Characterisation of the HDRF (as a proxy for BRDF) of snow surfaces at Dome C, Antarctica, for the inter-calibration and inter-comparison of satellite optical data

Marks, A. A.; Fragiacomo, C.; MacArthur, Alasdair; Zibordi, Giuseppe; Fox, Nigel; King, Martin D.

doi:10.1016/j.rse.2014.11.013

Cited by 19 publications

(8 citation statements)

References 38 publications

(80 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the drawback of the rather simple computations is their restricted accuracy. Semi-empirical models (e.g., Martonchik et al, 1998; use simple, direct parameterizations of a more complex physical BRDF with a limited number of independent parameters.…”

Section: Introductionmentioning

confidence: 99%

Parameterizing anisotropic reflectance of snow surfaces from airborne digital camera observations in Antarctica

et al. 2020

View full text Add to dashboard Cite

Abstract. The surface reflection of solar radiation comprises an important boundary condition for solar radiative transfer simulations. In polar regions above snow surfaces, the surface reflection is particularly anisotropic due to low Sun elevations and the highly anisotropic scattering phase function of the snow crystals. The characterization of this surface reflection anisotropy is essential for satellite remote sensing over both the Arctic and Antarctica. To quantify the angular snow reflection properties, the hemispherical-directional reflectance factor (HDRF) of snow surfaces was derived from airborne measurements in Antarctica during austral summer in 2013/14. For this purpose, a digital 180∘ fish-eye camera (green channel, 490–585 nm wavelength band) was used. The HDRF was measured for different surface roughness conditions, optical-equivalent snow grain sizes, and solar zenith angles. The airborne observations covered an area of around 1000 km × 1000 km in the vicinity of Kohnen Station (75∘0′ S, 0∘4′ E) at the outer part of the East Antarctic Plateau. The observations include regions with higher (coastal areas) and lower (inner Antarctica) precipitation amounts and frequencies. The digital camera provided upward, angular-dependent radiance measurements from the lower hemisphere. The comparison of the measured HDRF derived for smooth and rough snow surfaces (sastrugi) showed significant differences, which are superimposed on the diurnal cycle. By inverting a semi-empirical kernel-driven bidirectional reflectance distribution function (BRDF) model, the measured HDRF of snow surfaces was parameterized as a function of solar zenith angle, surface roughness, and optical-equivalent snow grain size. This allows a direct comparison of the HDRF measurements with the BRDF derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite product MCD43. For the analyzed cases, MODIS observations (545–565 nm wavelength band) generally underestimated the anisotropy of the surface reflection. The largest deviations were found for the volumetric model weight fvol (average underestimation by a factor of 10). These deviations are likely linked to short-term changes in snow properties.

show abstract

Section: Introductionmentioning

confidence: 99%

Parameterizing anisotropic reflectance of snow surfaces from airborne digital camera observations in Antarctica

et al. 2020

View full text Add to dashboard Cite

show abstract

“…They concluded that wavelength and solar zenith angles were sufficient to accurately parameterize the main features in snow reflectance anisotropy. Snow reflectance anisotropy measured by Hudson et al () were compared with field measurements performed by Marks et al () over the same area but with viewing footprints varying from 0.049 m 2 to 0.142 m 2 . Good agreements were found between the two studies when the small scale measurements made at several sites along a 100 m transect were averaged.…”

Section: Introductionmentioning

confidence: 99%

High Angular Resolution Measurements of the Anisotropy of Reflectance of Sea Ice and Snow

