Vaisala IRIS - Figure 52 Background Field for 2-Hour Dwell Showing Dbz

Figure 52 Background Field for 2-Hour Dwell Showing dBZ
The smoothed background field has generally lower echo intensity as a result of the
smoothing process. Note that there are no "speckles", that is, only large scale echo features
remain. Thus the background field is a representation of the average background echoes.
When this is subtracted from the input products and thresholded (in applying the contrast
filter), the background echoes are removed, leaving only the high intensity cores or point
targets such as birds or aircraft.
Diagnostic Output for Algorithm Verification
To assist with tuning the DWELL algorithm, especially in the case of target warning, the
DWELL algorithm can produce diagnostic output.
IRIS Product and Display User Guide M211319EN-H
146 RESTRICTED