# Optimal perturbation

From Glossary of Meteorology

## optimal perturbation

A perturbation that is intended to produce the largest (optimal) change to a forecast measure

*J*.For example, if

*J*is a measure of forecast error, an optimal perturbation δ*x*could represent a change to the forecast's initial conditions designed to minimize forecast error, given a constraint that δ*x*has magnitude comparable to the typical analysis errors of operational forecast models.*See*adjoint sensitivity.