scholarly journals Snow-Distribution Modelling in the Ammassalik Region, South East Greenland

2003 ◽  
Vol 34 (1-2) ◽  
pp. 1-16 ◽  
Author(s):  
B. Hasholt ◽  
G.E. Liston ◽  
N.T. Knudsen
Keyword(s):  
Snow Water Equivalent ◽  
Transport Model ◽  
Digital Terrain Model ◽  
Climatic Conditions ◽  
Blowing Snow ◽  
Orographic Effects ◽  
Terrain Model ◽  
Snow Distribution ◽  
Western Side ◽  
Snow Transport

The Ammassalik region is characterized by a strong alpine relief, with altitudes up to 1,000 m. Glaciers are located mainly on the western side of ridges. The climate is low arctic, with annual precipitation amounts of more than 1,000 mm, which falls mainly as snow. Furthermore very strong storms occur frequently throughout the region. All together these factors support strong snow redistribution by wind, which likely explains the glacier locations, and also explains the observed regional runoff differences. The aim of this study is to apply the Liston & Sturm snow-transport model (SnowTran-3D) to elucidate the snow distribution according to the actual climatic conditions. A digital terrain model was used to determine the terrain forcing of the wind field. Precipitation data from the Ammassalik meteorological station were corrected for aerodynamic errors and orographic effects. Wind, temperature and humidity were obtained from a station located on a nunatak 515 m.a.s.l. at the equilibrium line on the Mittivakkat Glacier. The recorded winter accumulation (balance) of snow on the glacier was used for model calibration and testing. Significant snow transport from east-facing slopes to west-facing slopes was confirmed by the model. The drift accumulations were greatest at the head of the glacier, just on the lee side of the ridge east of the glacier. In some areas, as much as 10% of the precipitation was returned to the atmosphere by blowing-snow sublimation. An average snow water equivalent of 113 cm was obtained (not including some minor areas having snow depths as great as 4 m). These results compare well with glacier observations of 114 cm collected in May 1998 (during the field survey the 4 m areas are omitted because of crevasse hazards). Future work will use the model to test scenarios that include changes in wind regime. 1

scholarly journals A snow-transport model for complex terrain

1998 ◽  
Vol 44 (148) ◽  
pp. 498-516 ◽  
Author(s):  
Glen E. Liston ◽  
Matthew Sturm
Keyword(s):  
Snow Depth ◽  
Depth Distribution ◽  
Snow Water Equivalent ◽  
Transport Model ◽  
Vegetation Type ◽  
Cold Season ◽  
Snow Accumulation ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Snow Transport

AbstractAs part of the winter environment in middle- and high-latitude regions, the interactions between wind, vegetation, topography and snowfall produce snow covers of non-uniform depth and snow water-equivalent distribution. A physically based numerical snow-transport model (SnowTran-3D) is developed and used to simulate this three-dimensional snow-depth evolution over topographically variable terrain. The mass-transport model includes processes related to vegetation snow-holding capacity, topographic modification of wind speeds, snow-cover shear strength, wind-induced surface-shear stress, snow transport resulting from saltation and suspension, snow accumulation and erosion, and sublimation of the blowing and drifting snow. The model simulates the cold-season evolution of snow-depth distribution when forced with inputs of vegetation type and topography, and atmospheric foreings of air temperature, humidity, wind speed and direction, and precipitation. Model outputs include the spatial and temporal evolution of snow depth resulting from variations in precipitation, saltation and suspension transport, and sublimation. Using 4 years of snow-depth distribution observations from the foothills north of the Brooks Range in Arctic Alaska, the model is found to simulate closely the observed snow-depth distribution patterns and the interannual variability.

Wind effects on the spatial distribution of snow and seasonal water balance in two Mediterranean basins

2020 ◽  
Author(s):  
Fabiola Pinto Escobar ◽  
Pablo A. Mendoza ◽  
Thomas E. Shaw ◽  
Jesús Revuelto ◽  
Keith Musselman ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Water Balance ◽  
Snow Water Equivalent ◽  
Climatic Conditions ◽  
Snow Accumulation ◽  
Distributed Model ◽  
Future Research ◽  
Blowing Snow ◽  
Wind Effects ◽  
Terrestrial Lidar

<p>Snow water equivalent is highly heterogeneous due to the spatial distribution of precipitation, local topographic characteristics, effects of vegetation, and wind. In particular, the latter has important effects on such distribution, controlling the preferential deposition of snowfall, transport (either by saltation or suspension) on the ground, and sublimation of blowing snow. In this work, we analyze the effects of incorporating redistribution by wind transport when modeling the seasonal water balance in two experimental catchments: (i) the Izas catchment (0.33 km²), located in the Spanish Pyrenees, with an elevation range of 2000-2300 m a.s.l., and (ii) Las Bayas catchment (2.45 km²), located in the extratropical Andes Cordillera (Chile) and elevation between 3400 and 3900 m a.s.l. After assessing model simulations using time series of snow depth and terrestrial lidar scans, we examine the water balance at the annual and seasonal scales, quantifying the different fluxes that govern snow accumulation and melting with a spatially distributed model that considers the physics of transport and the sublimation of blowing snow. Moreover, we characterize the sensitivity of dominant processes to changes in precipitation and temperature. The results of this investigation have important implications on current and future research, allowing to contrast wind effects in the spatio-temporal patterns of accumulation and melting in alpine and subalpine areas, identifying those processes that will be most affected under projected climatic conditions.</p>

scholarly journals Shifting Hydrological Processes in a Canadian Agroforested Catchment due to a Warmer and Wetter Climate

