The SIFSAP (Single Field-of-View Sounder Atmospheric Products) algorithm provides retrieval for each sounder Field of View (FOV), therefore, it has 3-times higher horizontal spatial resolution and 9-time denser products compared to other current IR sounder products. Since SiFSAP is an FOV-based algorithm, its product variables have an additional dimension which represents the number of FOVs. For CrIS instrument, there are 9 FOVs for each Field of Regard (FOR). The SiFSAP L3 products contain a variety of geophysical parameters retrieved from IR/MW sounder suites measurements, including atmospheric temperature profiles, water vapor, ozone profiles, clouds, and surface properties.

This daily one half degree latitude by one half degree longitude level-3 product starts with level-2 retrieval products with QC values of 0 (best), 1 (good), and 2 (don't use). The Level-3 products maximize the yield of each individual variable and level by collecting all cases where the corresponding Level 2 quality control from the top of the atmosphere down to the level where the QC determines that the value is 0 (best) or 1 (good). Below this level, the data is rejected. This gives the greatest possible yield for any given level and variable.