Areal melt and discharge modelling of Storglaciären, Sweden

A grid-based glacier melt-and-discharge model was applied to Storglaciären, a small valley glacier (3 km2) in northern Sweden, for the melt seasons of 1993 and 1994. The energy available for melt was estimated from a surface energy-balance model using meteorological data collected by automatic weather stations on the glacier. Net radiation and the turbulent heat fluxes were calculated hourly for every grid point of a 30 m resolution digital terrain model, using the measurements of temperature, humidity, wind speed and radiative fluxes on the glacier. Two different bulk approaches were used to calculate the turbulent fluxes and compared with respect to their impact on discharge simulations. Discharge of Storglaciären was simulated from calculated meltwater production and precipitation by three parallel linear reservoirs corresponding to the different storage properties of firn, snow and ice. The performance of the model was validated by comparing simulated discharge to measured discharge at the glacier snout. Depending on which parameterization of the turbulent fluxes was used, the timing and magnitude of simulated discharge was in good agreement with observed discharge, or simulated discharge was considerably underestimated in one year.

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The Conception of the Net Weather Station for Measuring the Microclimate of the Forest

Proccedings of 10th International Conference "Environmental Engineering" ◽

10.3846/enviro.2017.040 ◽

2017 ◽

Author(s):

Paweł Szymanski ◽

Michał Brach ◽

Marcin Szymanski ◽

Michał Smieja ◽

Wojciech O>ga

Keyword(s):

Meteorological Data ◽

Digital Terrain Model ◽

Main Idea ◽

Strongly Correlated ◽

Weather Station ◽

Current Time ◽

Terrain Model ◽

Digital Terrain ◽

Grid Points ◽

Sd Card

The project of meteorological station is designed to monitor the state of the weather on the selected (forest areas) as well as the colleting the data to analyze the dynamic of the changes weather parameters. The main idea presented in this paper, base on assumption that single weather station can be used as a part of net. The simultaneous and continuous measurement of many parameters such as temperature, pressure, humidity and sunlight located at grid points could work out finaly the weather map combined with the digital terrain model. The modern electronic make possible flexible connecting indywidual stations in subsytems and exchange of huge amount of inforamtion leading to build base knowledge. In the first part of the article it is presented the conception of the information system. In the next part there are are outlined the results of works with the prototype of the measure mode. Dedicated to applications in forestry prototype of device, can be used to measure temperature, pressure, humidity and sunlight. The additional features of the device are the possibility of writing data on micro SD card, supplemented with current time, day, and year. The design and research is a pilot, before the creation of a regular grid of sample plots with the use of many such devices. The objective is to gather accurate meteorological data from the interior of the forest-based geostatistical analysis, necessary for breeding purposes. Because of their design frames weather, it can be installed on most trees. Presented prototype of basic station used in the concept of measuring net, generates data from the sensors, which are strongly correlated with the compared professional station.

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Evaluation of the wind erosion risks in GIS

Soil and Water Research ◽

10.17221/2101-swr ◽

2008 ◽

Vol 2 (No. 1) ◽

pp. 10-14

Author(s):

J. Podhrázská ◽

I. Novotný

Keyword(s):

Wind Erosion ◽

Agricultural Land ◽

Meteorological Data ◽

Digital Terrain Model ◽

Climatic Conditions ◽

Topographic Maps ◽

Terrain Model ◽

Digital Terrain ◽

Potential Risks ◽

Information Database

The paper refers to the possibilities of the evaluation of the wind erosion risks by using a model created in GIS. The model exploits the pedological information database for determining the potential risks of soils by wind erosion. The following data are the database of the agricultural land use, meteorological data and the topographic maps for determining the direction of wind and climatic conditions. Using the data transferred to the graphic form, it is possible to create the digital terrain model and to regionalise the meteorological data. Consequently, the wind barriers are localised in the landscape and it is possible to create the zone of efficiency around each barrier (protecting the land from the erosive effects of the wind) according to the characteristics of their height and density.

