• In the Local Ensemble Kalman
Filter we compute the generalized “bred vectors”
globally but use them locally (3D patches around
each grid point of ~1000km x 1000km).
• These local patches (vertical
columns) provide the local shape of the
“errors of the day” for each grid point.
• At the end of the local analysis
we create a new global analysis and
initial perturbations from the solutions obtained at each grid point.
• This reduces the number of ensemble members needed.
• It also allows to compute the KF analysis independently at each grid point (“embarrassingly
parallel”).