scholarly journals Effects of digital elevation model spatial resolution on distributed calculations of solar radiation loading on a High Arctic glacier

2009 ◽  
Vol 55 (194) ◽  
pp. 973-984 ◽  
Author(s):  
Neil Arnold ◽  
Gareth Rees
Keyword(s):  
High Resolution ◽  
Solar Radiation ◽  
High Arctic ◽  
Airborne Lidar ◽  
Distributed Model ◽  
Height Measurement ◽  
Glacier Surface ◽  
Direct Beam ◽  
Digital Elevation ◽  
The Impact

AbstractHigh-resolution airborne lidar data are used to produce digital elevation models (DEMs) of an arctic valley glacier (midre Lovénbreen, Svalbard) at resolutions of 2.5–2000 m, using three different interpolation schemes. These data are used in a distributed model of solar radiation loading for glaciers. When the mean of all lidar measurements within a DEM cell is used to calculate cell height, the differences between the finest- (2.5 m) and coarsest-resolution (2000 m) DEMs for the calculated annual whole-glacier spatial means of total potential direct-beam solar radiation, potential duration of direct-beam solar radiation, and intensity of potential direct-beam solar radiation are 20%, 56% and −23% of the 2.5 m DEM values respectively. A resolution change from 2.5 m to 200 m affects the whole-glacier spatial mean summer net solar radiative flux by an average of 5%, and the summer melt production from the glacier by an average of 3% compared with the 2.5 m DEM values, for the years 2001–03. These changes are largely driven by underestimation of shading by surrounding topography at coarser DEM resolutions. This dependency is reduced in the second and third interpolation schemes, especially at resolutions finer than 50 m, which use the maximum lidar height measurement in some or all DEM cells. These results suggest that resolutions of ∼50 m are the coarsest that should be adopted in high-resolution glacier surface energy-balance models for glaciers of similar size and in similar topographic situations to midre Lovénbreen, and that the impact of DEM resolution on calculated solar radiation receipts can be reduced by an appropriate choice of DEM interpolation scheme.

scholarly journals Thermal structure and drainage system of a small valley glacier (Tellbreen, Svalbard), investigated by ground penetrating radar

2011 ◽  
Vol 5 (1) ◽  
pp. 139-149 ◽  
Author(s):  
K. Bælum ◽  
D. I. Benn
Keyword(s):  
Ground Penetrating Radar ◽  
Thermal Structure ◽  
Drainage System ◽  
High Arctic ◽  
Differential Gps ◽  
Glacier Surface ◽  
Digital Elevation ◽  
Drainage Channels ◽  
Ground Penetrating ◽  
Subglacial Drainage

Abstract. Proglacial icings accumulate in front of many High Arctic glaciers during the winter months, as water escapes from englacial or subglacial storage. Such icings have been interpreted as evidence for warm-based subglacial conditions, but several are now known to occur in front of cold-based glaciers. In this study, we investigate the drainage system of Tellbreen, a 3.5 km long glacier in central Spitsbergen, where a large proglacial icing develops each winter, to determine the location and geometry of storage elements. Digital elevation models (DEMs) of the glacier surface and bed were constructed using maps, differential GPS and ground penetrating radar (GPR). Rates of surface lowering indicate that the glacier has a long-term mass balance of −0.6 ± 0.2 m/year. Englacial and subglacial drainage channels were mapped using GPR, showing that Tellbreen has a diverse drainage system that is capable of storing, transporting and releasing water year round. In the upper part of the glacier, drainage is mainly via supraglacial channels. These transition downglacier into shallow englacial "cut and closure" channels, formed by the incision and roof closure of supraglacial channels. Below thin ice near the terminus, these channels reach the bed and contain stored water throughout the winter months. Even though no signs of temperate ice were detected and the bed is below pressure-melting point, Tellbreen has a surface-fed, channelized subglacial drainage system, which allows significant storage and delayed discharge.

scholarly journals Merging ground-based sunshine duration observations with satellite cloud and aerosol retrievals to produce high-resolution long-term surface solar radiation over China

2021 ◽  
Vol 13 (3) ◽  
pp. 907-922
Author(s):  
Fei Feng ◽  
Kaicun Wang
Keyword(s):  
Standard Deviation ◽  
High Resolution ◽  
Solar Radiation ◽  
Spatial Resolution ◽  
Sunshine Duration ◽  
Ordinary Least Squares ◽  
Cloud Fraction ◽  
Surface Solar Radiation ◽  
The Impact

