Page 1 of 1

LANCE: What is the difference between Corrected Reflectance vs. Surface Reflectance Imagery?

Posted: Thu Feb 15, 2024 1:20 pm America/New_York
by Earthdata - wxedward
For both MODIS and VIIRS, the Corrected Reflectance algorithm utilizes Level 1B data (the calibrated, geolocated radiances). It is not a standard, science quality product and is available only as near real-time imagery. The imagery can be visualized in Worldview and GIBS.

For MODIS, the sensor resolution is 500 m and 250 m (Bands 1 and 2 have a sensor resolution of 250 m, Bands 3 – 7 have a sensor resolution of 500m, and Bands 8 - 36 are 1 km. Band 1 is used to sharpen Band 3, 4, 6, and 7), imagery resolution is 250 m, and the temporal resolution is daily.The purpose of this algorithm is to provide natural-looking images by removing gross atmospheric effects, such as Rayleigh scattering, from MODIS visible bands 1-7. The algorithm was developed by the original MODIS Rapid Response team to address the needs of the fire monitoring community who want to see smoke. Corrected Reflectance shows smoke more clearly than the standard Surface Reflectance product. In contrast, the MODIS Land Surface Reflectance product (MOD09) is a more complete atmospheric correction algorithm that includes aerosol correction, and is designed to derive land surface properties. In clear atmospheric conditions, the Corrected Reflectance product is very similar to the MOD09 product, but they depart from each other in presence of aerosols. If you wish to perform a complete atmospheric correction, please do not use the Corrected Reflectance algorithm. An additional difference is that the Land Surface Reflectance product is only tuned for calculating the reflectance over land surfaces.

The VIIRS Corrected Reflectance imagery provides continuity from the MODIS Corrected Reflectance imagery and was developed to provide natural-looking images by removing gross atmospheric effects such as Rayleigh scattering from the visible bands. By contrast, the Surface Reflectance product is available in near real-time and as a standard product. Surface Reflectance provides a more complete atmospheric correction algorithm that includes aerosol correction and is designed to derive land surface properties. In clear atmospheric conditions the corrected reflectance product is similar to the Surface Reflectance product but they depart from each other in the presence of aerosols.