The built-in library of the International Geosphere Biosphere Programme is selected with
albedo_library IGBPThe IGBP library contains 20 surface types which are set by surface_type:
1 evergreen_needle_forest 2 evergreen_broad_forest 3 deciduous_needle_forest 4 deciduous_broad_forest 5 mixed_forest 6 closed_shrubs 7 open_shrubs 8 woody_savanna 9 savanna 10 grassland 11 wetland 12 cropland 13 urban 14 crop_mosaic 15 antarctic_snow 16 desert 17 ocean_water 18 tundra 19 fresh_snow 20 sea_iceSurface types 1 - 17 are defined by the International Geosphere Biosphere Programme (IGBP); additionally there are tundra, fresh_snow, and sea_ice surface types. The spectral albedo of the ground is determined as a function of solar zenith angle, precitable water, and clouds. The spectral resolution equals the grid of the correlated-k Fu/Liou parameterisation. This library originates from the NASA CERES/SARB Surface Properties Project, see Belward and Loveland (1996).
For creating your own albedo library use albedo_library path, where path is the path of the directory where the albedo data is stored. The files are expected to have the names albedo_01.dat, albedo_02.dat, ... If surface_type 1 is specified the albedo from albedo_01.dat will be used, and so on. Each file is required to have two columns: Column 1 is the wavelength in nm, and column 2 the corresponding Lambertian surface albedo. The wavelength grid may be freely set. The albedo will be interpolated linearely to the wavelength grid used for the radiation calculation. Comments start with #. Empty lines are ignored. This option is similar to albedo_file, except that it offers an easy way to use the option surface_type_map in combinition with albedo files.