The surface reflectance, i.e., satellite derived top of atmosphere (TOA) reflectance
corrected for the temporally, spatially and spectrally varying scattering and absorbing
effects of atmospheric gases and aerosols, is needed to monitor the land surface reliably.
For this reason, the surface reflectance, and not TOA reflectance, is used to generate
the greater majority of global land products, for example, from the Moderate Resolution
Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS)
sensors. Even if atmospheric effects are minimized by sensor design, atmospheric effects
are still challenging to correct. In particular, the strong impact of aerosols in
the Visible and Near Infrared spectral range can be difficult to correct, because
they can be highly discrete in space and time (e.g., smoke plumes) and because of
the complex scattering and absorbing properties of aerosols that vary spectrally and
with aerosol size, shape, chemistry and density. This paper presents the Landsat 8
Operational Land Imager (OLI) atmospheric correction algorithm that has been developed
using the Second Simulation of the Satellite Signal in the Solar Spectrum Vectorial
(6SV) model, refined to take advantage of the narrow OLI spectral bands (compared
to Thematic Mapper/Enhanced Thematic Mapper (TM/ETM+)), improved radiometric resolution
and signal-to-noise. In addition, the algorithm uses the new OLI Coastal aerosol band
(0.433–0.450μm), which is particularly helpful for retrieving aerosol properties,
as it covers shorter wavelengths than the conventional Landsat, TM and ETM+ blue bands.
A cloud and cloud shadow mask has also been developed using the “cirrus” band (1.360–1.390
μm) available on OLI, and the thermal infrared bands from the Thermal Infrared Sensor
(TIRS) instrument. The performance of the surface reflectance product from OLI is
analyzed over the Aerosol Robotic Network (AERONET) sites using accurate atmospheric
correction (based on in situ measurements of the atmospheric properties), by comparison
with the MODIS Bidirectional Reflectance Distribution Function (BRDF) adjusted surface
reflectance product and by comparison of OLI derived broadband albedo from United
States Surface Radiation Budget Network (US SURFRAD) measurements.