Copyright 2013 The Yale Center for Earth Observation http://www.yale.edu/ceo 1

Converting Landsat Digital Numbers to Albedo

Albedo is an important property of the Earth surface heat budget. A simple definition of albedo (a) is the average

reflectance of the suns spectrum. This unitless quantity has values ranging from 0 to 1.0 and will vary based on

the land cover. For example snow would have a high value and coniferous forests a low value.

The input to the albedo calculation will be a Landsat image that has been converted from digital numbers to Top

of Atmosphere (TOA) reflectance. Please refer to the FAQ Converting Digital Numbers to Top of Atmosphere

Reflectance on this site for detailed instructions on how to accomplish this.

Liang (2000) developed a series of algorithms for calculating albedo from various satellite sensors. His Landsat

formula to calculate Landsat shortwave albedo was normalized by Smith (2010) and is presented below.

5 71 3 40.356 0.130 0.373 0.085 0.072 0.0018

0.356 0.130 0.373 0.085 0.072short

Where represents Landsat bands 1,3,4,5, and 7. Note that Landsat band 2 (green) is not used.

This formula can be implemented in ENVI using Band Math as:

((0.356*B1) + (0.130*B2) + (0.373*B3) + (0.085*B4) + (0.072*B5) -0.018) / 1.016

Note: If you have areas outside of the image scene or mask area with values of 0.0 these will have a negative

value. You should apply a mask to convert these fill values to NaN (Not a Number) before or after calculating

albedo.

References Liang, S. 2000. Narrowband to broadband conversions of land surface albedo I algorithms. Remote Sensing of

Environment 76, 213-238.

Smith, R.B. 2010. The heat budget of the earths surface deduced from space available on

http://www.yale.edu/ceo/Documentation/ceo_faq.html