## 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)

## SEE ALSO

r.sun, i.vi

## AUTHOR

Yann Chemin

## SOURCE CODE

Available at: i.albedo source code (history)

Accessed: Sat Nov 12 22:10:51 2022

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