Hemispherical-Directional Reflectance (HDRF) of Windblown Snow-Covered Arctic Tundra at Large Solar Zenith Angles

Ground-based measurements of the hemispherical directional reflectance factor (HDRF) of windblown snow covered Arctic tundra were measured at large solar zenith angles (79°-85°) for six sites near the international research base in Ny-Ålesund, Svalbard. Measurements were made with the Gonio RAdiometric Spectrometer System over the viewing angles 0°-50° and the azimuth angles 0°-360°, for the wavelength range 400-1700 nm. The HDRF measurements showed good consistency between sites for near-nadir and backward viewing angles, with a relative standard deviation of less than 10% between sites where the snowpack was smooth and the snow depth was greater than 40 cm. The averaged HDRF showed good symmetry with respect to the solar principal plane and exhibited a forward scattering peak that was strongly wavelength dependent, with greater than a factor of 2 increase in the ratio of maximum to minimum HDRF values for all viewing angles over the wavelength range 400-1300 nm. The angular effects on the HDRF had minimal influence for viewing angles less than 150 in the backward viewing direction for the averaged sites and agreed well with another study of snow HDRF for infrared wavelengths, but showed differences of up to 0.24 in the HDRF for visible wavelengths owing to light-absorbing impurities measured in the snowpack. The site that had the largest roughness elements showed the strongest anisotropy in the HDRF, a large reduction in forward scattering, and a strong asymmetry with respect to the solar principal plane.

[1]  Ice.  The international classification for seasonal snow on the ground , 1990 .

[2]  Nigel P. Fox,et al.  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 , 2015 .

[3]  F. Clarke,et al.  Helmholtz Reciprocity: its validity and application to reflectometry , 1985 .

[4]  A. MacArthur,et al.  Calculations of in‐snow NO2 and OH radical photochemical production and photolysis rates: A field and radiative‐transfer study of the optical properties of Arctic (Ny‐Ålesund, Svalbard) snow , 2011 .

[5]  Alexei Lyapustin,et al.  A new method of retrieving surface bidirectional reflectance from ground measurements: Atmospheric sensitivity study , 1999 .

[6]  M. Kuhn.  Bidirectional Reflectance of Polar and Alpine Snow Surfaces , 1985 .

[7]  David C. Williams.  Establishment of absolute diffuse reflectance scales using the NPL Reference Reflectometer , 1999 .

[8]  S. Warren,et al.  A Model for the Spectral Albedo of Snow. I: Pure Snow , 1980 .

[9]  S. Warren.  Can black carbon in snow be detected by remote sensing? , 2013 .

[10]  Nigel P. Fox,et al.  Progress in Field Spectroscopy , 2006, 2006 IEEE International Symposium on Geoscience and Remote Sensing.

[11]  S. Warren,et al.  Light absorption from particulate impurities in snow and ice determined by spectrophotometric analysis of filters. , 2011, Applied Optics.

[12]  Stephen G. Warren,et al.  Optical Properties of Snow , 1982 .

[13]  Yanmin Shuai,et al.  Validation of Moderate Resolution Imaging Spectroradiometer (MODIS) albedo retrieval algorithm: Dependence of albedo on solar zenith angle , 2009 .

[14]  J. Muller,et al.  MODIS BRDF / Albedo Product : Algorithm Theoretical Basis Document Version 5 . 0 , 1999 .

[15]  Jukka Piironen,et al.  Measurement of directional and spectral signatures of light reflectance by snow , 2005, IEEE Transactions on Geoscience and Remote Sensing.

[16]  Yann Kerr,et al.  Bidirectional reflectance of a rough anisotropic surface , 2002 .

[17]  S. Warren,et al.  Reflection of solar radiation by the Antarctic snow surface at ultraviolet, visible, and near‐infrared wavelengths , 1994 .

[18]  M. Fily,et al.  Modeling the effect of sastrugi on snow reflectance , 1998 .

