qThe optimum interpretation (OI) is a linear interpretation which requires its root-mean square error
to be minimum.
qThe discussion of this method focuses on the “deviations from a normal state”:
qLet’s say we have a variable f and its normal state f norm. This normal state can be the climatological value of f or a first guess of f.
qThen we can define the deviation of f from its normal state as f’: