NAME

i.albedo - Computes broad band albedo from surface reflectance.

KEYWORDS

imagery, albedo, reflectance, satellite, Landsat, ASTER, AVHRR, MODIS

SYNOPSIS

i.albedo
i.albedo --help
i.albedo [-mnl8acd] input=name[,name,...] output=name [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-m: MODIS (7 input bands:1,2,3,4,5,6,7)
-n: NOAA AVHRR (2 input bands:1,2)
-l: Landsat 5+7 (6 input bands:1,2,3,4,5,7)
-8: Landsat 8 (7 input bands:1,2,3,4,5,6,7)
-a: ASTER (6 input bands:1,3,5,6,8,9)
-c: Aggressive mode (Landsat)
Albedo dry run to calculate some water to beach/sand/desert stretching, a kind of simple atmospheric correction
-d: Soft mode (MODIS)
Albedo dry run to calculate some water to beach/sand/desert stretching, a kind of simple atmospheric correction
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

input=name[,name,...] [required]: Name of input raster map
output=name [required]: Name for output raster map

DESCRIPTION

i.albedo calculates the albedo, that is the Shortwave surface reflectance in the range of 0.3-3 micro-meters. It takes as input individual bands of surface reflectance originating from MODIS, AVHRR, Landsat or Aster satellite sensors and calculates the albedo for those. This is a precursor to r.sun and any energy-balance processing.

NOTES

It uses for Landsat 8 the weighted average reflectance (temporary solution until an algorithm is found).

It assumes MODIS product surface reflectance in [0;10000].

EXAMPLE

The following example creates the raster map "albedo_lsat7_1987" from the LANDSAT-TM5 bands in the North Carolina dataset:

g.region raster=lsat5_1987_10 -p
i.albedo -l input=lsat5_1987_10,lsat5_1987_20,lsat5_1987_30,lsat5_1987_40,lsat5_1987_50,lsat5_1987_70 output=albedo_lsat7_1987

Figure: Resulting albedo map from LANDSAT 5

The following example creates the raster map "albedo_lsat7_2000" from the LANDSAT-TM7 bands in the North Carolina dataset:

g.region raster=lsat7_2000_10 -p
i.albedo -l input=lsat7_2000_10,lsat7_2000_20,lsat7_2000_30,lsat7_2000_40,lsat7_2000_50,lsat7_2000_70 output=albedo_lsat7_2000

Figure: Resulting albedo map from LANDSAT 7

TODO

Maybe change input requirement of MODIS to [0.0-1.0]?

REFERENCES

For a 2 band determination of the Aster BB Albedo see the following:

Salleh and Chan, 2014. Land Surface Albedo Determination: Remote Sensing and Statistical Validation. in proceedings of FIG 2014 (PDF)

AUTHOR

Yann Chemin

SOURCE CODE

Available at: i.albedo source code (history)

Latest change: Wednesday Nov 06 09:48:42 2024 in commit: 3fce7972a6d3b502e8471bd440cca2aacedbc748