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Start Over Creator de Lima, João L.M.P.

2. Improving the positional accuracy of drainage networks extracted from Global Digital Elevation Models using OpenStreetMap data

Creator:
Monteiro, Elisabete S.V., Fonte, Cidália C., and de Lima, João L.M.P.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
drainage networks, GDEMs, OpenStreetMap, and positional accuracy
Language:
Slovak
Description:
Drainage networks allow the extraction of topographic parameters that are useful for basins characterization and necessary for hydrologic modelling. One way to obtain drainage networks is by their extraction from Digital Elevation Models (DEMs). However, it is common that no freely available DEMs at regional or national level exist. One way to overcome this situation is to use the available free Global Digital Elevation Models (GDEMs). However, these datasets have relatively low spatial resolutions, 30 and 90 meters for ASTER and SRTM, respectively, and it has been shown that their accuracy is relatively low in several regions (e.g., Kääb, 2005; Mukul et al., 2017). In this study a methodology is presented to improve the positional accuracy of the drainage networks extracted from the GDEMs using crowdsourced data available in the collaborative project OpenStreetMap (OSM). In this approach only free and global datasets are used, enabling its application to any location of the world. The methodology uses elevation points derived from the GDEMs and the water lines extracted from the collaborative project OSM to generate new DEMs, from which new water lines are obtained. The methodology is applied to two study areas and the positional accuracy of the used data and the obtained results are assessed using reference data.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Revisiting simple methods to estimate drop size distributions: a novel approach based on infrared thermography

Creator:
de Lima, João L.M.P., Silva Jr., Valdemir P., de Lima, M. Isabel P., Abrantes, João R.C.B., and Montenegro, Abelardo A.A.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
rainfall, thermography, drop size distributions, and drop diameters
Language:
Slovak
Description:
The infrared thermography has been successfully applied as a tool for high resolution imaging in different hydrological studies. This exploratory experimental study aimed at evaluating the possibility of using infrared thermography to determine the diameter of raindrops. Rain samples are collected on a pre-heated acrylic board, which is exposed to rain during an instant, and thermograms are recorded. The area of the thermal stains (''signatures'' of the raindrops) emerging on the board is measured and converted to drop diameters, applying a calibration equation. Diameters of natural raindrops estimated using this technique were compared with laser disdrometer measurements; the Nash-Sutcliffe efficiency coefficient was used for evaluating the match between the resulting histograms of drop size distribution. Results confirm the usefulness of this simple technique for sizing and counting raindrops, although it is unsatisfactory in light rain or drizzle.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Using thermal tracers to estimate flow velocities of shallow flows: laboratory and field experiments

Creator:
de Lima, Rui L.P., Abrantes, João R.C.B., de Lima, João L.M.P., and de Lima, M. Isabel P.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
shallow flow velocities, thermal tracer, infrared thermography, and flow visualization
Language:
Slovak
Description:
Accurate measurement of shallow flows is important for hydraulics, hydrology and water resources management. The objective of this paper is to discuss a technique for shallow flow and overland flow velocity estimation that uses infrared thermography. Laboratory flumes and different bare, vegetated and paved field surfaces were used to test the technique. Results show that shallow flow surface velocities estimated using thermal tracers and infrared technology are similar to estimates obtained using the Acoustic Doppler Velocimeter; similar results were also obtained for overland flow velocity estimates using thermography, here comparing with the dye tracer technique. The thermographic approach revealed some potential as a flow visualization technique, and leaves space for future studies and research.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public