The Interactive Double Mass Analysis (IDMA) display is used for seeing differences between accumulations of observation data for a specific (target) location and average accumulation of observation data from a base group of locations. The target location can be selected from a drop down on the display, as shown in the screenshot below. In this case, CHEPACHET is selected, which is why the blue line is thicker than the rest. If observation data is not available, estimated data is used, which is shown by a thin gray line.
If accumulation differences do not seem to follow a sensible trend, it is possible to apply a modifier for the period where the trend needs to be corrected. To do so, start and end times need to be selected via the date pickers from the top panel. There are two orange markers on the display which correspond to the selected times. It is also possible to define a multiplication factor, which is 2 in the example below. Then a modifier can be created based on the selected period and multiplication factor.
In addition, it is possible to see raw estimates as dashed lines for locations to which a modifier was applied. This helps comparing the original accumulations differences of the estimated data with the modified accumulations differences.
Further details about the IDMA display and configuration for it are described in detail on this page.