Demonstration of iterative DSS in the experiment with extracting El Niño index

In this experiment, the iterative DSS procedure is based on band-pass filtering which emphasizes interannual events. The algorithm is applied to global surface temperature data and it extracts El Niño index as the signal with the most prominent interannual variability.

The black curve on the upper plot is the estimate of the time signal and the red curve is the same signal after filtering. The map below indicates the regions in which the effect of the corresponding phenomenon is largest. The slide show presents how the solution changes during the iterative procedure. You can also run the iterations step by step using the links below the figure.