Validation of an empirical method for thin cirrus correction with Sentinel-2 data

摘要

Semi-transparent clouds, the so-called cirrus, frequently contaminate satellite images. Recently, Gao and Li (2017)have developed an empirical method for thin cirrus correction with focus on data provided by Landsat-8. This correctionallows one to estimate clear-sky apparent reflectance. Validated qualitatively, we propose here a quantitative validationmethod using Sentinel-2 data by comparing the corrected image with a clear sky reference image. Their method showsgood results on dark surfaces, like water, with an apparent reflectance found close to 0.02. On the other hand, it becomesless accurate for thicker cirrus and on more reflective surfaces. In addition, the data analysis shows that pixels located inthe shadow of the cirrus are over-corrected. The downward path should therefore be taken into account when correctingthe signal.