Using Landsat-5 thematic mapper and digital elevation data to determine the net radiation field of a Mountain Glacier

Gratton, Denis; Howarth, Philip J.; Marceau, Danielle J.

doi:10.1016/0034-4257(93)90073-7

Cited by 65 publications

(48 citation statements)

References 23 publications

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“…In this way, the adjacent slopes visible from the pixel will also contribute to the diffuse irradiance reaching the pixel. For instance, a part of the irradiance received by pixel P in Figure 4 (right) may be reflected towards pixel M. This component is often considered to be relatively insignificant and is neglected in most studies [31,38]. However, if the surface's cover is highly reflective (e.g., snow and ice) or in mountainous areas with deep valleys, it is important to estimate this component.…”

Section: Diffuse Irradiancementioning

confidence: 99%

“…However, if the surface's cover is highly reflective (e.g., snow and ice) or in mountainous areas with deep valleys, it is important to estimate this component. As an example, Gratton et al [31], showed that in a glacier basin between 10% and 25% of the total irradiance at any location was terrain irradiance for non-shadowed and large shadowed areas.…”

Section: Diffuse Irradiancementioning

confidence: 99%

“…Finally, topography changes the orientation of a target and therefore alters the illumination and viewing angles, which affect reflected radiance because of the surface anisotropic reflectance. Topographic effects are determined by the aspect and slope of the surface and the local horizon, and also by the geometry of the surrounding areas [31]. The topographic effects can be as important as the atmospheric effects [32].…”

Section: Introductionmentioning

confidence: 99%

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Modeling Top of Atmosphere Radiance over Heterogeneous Non-Lambertian Rugged Terrain

et al. 2015

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Topography affects the fraction of direct and diffuse radiation received on a pixel and changes the sun-target-sensor geometry, resulting in variations in the observed radiance. Retrieval of surface-atmosphere properties from top of atmosphere radiance may need to account for topographic effects. This study investigates how such effects can be taken into account for top of atmosphere radiance modeling. In this paper, a system for top of atmosphere radiance modeling over heterogeneous non-Lambertian rugged terrain through radiative transfer modeling is presented. The paper proposes an extension of "the four-stream radiative transfer theory" , 2007) mainly aimed at representing topography-induced contributions to the top of atmosphere radiance modeling. A detailed account for BRDF effects, adjacency effects and topography effects on the radiance modeling is given, in which sky-view factor and non-Lambertian reflected radiance from adjacent slopes are modeled precisely. The paper also provides a new formulation to derive the atmospheric coefficients from MODTRAN with only two model runs, to make it more computationally efficient and also avoiding the use of zero surface albedo as used in the four-stream radiative transfer theory. The modeling begins with four surface reflectance factors calculated by the Soil-Leaf-Canopy radiative transfer model SLC at the top of canopy and propagates them through the effects of the atmosphere, which is explained by six atmospheric coefficients, derived from MODTRAN radiative OPEN ACCESSRemote Sens. 2015, 7 8020 transfer code. The top of the atmosphere radiance is then convolved with the sensor characteristics to generate sensor-like radiance. Using a composite dataset, it has been shown that neglecting sky view factor and/or terrain reflected radiance can cause uncertainty in the forward TOA radiance modeling up to 5 (mW/m 2 ·sr·nm). It has also been shown that this level of uncertainty can be translated into an over/underestimation of more than 0.5 in LAI (or 0.07 in fCover) in variable retrieval.

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Section: Diffuse Irradiancementioning

confidence: 99%

Section: Diffuse Irradiancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling Top of Atmosphere Radiance over Heterogeneous Non-Lambertian Rugged Terrain

et al. 2015

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“…Likewise, if snow were Table 2. Land cover dependent weighted functions for the retrieval of albedo (a) from LANDSAT-TM-band-calculated reflectances (TM2 -TM7) (after: Gratton et al, 1993) Land cover type classified in the image of May, the land use from the October analyses was inserted. The resulting combined land use map, derived from the multitemporal LANDSAT-TM data set, is shown in Fig.…”

Section: Reflection [%]mentioning

confidence: 99%

“…The two LANDSAT-TM scenes from May and October were processed to provide albedo-maps of a spring and autumn situation, respectively, using the procedure of Gratton et al (1993). Weighted functions of the TM-Bands 2, 4 and 7, listed in Table 2, were used to calculate albedo values for different surface covers.…”

Section: Derivation Of Albedo Valuesmentioning

confidence: 99%

Use of remote sensing for hydrological parameterisation of Alpine catchments

Bach¹,

Braun²,

Lampart³

et al. 2003

Hydrol. Earth Syst. Sci.

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Physically-based water balance models require a realistic parameterisation of land surface characteristics of a catchment. Alpine areas are very complex with strong topographically-induced gradients of environmental conditions, which makes the hydrological parameterisation of Alpine catchments difficult. Within a few kilometres the water balance of a region (mountain peak or valley) can differ completely. Hence, remote sensing is invaluable for retrieving hydrologically relevant land surface parameters. The assimilation of the retrieved information into the water balance model PROMET is demonstrated for the Toce basin in Piemonte/Northern Italy. In addition to land use, albedos and leaf area indices were derived from LANDSAT-TM imagery. Runoff, modelled by a water balance approach, agreed well with observations without calibration of the hydrological model.

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Glacier fragmentation effects on surface energy balance and runoff: field measurements and distributed modelling

Jiskoot

Mueller

2012

Hydrological Processes

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In order to assess glacier runoff to the Upper Columbia River Basin (UCRB) and quantify energy balance effects of tributary-trunk detachment due to recession, we used field observations to develop a distributed melt model of Shackleton Glacier, Canadian Rockies. Field data were derived from meteorological stations, ablation and snowline measurements, and weather observations between 2004 and 2010. Katabatic wind speed and direction were linked to terrain heat advection and irradiance, potentially resulting in significant cross-glacier gradients in melt. A geographic information system-based distributed melt model, using standard energy balance components, was developed for the 2010 melt season. Benchmark model parameterisations were derived for clear, cloudy and overcast days. Novel model parameterisations include terrain irradiance using a sky view factor and an albedo mask, and a katabatic wind 'switch' with valley temperature thresholds. Modelled energy balance components suggest significant sensitivities to terrain irradiance and katabatic wind, in part related to cloudiness. Glacier-wide melt decreased by 10-15% when katabatic wind was turned off, with an interesting spatial pattern. Longwave radiation from valley walls increased local melt up to 30%, but net glacier-wide effects were <6%. Daily glacier melt was 0.1-0.8 million m 3 w.e. day À1 and peaked in early August. Net 2010 planar-area melt was 38-50 million m 3 w.e., depending on cold storage, whereas slope-corrected-area melt was~4% higher. Our results indicate that katabatic wind and terrain are important in calculations of ablation in fragmenting glacier systems and that late-summer glacier contribution to UCRB runoff at Mica Dam is~25%. RESULTS: MELT MODEL Energy balance componentsThe relative contribution of modelled energy balance components to melt in the early, middle and late melt 1867 GLACIER FRAGMENTATION EFFECTS ON SURFACE ENERGY BALANCE AND RUNOFF

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Using Landsat-5 thematic mapper and digital elevation data to determine the net radiation field of a Mountain Glacier

Cited by 65 publications

References 23 publications

Modeling Top of Atmosphere Radiance over Heterogeneous Non-Lambertian Rugged Terrain

Modeling Top of Atmosphere Radiance over Heterogeneous Non-Lambertian Rugged Terrain

Use of remote sensing for hydrological parameterisation of Alpine catchments

Glacier fragmentation effects on surface energy balance and runoff: field measurements and distributed modelling

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