[19]  Stephen G. Warren,et al.  Effect of surface roughness on bidirectional reflectance of Antarctic snow , 1998 .

[20]  T. Painter,et al.  Reflectance quantities in optical remote sensing - definitions and case studies , 2006 .

[21]  Antony D. Clarke,et al.  Light-absorbing impurities in Arctic snow , 2010 .

[22]  Thomas H. Painter,et al.  Retrieval of subpixel snow covered area, grain size, and albedo from MODIS , 2009 .

[23]  H. Iwabuchi,et al.  Effect of sastrugi on snow bidirectional reflectance and its application to MODIS data , 2011 .

[24]  F. Mims,et al.  Design, calibration, and performance of MICROTOPS II handheld ozone monitor and Sun photometer , 2001 .

[25]  R. Armstrong,et al.  The international classification for seasonal snow on the ground (UNESCO, IHP (International Hydrological Programme)–VII, Technical Documents in Hydrology, No 83; IACS (International Association of Cryospheric Sciences) contribution No 1) , 2009 .

[26]  F. E. Nicodemus,et al.  Geometrical considerations and nomenclature for reflectance , 1977 .

[27]  X. Qu,et al.  Surface Contribution to Planetary Albedo Variability in Cryosphere Regions , 2005 .

[28]  A. Ohmura,et al.  A field study of the hemispherical directional reflectance factor and spectral albedo of dry snow , 2006 .

[29]  Crystal B. Schaaf,et al.  Accuracy assessment of the MODIS 16-day albedo product for snow: comparisons with Greenland in situ measurements , 2005 .

[30]  N. C. Strugnell,et al.  First operational BRDF, albedo nadir reflectance products from MODIS , 2002 .

[31]  A. MacArthur,et al.  Hydroxyl radical and NOx production rates, black carbon concentrations and light‐absorbing impurities in snow from field measurements of light penetration and nadir reflectivity of onshore and offshore coastal Alaskan snow , 2012 .

[32]  T. Painter,et al.  Measurements of the hemispherical-directional reflectance of snow at fine spectral and angular resolution , 2004 .

[33]  Andrew Deadman,et al.  NPL scales for radiance factor and total diffuse reflectance , 2003 .

[34]  Dorothy K. Hall,et al.  Reflectance of snow measured in situ and from space in sub-Arctic areas in Canada and Alaska , 1992, IEEE Trans. Geosci. Remote. Sens..

[35]  Donald K. Perovich,et al.  Radiative forcing and albedo feedback from the Northern Hemisphere cryosphere between 1979 and 2008 , 2011 .

[36]  Lukas Furst.  Computational Geometry Algorithms And Applications , 2016 .

[37]  J. J. Simpson,et al.  Anisotropic Reflectance of Snow Observed from Space over the Arctic and Its Effect on Solar Energy Balance , 2001 .

[38]  N. Fox,et al.  Effect of polytetrafluoroethylene (PTFE) phase transition at 19°C on the use of Spectralon as a reference standard for reflectance. , 2013, Applied optics.

[39]  The NPL Gonio RAdiometric Spectrometer System (GRASS) , 2008 .

[40]  S. Warren,et al.  Spectral Bidirectional Reflectance of Antarctic Snow: Measurements and Parameterization , 2006 .

[41]  Alan H. Strahler,et al.  MODIS BRDF/Albedo Product: Algorithm Theoretical Bais Document v3.2 , 1995 .

[42]  M. Chapman,et al.  Design and Testing a New Instrument to Measure the Angular Reflectance of Terrestrial Surfaces , 2006, 2006 IEEE International Symposium on Geoscience and Remote Sensing.

[43]  S. Sandmeier,et al.  Sensitivity analysis and quality assessment of laboratory BRDF data , 1998 .

[44]  M. S. Moran,et al.  Bidirectional Calibration Results for 11 Spectralon and 16 BaSO4 Reference Reflectance Panels , 1992 .