Abstract. Although great progress has been made in estimating surface solar radiation (Rs) from meteorological observations, satellite retrieval, and reanalysis, getting best-estimated long-term variations in Rs are sorely needed for climate studies. It has been shown that Rs data derived from sunshine duration (SunDu) can provide reliable long-term variability, but such data are available at sparsely distributed weather stations. Here, we merge SunDu-derived Rs with satellite-derived cloud fraction and aerosol optical depth (AOD) to generate high-spatial-resolution (0.1∘) Rs over China from 2000 to 2017. The geographically weighted regression (GWR) and ordinary least-squares regression (OLS) merging methods are compared, and GWR is found to perform better. Based on the SunDu-derived Rs from 97 meteorological observation stations, which are co-located with those that direct Rs measurement sites, the GWR incorporated with satellite cloud fraction and AOD data produces monthly Rs with R2=0.97 and standard deviation =11.14 W m−2, while GWR driven by only cloud fraction produces similar results with R2=0.97 and standard deviation =11.41 W m−2. This similarity is because SunDu-derived Rs has included the impact of aerosols. This finding can help to build long-term Rs variations based on cloud data, such as Advanced Very High Resolution Radiometer (AVHRR) cloud retrievals, especially before 2000, when satellite AOD retrievals are not unavailable. The merged Rs product at a spatial resolution of 0.1∘ in this study can be downloaded at https://doi.org/10.1594/PANGAEA.921847 (Feng and Wang, 2020).

scholarly journals Long-term observations of supraglacial streams on an Arctic glacier

2019 ◽  
Vol 65 (254) ◽  
pp. 900-911 ◽  
Author(s):  
Sarah L. St Germain ◽  
Brian J. Moorman
Keyword(s):  
Solar Radiation ◽  
Unmanned Aerial Vehicles ◽  
Aerial Imagery ◽  
Digital Elevation ◽  
Small Streams ◽  
Hydrological System ◽  
Arctic Glacier ◽  
The Impact ◽  
Stream Formation

AbstractSupraglacial streams are a significant part of the glacial hydrological system and important for understanding glacial hydrology and dynamics. Here we infer factors that influence the long-term development of perennial supraglacial streams, particularly in reference to canyon, incised and surface stream formation. Orthophotos and digital elevation models generated from high-resolution aerial imagery taken with unmanned aerial vehicles or piloted helicopters between 2010 and 2017 were used to compare seven streams on Fountain Glacier, Bylot Island, Canada over time. Results show canyon formation occurs from a combination of fluvial processes and the impact of solar radiation. The greater the discharge or slope, the faster the incision and higher the sinuosity. With greater sinuosity, the distance between the top of the valley banks increases, and cutoffs cause trapezoidal canyon-like valleys to form. Solar radiation causes the backward migration of the valley walls, further enhancing canyon area. Canyons are less likely to occur in areas of low discharge and slope. Less incised channels are also more likely to have water flow jumping the channel banks, changing the channel path. The presence of medial moraines and crevasses also increases rerouting of small streams. Lastly, windblown created snow-plugs may lead to stream diversion.

scholarly journals Investigation of the impact of simulated solar radiation on the micro- and nanoscale morphology and mechanical properties of a sheet moulded composite surface

2016 ◽  
Vol 34 (3) ◽  
pp. 641-649 ◽  
Author(s):  
Andrzej Sikora ◽  
Łukasz Bednarz ◽  
Tomasz Fałat ◽  
Marek Wałecki ◽  
Maria Adamowska
Keyword(s):  
High Resolution ◽  
Solar Radiation ◽  
Material Degradation ◽  
Significant Deterioration ◽  
Composite Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Applied Approach ◽  
Simulated Solar Radiation ◽  
The Impact

AbstractIn this paper we present the results of investigation of micro- and nanoscale degradation of a sheet moulded composite exposed to simulated solar radiation. Utilization of high resolution methods such as atomic force microscopy, optical profilometry and microcomputer tomography allowed us to provide the evidence of significant deterioration of the surface as well as the material few microns in depth. Additionally, the typically used macroscopic investigations, such as wettability and flexural strength, were performed to observe the impact of weathering process. It was also shown that high resolution techniques provide superior sensitivity of the material degradation detection. The particular effectiveness of the applied approach was related to the structure of investigated material, as due to its degradation, a number of voids appeared, causing a significant roughness increase. In addition, the impact of light radiation could be compared to other environmental conditions maintained in the climatic chamber. It should be underlined, that according to our knowledge, such a study has not been performed so far.

scholarly journals Sensitivity of geodetic glacier mass balance estimation to DEM void interpolation

