Summary of
NWP equations (cont.)
The analysis error
covariance is given by
This can also be written
as
ÒThe
analysis precision is given by the sum of the background and observation precisionsÓ
ÒThe analysis covariance is reduced from the background covariance by a factor (I - scaled optimal gain)Ó
ÒThe variational approach and the sequential approach are solving the same problem, with the same K, but only KF (or EnKF) provide an estimate of the analysis error covarianceÓ