The development and validation of an "in-situ" correction algorithm for Rotating Shadowband Irradiometers has been done. This algorithm is based on the use of simultaneous measurements from a RSI & thermal-pyranometer setup to dynamically take into account the local atmospheric conditions of the measurement site. This correction is based on a data buffer containing the simultaneous thermal and RSI measurements from a fixed number of past days. This buffer is used to dynamically optimize the GHI functional corrections. For comparison, 3 different DHI corrections have been developed to be used in the dynamic algorithm. These functions are based on the already corrected GHI, a spectral parameter, absolute air mass and solar zenith angle. For validation, the comparison between the performances of the new dynamic algorithm using the different diffuse corrections and the performances obtained with the established correction algorithms has been made. Due to the dynamic behavior of the improved correction algorithm no long-term RSI calibration factors are needed to achieve performances comparable to the established algorithms. [ABSTRACT FROM AUTHOR]