Search results for "0208 environmental biotechnology"

Spatial Distribution of Soil Hydrological Properties in the Kilombero Floodplain, Tanzania

2017

Analysis and interpretation of soil properties dynamics is a keystone in understanding the hydrologic responses and yield potential of floodplain wetlands. This study characterizes the distribution and spatial trends of selected soil physical properties in the Kilombero floodplain, Tanzania. A total of 76 composite soil samples were taken from 0 to 20 cm and 20 to 40 cm depth in a regular grid design across three hydrological zones, related to flooding intensity defined as fringe, middle, and riparian during the rainy season of 2015. The samples were analyzed for soil texture, bulk density, organic carbon, and saturated hydraulic conductivity. Seasonal soil moisture content was monitored at…

Factors Influencing Point Measurement of Near-surface Saturated Soil Hydraulic Conductivity in a Small Sicilian Basin

2017

Hydraulic conductivity of saturated soil, Ks, controls many hydrological processes. Parameterization of basin hydrological models in terms of Ks is complicated and uncertain owing to the very high spatial variability of this soil property. A small Sicilian basin was intensively sampled by the simplified falling head technique to obtain spatially distributed Ks data, and an attempt to explain their spatial variability on the basis of soil physical characteristics, digital elevation model-derived topographic attributes and land cover was carried out. High Ks values were obtained when clay content was low and both elevation and mean slope were high. Moreover, differences in Ks among land cover…

Estimating saturated soil hydraulic conductivity by the near steady-state phase of a Beerkan infiltration test

2017

Abstract Single-ring infiltration experiments carried out in the field, such as the Beerkan runs, allow easy and inexpensive characterization of soil hydraulic properties, and specifically saturated soil hydraulic conductivity, Ks, by maintaining the functional connection of the sampled soil volume with the surrounding soil. However, a single infiltration experiment is not enough to determine Ks. The simplest way to obtain the necessary additional data is based on the assessment of the soil texture and structure characteristics. In this investigation, a simplified method, named SSBI (Steady version of the Simplified method based on a Beerkan infiltration run), was developed to estimate Ks b…

Testing a new automated single ring infiltrometer for Beerkan infiltration experiments

2015

International audience; The Beerkan method along with BEST algorithms is an alternative technique to conventional laboratory or field measurements for rapid and low-cost estimation of soil hydraulic properties. The Beerkan method is simple to conduct but requires an operator to repeatedly pour known volumes of water through a ring positioned at the soil surface. A cheap infiltrometer equipped with a data acquisition system was recently designed to automate Beerkan infiltration experiments. In this paper, the current prototype of the automated infiltrometer was tested to validate its applicability to the Beerkan infiltration experiment under several experimental circumstances. In addition, t…

Challenges in the atmospheric characterization for the retrieval of spectrally resolved fluorescence and PRI region dynamics from space

2021

Abstract In the coming years, Earth Observation missions like the FLuorescence EXplorer (FLEX) will acquire the radiance signal from the visible to the near-infrared at a very high spectral resolution, enabling exciting prospects for new insights in satellite-based photosynthetic studies. In this context, the process of de-coupling atmospheric and vegetation-related spectral signatures will become essential to guarantee a reliable estimation of the vegetation photosynthetic activity from space. Dynamic changes related to the vegetation photosynthetic status result in subtle contributions to the top of atmosphere radiance signal, e.g. due to the emission of the solar-induced chlorophyll fluo…

New stage-discharge relationship for inclined non-rectangular weirs

2018

Abstract In this paper, the outflow process of inclined non-rectangular weirs is studied applying the dimensional analysis and the incomplete self-similarity theory. At first, a new stage-discharge equation, applicable for the non-rectangular weirs having a different geometrical shape (parabolic, semicircular, inverted semicircular), is theoretically deduced using a characteristic width. Then, this power stage-discharge relationship (Eq. (17) ) is calibrated and tested using measurements carried out by Raiknar for parabolic, semicircular and inverted semicircular weirs having different inclination respect to the vertical (10°, 20°, 30°, 40° and 45°). For each geometrical shape, the analysis…

Modeling accident risk at the road level through zero-inflated negative binomial models: A case study of multiple road networks

2021

Abstract This paper presents a case study carried out in multiple cities of the Valencian Community (Spain) to determine the effect of sociodemographic and road characteristics on traffic accident risk. The analyzes are performed at the road segment level, considering the linear network representing the road structure of each city as a spatial lattice. The number of accidents observed in each road segment from 2010 to 2019 is taken as the response variable, and a zero-inflated modeling approach is considered. Count overdispersion and spatial dependence are also accounted for. Despite the complexity and sparsity of the data, the fitted models performed considerably well, with few exceptions.…

Some links between conditional and coregionalized multivariate Gaussian Markov random fields

2020

Abstract Multivariate disease mapping models are attracting considerable attention. Many modeling proposals have been made in this area, which could be grouped into three large sets: coregionalization, multivariate conditional and univariate conditional models. In this work we establish some links between these three groups of proposals. Specifically, we explore the equivalence between the two conditional approaches and show that an important class of coregionalization models can be seen as a large subclass of the conditional approaches. Additionally, we propose an extension to the current set of coregionalization models with some new unexplored proposals. This extension is able to reproduc…

Spatio-temporal statistical methods in environmental and biometrical problems

2017

This is the editorial letter for the Special Issue dedicated to the VIII International Workshop on Spatio-temporal Modelling (METMAVIII) which took place in Valencia (Spain) from 1 to 3 June 2016, and to the second Galician-Portuguese meeting of Biometry, with applications to Health Sciences, Ecology and Environmental Sciences (BIOAPP2016) held in Santiago de Compostela (Spain), 30–2 July 2016. This special issue summarises and discusses selected peer-reviewed contributions related to spatial and spatio-temporal statistical methodologies comprising both new methodological approaches and a wide range of applications related to environmental and biometrical problems. Point processes, lattice …

2018

Abstract. In situ cloud observations at mountain-top research stations regularly measure ice crystal number concentrations (ICNCs) orders of magnitudes higher than expected from measurements of ice nucleating particle (INP) concentrations. Thus, several studies suggest that mountain-top in situ cloud microphysical measurements are influenced by surface processes, e.g., blowing snow, hoar frost or riming on snow-covered trees, rocks and the snow surface. This limits the relevance of such measurements for the study of microphysical properties and processes in free-floating clouds. This study assesses the impact of surface processes on in situ cloud observations at the Sonnblick Observatory in…