Hi,
I need some suggestions to run r.sun and use the Albedo-Modis product as an input for the r.sun albedo parameter.
Albedo-Modis has two main products: White-sky and Black-sky
"White-sky is the bihemispherical reflectance under conditions of isotropic illumination, so it has the angular dependency removed. Black-sky is the directional hemispherical reflectance computed at local solar noon."
Which one of these is the most appropriate to use?
Moreover, “white-sky” and “black-sky” are computed at 10 wavelengths (0.47µm, 0.55µm, 0.67µm, 0.86µm, 1.24µm, 2.1µm, 0.3-0.7µm, 0.3-5.0µm, and 0.7-5.0µm).
Which one is the most appropriate to use?
The only info that i found for this is
i.albedo calculates the Albedo, that is the Shortwave surface reflectance in the range of 0.3-3 micro-meters. It takes input of individual bands of surface reflectance from Modis, AVHRR, Landsat or Aster and calculates the Albedo for those. This is an precursor to r.sun and any Energy-Balance processing.
so the 0.3-5.0µm should be the more suitable for this purpose. Correct?
My final aim is to use ancillary layers to “fill” all the different parameters of r.sun.
All the examples that i found use constant or default values.
May anyone point to me some source of information?
Thanks in Advance
–
Giuseppe Amatulli, Ph.D.
Center for Earth Observation
ESC Room 119A
Yale University
P.O. Box 208109
New Haven, CT, 06520-8109
Teaching: spatial-ecology.net
Work: http://sbsc.yale.edu/training-and-support