Abstract. It is assumed that external forcing synchronizes processes initiated by it. The concept of the synchronicity of processes is defined, based on their essential signs. The processes under study are decomposed on latent orthogonal components, which differ because of the coincidence and non-coincidence of the essential signs. The information from the original data is redistributed without distortion between these components. For computation of the components, algorithms were developed, using the Fourier transform on the basis of trigonometric functions. Theory and algorithms were applied to decompose on the components the Wolf numbers and the temperature series at 818 weather stations of the Northern Hemisphere from 1955 to 2010. By this approach, new properties of solar–terrestrial relations were revealed; the method characterizes the manifestation of the forcing and corresponds to the well-known notions of climatic processes. Therefore, the new method is informative, consistent; and it is suitable for the analysis of series under observation at this time.