Adding the SOI to the analysis
The 100 year simulations stored in Whopper Cropper can be analysed directly or in groups of analogue years defined by phases of the Southern Oscillation Index (SOI). To enable the SOI phase

1. Open the [Options] menu and select [SOI],
   …or click on the icon on the toolbar.
2. Select the SOI phase for two month period ending in the month selected. For example, November in the SOI phase month selection dialogue box chooses the October–November phase.