Hemispherical reflectance and albedo estimates from the accumulation of across‐track sun‐synchronous satellite data

The estimation of the hemispherical reflectance and the instantaneous albedo of canopies from top of canopy satellite reflectance data was investigated. The study was designed to approximate the specifications of generic sensors aboard satellites like NOAA, VEGETATION, MERIS, MISR, MODIS, and PRISM. These sensors acquire reflectance data in two to six wave bands distributed along the visible, near-infrared, and middle infrared domains. Five great biomes (grassland, sparse vegetation, tropical forest, boreal forest, and bare soil) were approximated, simulating the corresponding top of canopy reflectances as observed from the satellites using well-known leaf, soil, and canopy radiative transfer models, including the effect of cloud cover that limits the actual data acquisition scheme. Albedo was accurately derived from the hemispherical reflectance observed in only a few wave bands. When using six wave bands, albedo was estimated within 1% relative accuracy. The MRPV bidirectional reflectance distribution function (BRDF) model was tested to derive the hemispherical reflectance from the top of canopy bidirectional data as sampled by the generic sensors during a 32 day orbit cycle. Results showed that this is the main source of error, with a relative accuracy around 6%. This showed the importance of the directional sampling scheme and possible improvements that may be made to the model and the way it is fitted to the observed data. The algorithm developed produced a relative accuracy less than 7% for the albedo estimation, when using the six wave bands and a ±45° across-track directional scanning capacity. The results were discussed with particular emphasis on the optimization of sensors and algorithms dedicated to albedo estimation and to the use of hemispherical reflectance as a potential normalized geophysical product for monitoring vegetation.

[1]  Bernard Pinty,et al.  Parametric surface bidirectional reflectance factor models for atmospheric radiative transfer modeling , 1998, IGARSS '98. Sensing and Managing the Environment. 1998 IEEE International Geoscience and Remote Sensing. Symposium Proceedings. (Cat. No.98CH36174).

[2]  H. Rahman,et al.  Coupled surface-atmosphere reflectance (CSAR) model: 2. Semiempirical surface model usable with NOAA advanced very high resolution radiometer data , 1993 .

[3]  W. Lucht.  Expected retrieval accuracies of bidirectional reflectance and albedo from EOS-MODIS and MISR angular sampling , 1998 .

[4]  P. Deschamps,et al.  Description of a computer code to simulate the satellite signal in the solar spectrum : the 5S code , 1990 .

[5]  Michael Rast,et al.  PRISM: a hyperspectral imager for a future ESA land observation mission , 1995, Remote Sensing.

[6]  Ranga B. Myneni,et al.  Photon-Vegetation Interactions , 1991, Springer Berlin Heidelberg.

[7]  R. Dickinson,et al.  A physical model of the bidirectional reflectance of vegetation canopies: 2. Inversion and validation , 1990 .

[8]  B. Pinty,et al.  On the design and validation of surface bidirectional reflectance and albedo models , 1992 .

[9]  R. Myneni,et al.  A Three-Dimensional Radiative Transfer Method for Optical Remote Sensing of Vegetated Land Surfaces , 1991, [Proceedings] IGARSS'91 Remote Sensing: Global Monitoring for Earth Management.

[10]  J. Privette,et al.  Estimating spectral albedo and nadir reflectance through inversion of simple BRDF models with AVHRR/MODIS‐like data , 1997 .

[11]  Y. Knyazikhin,et al.  Discrete Ordinates Method for Photon Transport in Leaf Canopies , 1991 .

[12]  Ann Henderson-Sellers,et al.  Surface albedo data for climatic modeling , 1983 .

[13]  Tsuyoshi Akiyama,et al.  A portable field ultrasonic sensor for crop canopy characterization , 1985 .

[14]  J.-P. Goutorbe,et al.  HAPEX-Sahel: a large-scale study of land-atmosphere interactions in the semi-arid tropics , 1994 .

[15]  B. Pinty,et al.  A physical model of the bidirectional reflectance of vegetation canopies , 1990 .

[16]  Bernard Pinty,et al.  Multi-angle Imaging SpectroRadiometer (MISR) instrument description and experiment overview , 1998, IEEE Trans. Geosci. Remote. Sens..

[17]  R. Dickinson.  Land Surface Processes and Climate—Surface Albedos and Energy Balance , 1983 .

[18]  A. Strahler,et al.  On the derivation of kernels for kernel‐driven models of bidirectional reflectance , 1995 .

[19]  B. Hapke.  Bidirectional reflectance spectroscopy: 1. Theory , 1981 .

[20]  F. Baret,et al.  PROSPECT: A model of leaf optical properties spectra , 1990 .

[21]  J. C. Price.  On the information content of soil reflectance spectra , 1990 .

[22]  G. Campbell,et al.  Simple equation to approximate the bidirectional reflectance from vegetative canopies and bare soil surfaces. , 1985, Applied optics.

[23]  D. S. Kimes,et al.  Hemispherical Reflectance Variations of Vegetation Canopies and Implications for Global and Regional Energy Budget Studies , 1987 .

[24]  Piers J. Sellers,et al.  Inferring hemispherical reflectance of the earth's surface for global energy budgets from remotely sensed nadir or directional radiance values , 1985 .

[25]  Jean-Pierre Wigneron,et al.  Estimation of Evapotranspiration and Photosynthesis by Assimilation of Remote Sensing Data into SVAT Models , 1999 .

[26]  F. Baret,et al.  Modeling Spectral and Bidirectional Soil Reflectance , 1992 .

[27]  B. Pinty,et al.  A simple bidirectional reflectance model for terrestrial surfaces , 1986 .

[28]  B. Hapke.  Bidirectional reflectance spectroscopy: 4. The extinction coefficient and the opposition effect , 1986 .

[29]  C. L. Wiegand,et al.  View azimuth and zenith, and solar angle effects on wheat canopy reflectance , 1985 .

[30]  Michael J. Barnsley,et al.  Global retrieval of bidirectional reflectance and albedo over land , 1997 .

[31]  A. Kuusk,et al.  A reflectance model for the homogeneous plant canopy and its inversion , 1989 .

[32]  J. Roujean,et al.  A bidirectional reflectance model of the Earth's surface for the correction of remote sensing data , 1992 .

[33]  B. Hapke.  Bidirectional reflectance spectroscopy , 1984 .

[34]  Annick Bricaud,et al.  The POLDER mission: instrument characteristics and scientific objectives , 1994, IEEE Trans. Geosci. Remote. Sens..