On the extraction of channel networks from digital elevation data

Abstract.Glacier mass balance models rely on accurate spatial calculation of input data, in particular air temperature. Lower temperatures (the so-called glacier cooling effect) and lower temperature variability (the so-called glacier damping effect) generally occur over glaciers compared to ambient conditions. These effects, which depend on the geometric characteristics of glaciers and display a high spatial and temporal variability, have been mostly investigated on medium to large glaciers so far, while observations on smaller ice bodies ( < 0.5 km 2 ) are scarce. Using a data set from eight on-glacier and four off-glacier weather stations, collected in the summers of 2010 and 2011, we analyzed the air temperature variability and wind regime over three different glaciers in the Ortles-Cevedale. The magnitude of the cooling effect and the occurrence of katabatic boundary layer (KBL) processes showed remarkable differences among the three ice bodies, suggesting the likely existence of important reinforcing mechanisms during glacier decay and fragmentation. The methods proposed by Greuell and Böhm (1998) and Shea and Moore (2010) for calculating on-glacier temperature from off-glacier data did not fully reproduce our observations. Among them, the more physically based procedure of Greuell and Böhm (1998) provided the best overall results where the KBL prevails, but it was not effective elsewhere (i.e., on smaller ice bodies and close to the glacier margins). The accuracy of air temperature estimations strongly impacted the results from a mass balance model which was applied to the three investigated glaciers. Most importantly, even small temperature deviations caused distortions in parameter calibration, thus compromising the model generalizability.

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“…A map of the FPL was calculated from this DEM, using algorithms developed for drainage area calculations (Fig. 2, Tarboton et al, 1991). …”

Section: Calculation Of On-glacier Temperature From Off-site Datamentioning

confidence: 99%

Air temperature variability over three glaciers in the Ortles–Cevedale (Italian Alps): effects of glacier fragmentation, comparison of calculation methods, and impacts on mass balance modeling

et al. 2015

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“…It is also known that digital elevation data and other spatial data sets are subject to inherent errors (Carlisle, 2005). Furthermore, modelling karstic areas using a DEM is more difficult than modelling normal landscapes, due to sinks in the DEM that are usually explained as errors influenced by the rounding of the elevations to the nearest integer value (Tarboton et al, 1991). In hydrogeomorphic applications it is a common practice to remove all such digital depressions in DEMs.…”

Section: Introductionmentioning

confidence: 99%

Geomorphic mapping in endorheic catchments in the Spanish Pyrenees: An integrated GIS analysis of karstic features

2009

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A B S T R A C TDigital elevation models (DEMs) can be a useful tool to assess morphologically and hydrologically active processes. This paper presents a method to obtain accurate DEMs, an analysis of DEM errors and the benefits of GIS techniques for mapping geomorphological features and active processes in the karstic endorheic catchment with three permanent lakes (Estaña lakes) in the External Ranges of the Spanish Pyrenees. Field work revealed the lack of accuracy in the original DEM. A method was then proposed to obtain a hydrologically correct DEM using a Total Topographic Station (TTS) and a Global Positioning System (GPS). On a regular grid, 246 topographic points were recorded with a GPS and 237 points were measured with a TTS on areas of gentle slope. The mean and standard deviation of the error of the corrected DEM were -1.5 and 3.2 m, respectively. By using a combined flow algorithm, a flow accumulation map was derived from the corrected DEM and the study area was Hence, the proposed methodology including DEM correction is useful for an accurate assessment of topographical and geomorphological features in karstic environments.2

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“…Furthermore, there are often numerous valleys, which are not cartographically marked as fluvial channels despite their ability to collect and transport flow. For these reasons, the first-order streams called ''fingertip'' by Horton (1945) or ''exterior links'' by Shreve (1966) and Tarboton et al (1991) should be included in drainage network studies. Many authors pointed out this in their studies (Horton 1945;Melton 1957;Lubowe 1964;Krumbein and Shreve 1970;Mark 1983;Javed et al 2009;Khanday and Javed 2016).…”

Section: Introductionmentioning

confidence: 99%

Hydrological investigations in the semi-arid Makhawan watershed, using morphometry

Khanday

Javed

2017

Appl Water Sci

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In order to understand the hydrological behavior of a catchment area, morphometric analysis of the drainage basin plays an important role to expresses the geology, geomorphology and structural antecedents. In the present study, morphometric analysis and its influence on hydrology were carried out in Makhawan watershed, Central India, using SRTM, remote sensing and GIS. SRTM data were used for preparation of DEM, slope and aspect maps. DEM was used to delineate the watershed limits and to extract the channel network, which was later updated using IRS 1D LISS III data. The hydrological module in ArcGIS was used for calculation of watershed and morphometric parameters, under linear, relief and aerial aspects. The watershed shows dendritic-to-sub-dendritic drainage pattern; however, parallel-to-sub-parallel pattern developed locally which may be due to rejuvenation of streams in mature stage with moderate drainage texture. High drainage density in the watershed is observed over impermeable subsurface material, sparse vegetation with high relief; whereas, low drainage density is found over permeable subsurface material and low relief. It has been found that low relief with low drainage density areas are favorable sites for more groundwater prospects.

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On the extraction of channel networks from digital elevation data

Cited by 958 publications

References 22 publications

Air temperature variability over three glaciers in the Ortles–Cevedale (Italian Alps): effects of glacier fragmentation, comparison of calculation methods, and impacts on mass balance modeling

Air temperature variability over three glaciers in the Ortles–Cevedale (Italian Alps): effects of glacier fragmentation, comparison of calculation methods, and impacts on mass balance modeling

Geomorphic mapping in endorheic catchments in the Spanish Pyrenees: An integrated GIS analysis of karstic features

Hydrological investigations in the semi-arid Makhawan watershed, using morphometry

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