Goyens

Marty

Leymarie

et al. 2018

Earth and Space Science

View full text Add to dashboard Cite

We introduce a new method to determine the anisotropy of reflectance of sea ice and snow at spatial scales from 1 m2 to 80 m2 using a multispectral circular fish‐eye radiance camera (CE600). The CE600 allows measuring radiance simultaneously in all directions of a hemisphere at a 1° angular resolution. The spectral characteristics of the reflectance and its dependency on illumination conditions obtained from the camera are compared to those obtained with a hyperspectral field spectroradiometer manufactured by Analytical Spectral Device, Inc. (ASD). Results confirm the potential of the CE600, with the suggested measurement setup and data processing, to measure commensurable sea ice and snow hemispherical‐directional reflectance factor, HDRF, values. Compared to the ASD, the reflectance anisotropy measured with the CE600 provides much higher resolution in terms of directional reflectance (N = 16,020). The hyperangular resolution allows detecting features that were overlooked using the ASD due to its limited number of measurement angles (N = 25). This data set of HDRF further documents variations in the anisotropy of the reflectance of snow and ice with the geometry of observation and illumination conditions and its spectral and spatial scale dependency. Finally, in order to reproduce the hyperangular CE600 reflectance measurements over the entire 400–900 nm spectral range, a regression‐based method is proposed to combine the ASD and CE600 measurements. Results confirm that both instruments may be used in synergy to construct a hyperangular and hyperspectral snow and ice reflectance anisotropy data set.

show abstract

“…Kuhn (1985) observed a peak in reflectance in the azimuthal directions up to 60 • to both sides of the solar azimuth that becomes more prominent with increasing solar zenith angle and snow grain size. Marks et al (2015) measured the HDRF of snow surfaces between 400 and 1600 nm wavelength with the Gonio Radiometric Spectrometer System (GRASS, Pegrum et al, 2006) at Dome C, Antarctica. Their observations also showed enhanced forward scattering.…”

Section: Introductionmentioning

confidence: 99%

Parameterizing anisotropic reflectance of snow surfaces from airborne digital camera observations in Antarctica

Carlsen¹,

Birnbaum²,

Ehrlich³

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. The angular reflection of solar radiation by snow surfaces comprises an important boundary condition for radiative transfer simulations. In polar regions, the surface reflection is particularly anisotropic due to low sun elevations and the highly anisotropic scattering phase function of ice crystals. This anisotropy needs to be considered in the angular modeling of the surface reflection, which is essential for satellite remote sensing techniques. To quantify the snow reflection properties, the hemispherical-directional reflectance function (HDRF) of snow surfaces was derived from airborne measurements using a digital 180° fish-eye camera (green channel, 490–585 nm wavelength band) in Antarctica during austral summer in 2013/14. This function was measured for different surface roughnesses, optical-equivalent snow grain sizes, and solar zenith angles. The airborne observations covered an area of around 1000 × 1000 km2 in the vicinity of Kohnen station (75°0′ S, 0°4′ E) at the outer part of the East Antarctic Plateau. The observations over Dronning Maud Land include regions with higher (coastal areas) and lower (inner Antarctica) precipitation amounts and frequencies. The digital camera was calibrated in terms of spectral radiances and installed in a downward-looking configuration on a research aircraft. It provides upward, angular-dependent radiance measurements from the lower hemisphere. The comparison of HDRF data derived for smooth and rough snow surfaces (sastrugi) showed significant differences, which are superimposed on the diurnal cycle. By inverting a semi-empirical, kernel-driven bidirectional reflectance distribution function (BRDF) model, the measured HDRF of snow surfaces was parameterized with respect to solar zenith angle, surface roughness, and optical-equivalent snow grain size. This allows a direct comparison of the HDRF measurements with the BRDF derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite product MCD43. For the analyzed cases, MODIS observations generally underestimated the anisotropy of the surface reflection. Some of these deviations between airborne and MODIS satellite retrievals are likely linked to short-term changes in snow properties.

show abstract

Characterisation of the HDRF (as a proxy for BRDF) of snow surfaces at Dome C, Antarctica, for the inter-calibration and inter-comparison of satellite optical data

Cited by 19 publications

References 38 publications

Parameterizing anisotropic reflectance of snow surfaces from airborne digital camera observations in Antarctica

Parameterizing anisotropic reflectance of snow surfaces from airborne digital camera observations in Antarctica

High Angular Resolution Measurements of the Anisotropy of Reflectance of Sea Ice and Snow

Parameterizing anisotropic reflectance of snow surfaces from airborne digital camera observations in Antarctica

Contact Info

Product

Resources

About