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 739
Author(s):  
Okan Aygün ◽  
Christophe Kinnard ◽  
Stéphane Campeau ◽  
Sebastian A. Krogh
Keyword(s):  
Climate Change ◽  
Snow Water Equivalent ◽  
Hydrological Processes ◽  
Blowing Snow ◽  
River Catchment ◽  
Annual Peak ◽  
Temperature And Precipitation ◽  
Physically Based ◽  
Snow Water ◽  
Snow Transport

This study examines the hydrological sensitivity of an agroforested catchment to changes in temperature and precipitation. A physically based hydrological model was created using the Cold Regions Hydrological Modelling platform to simulate the hydrological processes over 23 years in the Acadie River Catchment in southern Québec. The observed air temperature and precipitation were perturbed linearly based on existing climate change projections, with warming of up to 8 °C and an increase in total precipitation up to 20%. The results show that warming causes a decrease in blowing snow transport and sublimation losses from blowing snow, canopy-intercepted snowfall and the snowpack. Decreasing blowing snow transport leads to reduced spatial variability in peak snow water equivalent (SWE) and a more synchronized snow cover depletion across the catchment. A 20% increase in precipitation is not sufficient to counteract the decline in annual peak SWE caused by a 1 °C warming. On the other hand, peak spring streamflow increases by 7% and occurs 20 days earlier with a 1 °C warming and a 20% increase in precipitation. However, when warming exceeds 1.5 °C, the catchment becomes more rainfall dominated and the peak flow and its timing follows the rainfall rather than snowmelt regime. Results from this study can be used for sustainable farming development and planning in regions with hydroclimatic characteristics similar to the Acadie River Catchment, where climate change may have a significant impact on the dominating hydrological processes.

scholarly journals Evaluation of the wind erosion risks in GIS

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.

scholarly journals A snow-transport model for complex terrain

1998 ◽  
Vol 44 (148) ◽  
pp. 498-516 ◽  
Author(s):  
Glen E. Liston ◽  
Matthew Sturm
Keyword(s):  
Snow Depth ◽  
Depth Distribution ◽  
Snow Water Equivalent ◽  
Transport Model ◽  
Vegetation Type ◽  
Cold Season ◽  
Snow Accumulation ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Snow Transport

AbstractAs part of the winter environment in middle- and high-latitude regions, the interactions between wind, vegetation, topography and snowfall produce snow covers of non-uniform depth and snow water-equivalent distribution. A physically based numerical snow-transport model (SnowTran-3D) is developed and used to simulate this three-dimensional snow-depth evolution over topographically variable terrain. The mass-transport model includes processes related to vegetation snow-holding capacity, topographic modification of wind speeds, snow-cover shear strength, wind-induced surface-shear stress, snow transport resulting from saltation and suspension, snow accumulation and erosion, and sublimation of the blowing and drifting snow. The model simulates the cold-season evolution of snow-depth distribution when forced with inputs of vegetation type and topography, and atmospheric foreings of air temperature, humidity, wind speed and direction, and precipitation. Model outputs include the spatial and temporal evolution of snow depth resulting from variations in precipitation, saltation and suspension transport, and sublimation. Using 4 years of snow-depth distribution observations from the foothills north of the Brooks Range in Arctic Alaska, the model is found to simulate closely the observed snow-depth distribution patterns and the interannual variability.

A renovated model for spatial analysis of pollutant runoff loads in agricultural watershed

1998 ◽  
Vol 38 (10) ◽  
pp. 207-214 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dhong Il Jung ◽  
Cho Hee Yoon
Keyword(s):  
Stream Water ◽  
Digital Terrain Model ◽  
Pollution Sources ◽  
Agricultural Watershed ◽  
Water Model ◽  
Digital Information ◽  
Gis Technology ◽  
Terrain Model ◽  
Unit Loading ◽  
Pollutant Discharge

Runoff loads of pollutant in agricultural watersheds were spatially analyzed by using geographic information system(GIS) technology. The topological relationship between pollution sources in the watershed was, first of all, identified by using the developed digital map of land use and then the pollutant loads generated from each source was estimated by applying a conventional unit loading factor on the obtained digital information of pollution sources. To evaluate the loads delivered from spatially distributed pollution sources to monitoring stations in down stream via surface of watershed, a renovated empirical model incorporated with the information of pollutant discharge path was developed through introducing a digital terrain model(DTM) technique. In this model, the function of degradation of pollution loads during delivery process was simplified so that each watershed could have a basin-wide self-purification capacity which would be considered to be possessed inherently in each watershed and could retard the discharge of pollutants from sources generated to stream water. Model credibility showed good consistency with comparing the simulated values with observed data. Monte Carlo optimizing technique made it possible to estimate the basin-wide self-purification coefficients.

scholarly journals Blowing and drifting snow in Alpine terrain: numerical simulation and related field measurements

1998 ◽  
Vol 26 ◽  
pp. 174-178 ◽  
Author(s):  
Peter Gauer
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Three Dimensional ◽  
Field Measurements ◽  
Blowing Snow ◽  
Related Field ◽  
Drifting Snow ◽  
Physically Based ◽  
Snow Transport

A physically based numerical model of drifting and blowing snow in three-dimensional terrain is developed. The model includes snow transport by saltation and suspension. As an example, a numerical simulation for an Alpine ridge is presented and compared with field measurements.

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

Forests ◽  
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.

scholarly journals DTM-based analysis of the spatial distribution of topolineaments

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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