This training material is part of the 2nd GHRSST short course on SST, which took place at the Ocean University of China from 31 May to 2 June 2017. The short course consists of seven sessions with the overall objectives to: To gain knowledge about GHRSST and what GHRSST provides To gain knowledge of IR radiative transfer, cloud masking and SST retrieval To apply the gained knowledge with real practical examples The Key SST Retrieval Concepts session outlines: Cloud screening Multi-channel atmospheric correction algorithms SST retrieval using radiative transfer simulations