The methodology used to track Solar electron and proton flux and
fluence, as written in 2000, is very convoluted and messy. Boiled down
to its essentials, with a bit of oversimplification, every 5 minutes
the following occurs:
After a while we were getting bogus values from the ACE EPAM page
- the flux would go from, say, 59 to 200,000 and then back to 59 in
three consecutive readings. These huge jumps set off alarms which
So around 2010 or so I modified acis-P3-fluence.pl to compare those old and
new values and if the absolute value of the delta between them were
over a certain value, to ignore that new value, and re-use the old
value. The delta selected was 100,000. This eliminated bogus alerts
without missing any real jumps.
The ACE EPAM file is updated every 5 minutes, and so is acis-P3-fluence.pl. So a few bogus values
would result in re-using the old value a few times but the typical
delta in the real, nominal case isn't that much.
When a bogus jump is detected, the "new" value is set to the "old"
value, that old value gets written out in Step 5 above. So if the subsequent 5 minute entry in the ACE EPAM file is also bogus, or comes back down to "normal" (i.e. less than 100,000 away from the "old" value) it will be used.
The pseudo-code for this is:
The contents of ACE-flux.dat is updated by another program.