2018 ◽  
Author(s):  
Robert McNabb ◽  
Christopher Nuth ◽  
Andreas Kääb ◽  
Luc Girod
Keyword(s):  
Mass Balance ◽  
Terrestrial Ecosystems ◽  
Glacier Mass Balance ◽  
Direct Impact ◽  
Glacier Surface ◽  
Southeast Alaska ◽  
Digital Elevation ◽  
Regional Basis ◽  
The Impact

Abstract. Glacier mass balance is a direct expression of climate change, with implications for sea level, ocean chemistry, oceanic and terrestrial ecosystems, and water resources. Traditionally, glacier mass balance has been estimated using in-situ measurements of changes in surface height and density at select locations on the glacier surface, or by comparing changes in surface height using repeat, full-coverage digital elevation models (DEMs), also called the geodetic method. DEMs often have gaps in coverage (voids) based on the nature of the sensor used and the surface being measured. The way that these voids are accounted for has a direct impact on the estimate of geodetic glacier mass balance, though a systematic comparison of different proposed methods has been heretofore lacking. In this study, we determine the impact and sensitivity of void-filling methods on estimates of volume change. Using two spatially complete, high-resolution DEMs over Southeast Alaska, USA, we compare 11 different void-filling methods on a glacier-by-glacier and regional basis. We find that a few methods introduce biases of up to 20 % in the regional results, while other methods give results very close (

Estimation of solar radiation from digital elevation model in area of rough topography

2016 ◽  
Vol 13 (5) ◽  
pp. 453-460 ◽  
Author(s):  
Lurwan Mahmoud Sabo ◽  
Norman Mariun ◽  
Hashim Hizam ◽  
Mohd Amran Mohd Radzi ◽  
Azmi Zakaria
Keyword(s):  
Solar Radiation ◽  
Digital Elevation Model ◽  
Spatial Data ◽  
Energy Planning ◽  
Solar Photovoltaic ◽  
Content Type ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Impact ◽  
Topographic Parameters

Purpose The purpose of this study is to evaluate the reliability of the technique for estimating solar radiation in areas of rough topography and to detect the source of error and means for improvement. Design/methodology/approach Spatial data of the study area in the form of digital elevation model (DEM) coupled with geographic information system (GIS) were used to estimate the monthly solar radiation at locations with rough topography. The generated data were compared with measured data collected from all the selected locations using NASA data. Findings The results show that the variation in topographic parameters has a strong influence on the amount of solar radiation received by two close locations. However, the method performed well for solar radiation estimated in the areas of rough topography. Research limitations/implications The proposed approach overestimates the monthly solar radiation as compared with NASA data due to the impact of topographic parameters accounted for by the model which are not accounted by conventional methods of measurements. This approach can be improved by incorporating the reflected component of radiation in the model used to estimate the solar radiation implemented in the GIS. Originality/value The approach of using GIS with DEM to estimate solar radiation enables to identify the spatial variability in solar radiation between two closest locations due to the influence of topographic parameters, and this will assist in proper energy planning and decision making for optimal areas of solar photovoltaic installation.

scholarly journals Evaluation of High-Resolution Satellite-Derived Solar Radiation Data for PV Performance Simulation in East Africa

2021 ◽  
Vol 13 (21) ◽  
pp. 11852
Author(s):  
Diane Palmer ◽  
Richard Blanchard
Keyword(s):  
High Resolution ◽  
Solar Radiation ◽  
East Africa ◽  
Solar Irradiance ◽  
Statistical Tests ◽  
Performance Simulation ◽  
Life Chances ◽  
Radiation Data ◽  
Electric Pressure ◽  
The Impact

Access to reliable, clean, modern cooking enhances life chances. One option is photovoltaic cooking systems. Accurate solar data are needed to ascertain to what extent these can satisfy the needs of local people. In this paper, we investigate how to choose the most accurate satellite-derived solar irradiance database for use in Africa. This is necessary because there is a general shortage of ground measurements for Africa. The solar data are needed to model the output of solar cooking systems, such as a solar panel, battery and electric pressure cooker. Four easily accessible global horizontal irradiation (GHI) satellite databases are validated against ground measurements using a range of statistical tests. The results demonstrate the impact of the mathematical measure used and the phenomenon of balancing errors. Fitting of the satellite model to the appropriate climate zone and/or nearby measurements improves accuracy, as does higher spatial and temporal resolution of input parameters. That said, all the four databases reviewed were found to be suitable for simulating PV yield in East Africa.

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