The Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) sensors provide improved signal-to-noise (SNR) radiometric performance quantized over a 12-bit dynamic range.
This translates into 4096 potential grey levels, compared with only 256 grey levels in previous 8-bit instruments. Improved signal to noise performance enables improved characterization of land cover state and condition.
The 12-bit data are scaled to 16-bit integers and delivered in the Level-1 data products. Products are scaled to 55,000 grey levels, and can be rescaled to the Top of Atmosphere (TOA) reflectance and/or radiance using radiometric rescaling coefficients provided in the product metadata file (MTL file).
Visit the Landsat 8 Data Users Handbook for more information.