With
A4:A600 containing a series of numbers that periodically rise then fall.
B4:B600 contains the same kind of fluctiating series...but with different values and periods.
Then...this ARRAY FORMULA, committed with CTRL+SHIFT+ENTER
(instead of just ENTER), returns the row number of the first Col_A peak.
C4: =SMALL(IF((A$5:A$599>A$4:A$598)*(A$5:A$599>A$6:A$600),ROW(A$5:A$599)),ROWS($4:4))
Copy C4 and paste into C5:C47
For the locations of the Col_B peaks....
Copy C4:C47 and paste into D4:D47.
Does that give you the kind of information you can work with?
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