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Geographic information system (GIS) procedure for preliminary delineation of debris-flow hazard areas from a digital terrain model, Madison County, Virginia

Open-File Report ◽

10.3133/ofr99336 ◽

1999 ◽

Author(s):

R.H. Campbell ◽

P.G. Chirico

Keyword(s):

Information System ◽

Geographic Information System ◽

Debris Flow ◽

Digital Terrain Model ◽

Geographic Information ◽

Terrain Model ◽

Madison County ◽

Digital Terrain ◽

Debris Flow Hazard

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The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover

Forests ◽

10.3390/f12030265 ◽

2021 ◽

Vol 12 (3) ◽

pp. 265

Author(s):

Mihnea Cățeanu ◽

Arcadie Ciubotaru

Keyword(s):

Forest Cover ◽

Initial Point ◽

Ground Surface ◽

Digital Terrain Model ◽

Morphological Data ◽

Sampling Density ◽

Terrain Model ◽

Digital Terrain ◽

Point Density ◽

The Impact

Laser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Terrain Model (DTM) via interpolation. This paper proposes a quantitative analysis of the accuracy of DTMs (and derived slope maps) obtained from LiDAR data and is focused on conditions common to most forestry activities (rough, steep terrain with forest cover). Three interpolation algorithms were tested: Inverse Distance Weighted (IDW), Natural Neighbour (NN) and Thin-Plate Spline (TPS). Research was mainly focused on the issue of point data density. To analyze its impact on the quality of ground surface modelling, the density of the filtered data set was artificially lowered (from 0.89 to 0.09 points/m2) by randomly removing point observations in 10% increments. This provides a comprehensive method of evaluating the impact of LiDAR ground point density on DTM accuracy. While the reduction of point density leads to a less accurate DTM in all cases (as expected), the exact pattern varies by algorithm. The accuracy of the LiDAR-derived DTMs is relatively good even when LiDAR sampling density is reduced to 0.40–0.50 points/m2 (50–60 % of the initial point density), as long as a suitable interpolation algorithm is used (as IDW proved to be less resilient to density reductions below approximately 0.60 points/m2). In the case of slope estimation, the pattern is relatively similar, except the difference in accuracy between IDW and the other two algorithms is even more pronounced than in the case of DTM accuracy. Based on this research, we conclude that LiDAR is an adequate method for collecting morphological data necessary for modelling the ground surface, even when the sampling density is significantly reduced.

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DTM-based analysis of the spatial distribution of topolineaments

Open Geosciences ◽

10.1515/geo-2020-0059 ◽

2020 ◽

Vol 12 (1) ◽

pp. 1185-1199

Author(s):

Mirosław Kamiński

Keyword(s):

Laser Scanning ◽

Digital Terrain Model ◽

Research Area ◽

Tectonic Structures ◽

Empirical Bayesian ◽

Scanning Method ◽

Empirical Bayesian Kriging ◽

Terrain Model ◽

Digital Terrain ◽

Airborne Laser

AbstractThe research area is located on the boundary between two Paleozoic structural units: the Radom–Kraśnik Block and the Mazovian–Lublin Basin in the southeastern Poland. The tectonic structures are separated by the Ursynów–Kazimierz Dolny fault zone. The digital terrain model obtained by the ALS (Airborne Laser Scanning) method was used. Classification and filtration of an elevation point cloud were performed. Then, from the elevation points representing only surfaces, a digital terrain model was generated. The model was used to visually interpret the course of topolineaments and their automatic extraction from DTM. Two topolineament systems, trending NE–SW and NW–SE, were interpreted. Using the kernel density algorithm, topolineament density models were generated. Using the Empirical Bayesian Kriging, a thickness model of quaternary deposits was generated. A relationship was observed between the course of topolineaments and the distribution and thickness of Quaternary formations. The topolineaments were compared with fault directions marked on tectonic maps of the Paleozoic and Mesozoic. Data validation showed consistency between topolineaments and tectonic faults. The obtained results are encouraging for further research.

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Production, Validation and Morphometric Analysis of a Digital Terrain Model for Lake Trichonis Using Geospatial Technologies and Hydroacoustics

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi10020091 ◽

2021 ◽

Vol 10 (2) ◽

pp. 91

Author(s):

Triantafyllia-Maria Perivolioti ◽

Antonios Mouratidis ◽

Dimitrios Terzopoulos ◽

Panagiotis Kalaitzis ◽

Dimitrios Ampatzidis ◽

...

