Dear users, In the Kaufman-Tanre Aerosol Retrieval tab, set the Maximum Upper Channel Reflectance and the Reflectance Ratio values. These settings identify dark pixels used for the visibility estimate. Recommended values are assigned automatically by choosing one of the options under the Defaults drop-down list. Here are some further tips for setting these values: Only define channels for the processing that is being requested. For example, if you are requesting an aerosol retrieval but not water retrieval, then you can leave the water channels undefined while defining both the KT Upper and KT Lower channels. If you are using the Over-Water Retrieval default settings, the KT Upper and Lower bands are reversed. This is done by design. Applying a maximum reflectance threshold to the 880 nm band tends to better discriminate clear water from turbid or wet areas, leading to more accurate visibility retrievals. (http://www.exelisvis.com/...LAASH.html#Select7). i am working on LANDSAT 8 to map the flooded area. I selected the above parameters. Am i selecting the appropriate method to retrieve water pixels?? I need your suggestions. Thanx in advance.