water which is collected by system two is conveyed to the WWTP, but the WWTP is not functioning well. There is white slime in the effluent and colourful tarnish, which is a sign of bacteria being present in the effluent. The effluent is either directly used for irrigation of crops, which poses a risk for human health, or directed to the estuary.At the moment there are detailed plans to introduce a sanitation fee, which is necessary to improve, operate and maintain the system. CRA has been working on introducing the fee for several years already and they expect to introduce it within the coming years.At least these thesis's citated our document: - http://resolver.tudelft.nl/uuid:a6a87995-d31c-4d34-a909-d84364a6165a - http://resolver.tudelft.nl/uuid:d07583ed-acd8-43ea-8575-550ac693c1b7Sustainable freshwater supply in urbanizing Maputo, Mozambiqu
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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