Keyword(s):

Morphometric Analysis ◽

Ad Hoc ◽

Regional Scale ◽

Digital Terrain Model ◽

Relevant Information ◽

Relative Difference ◽

Systematic Observation ◽

Qualitative And Quantitative ◽

Terrain Model ◽

Digital Terrain

Covering an area of approximately 97 km2 and with a maximum depth of 58 m, Lake Trichonis is the largest and one of the deepest natural lakes in Greece. As such, it constitutes an important ecosystem and freshwater reserve at the regional scale, whose qualitative and quantitative properties ought to be monitored. Depth is a crucial parameter, as it is involved in both qualitative and quantitative monitoring aspects. Thus, the availability of a bathymetric model and a reliable DTM (Digital Terrain Model) of such an inland water body is imperative for almost any systematic observation scenario or ad hoc measurement endeavor. In this context, the purpose of this study is to produce a DTM from the only official cartographic source of relevant information available (dating back approximately 70 years) and evaluate its performance against new, independent, high-accuracy hydroacoustic recordings. The validation procedure involves the use of echosoundings coupled with GPS, and is followed by the production of a bathymetric model for the assessment of the discrepancies between the DTM and the measurements, along with the relevant morphometric analysis. Both the production and validation of the DTM are conducted in a GIS environment. The results indicate substantial discrepancies between the old DTM and contemporary acoustic data. A significant overall deviation of 3.39 ± 5.26 m in absolute bottom elevation differences and 0.00 ± 7.26 m in relative difference residuals (0.00 ± 2.11 m after 2nd polynomial model corrector surface fit) of the 2019 bathymetric dataset with respect to the ~1950 lake DTM and overall morphometry appear to be associated with a combination of tectonics, subsidence and karstic phenomena in the area. These observations could prove useful for the tectonics, geodynamics and seismicity with respect to the broader Corinth Rift region, as well as for environmental management and technical interventions in and around the lake. This dictates the necessity for new, extensive bathymetric measurements in order to produce an updated DTM of Lake Trichonis, reflecting current conditions and tailored to contemporary accuracy standards and state-of-the-art research in various disciplines in and around the lake.

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Refinement of interferometric SAR parameters using digital terrain model as an external reference

ISPRS Journal of Photogrammetry and Remote Sensing ◽

10.1016/j.isprsjprs.2021.02.017 ◽

2021 ◽

Vol 175 ◽

pp. 34-43

Author(s):

Jyunpei Uemoto

Keyword(s):

Digital Terrain Model ◽

Terrain Model ◽

Digital Terrain ◽

External Reference ◽

Interferometric Sar

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Modeling Streamflow and Sediment Loads with a Photogrammetrically Derived UAS Digital Terrain Model: Empirical Evaluation from a Fluvial Aggregate Excavation Operation

Drones ◽

10.3390/drones5010020 ◽

2021 ◽

Vol 5 (1) ◽

pp. 20

Author(s):

Joseph P. Hupy ◽

Cyril O. Wilson

Keyword(s):

Soil Erosion ◽

Point Cloud ◽

Empirical Evaluation ◽

Digital Terrain Model ◽

Surface Flow ◽

Sediment Loading ◽

Terrain Model ◽

Digital Terrain ◽

Statistical Measures ◽

Geospatial Datasets

Soil erosion monitoring is a pivotal exercise at macro through micro landscape levels, which directly informs environmental management at diverse spatial and temporal scales. The monitoring of soil erosion can be an arduous task when completed through ground-based surveys and there are uncertainties associated with the use of large-scale medium resolution image-based digital elevation models for estimating erosion rates. LiDAR derived elevation models have proven effective in modeling erosion, but such data proves costly to obtain, process, and analyze. The proliferation of images and other geospatial datasets generated by unmanned aerial systems (UAS) is increasingly able to reveal additional nuances that traditional geospatial datasets were not able to obtain due to the former’s higher spatial resolution. This study evaluated the efficacy of a UAS derived digital terrain model (DTM) to estimate surface flow and sediment loading in a fluvial aggregate excavation operation in Waukesha County, Wisconsin. A nested scale distributed hydrologic flow and sediment loading model was constructed for the UAS point cloud derived DTM. To evaluate the effectiveness of flow and sediment loading generated by the UAS point cloud derived DTM, a LiDAR derived DTM was used for comparison in consonance with several statistical measures of model efficiency. Results demonstrate that the UAS derived DTM can be used in modeling flow and sediment erosion estimation across space in the absence of a LiDAR-based derived DTM.

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