Landsat 8-9 Surface Reflectance Quality Assessment

By Landsat Missions

Landsat 8 and Landsat 9 Collection 2 Surface Reflectance products are consistent, science-quality data and are atmospherically corrected for accurate analysis of land surface changes over time. Quality Assessment bands included with the products provide bit-packed combinations of surface, atmosphere, and sensor conditions that can affect the overall usefulness of a given pixel.

Return to Landsat Surface Reflectance Quality Assessment Overview

Landsat 8-9 Surface Reflectance Science Products are generated from Landsat Surface Reflectance Code (LaSRC) specialized software. During Landsat 8-9 OLI/TIRS Surface Reflectance generation, LaSRC assesses the following quality conditions and expresses them using the bands described below.

Specific attributes for each band described below are available in the Landsat 8-9 Collection 2 Level-2 Science Product Guide.

SR_QA_AEROSOL band

LaSRC quality conditions are expressed as a confidence level or as either true or false.

Fill – There are no data values in this pixel.
Aerosol Retrieval – The retrieval of aerosol measurements was valid in this pixel.

Water – LaSRC identified this pixel as water.

Cloud or Cirrus - LaSRC identified this pixel as cloud or cirrus cloud.

Cloud shadow - LaSRC identified this pixel as cloud shadow.

Aerosol Retrieval - The retrieval of aerosol measurements was invalid and interpolated from nearby observations.

Aerosol Content – LaSRC determined the amount of aerosol in this pixel to be climatology-grade, low, medium, or high.

QA_PIXEL band

The Pixel QA band is generated by the C Function of Mask (CFMask) algorithm and can be used as an alternative quality assessment source for pixel quality. The band is carried through unchanged from Landsat Level-1 data and contains cloud, cloud confidence, cloud shadow, snow/ice and water information. Note: this band is likely to present more accurate results than the internal tests LaSRC uses for cloud, cloud shadow, snow/ice and water. The Pixel QA band’s quality conditions are expressed as a confidence level or as either true or false.

QA_RADSAT band

The Radiometric Saturation band's quality conditions are expressed as either true or false and are stored in the QA_RADSAT bit-packed file. This band is a representation of which sensor bands were saturated during data capture, yielding unusable data.