Removal of Thin Clouds Using Cirrus and QA Bands of Landsat-8

After atmospheric correction, an algorithm for the removal of thin cirrus cloud as well as alto-thin clouds or thin clouds collectively within visible and near infrared bands (Bands 1 through 5) of Landsat-8 was developed. The algorithm removed cirrus clouds using Band 9 first, and the remaining thin clouds using quality assurance (QA) band. Using a Landsat-8 sub-image of 129/39 (path/row) acquired on 16 December 2013, we evaluated the algorithm. Thin clouds disappeared visually. Reflectance values of Bands 1 through 4 decreased in both steps. Reflectance values of Band 5 decreased in step one, and then stayed the same. With a nearly cloud-free image acquired on 30 November 2013 as the "truth," the spatial correlation coefficients of cloud-covered pixels within the December image were 0.84 or higher. Changes in reflectance values of Bands 1 to 5, and the high correlation coefficient values indicated the validity of the algorithm.