of time interpolation in the ensemble Kalman filter
Since 12 January 2005, an ensemble Kalman filter (EnKF) is being used
in Canada for global atmospheric data assimilation. It provides the
initial conditions for a medium-range ensemble prediction system.
Initial EnKF analyses were not of the same quality as the higher
resolution analyses that were obtained with a 4D-Var algorithm for the
high-resolution deterministic forecast at our center.
In part this was due to the lower resolution - and correspondingly
lower computational cost - of the EnKF. In part this was due to
weaknesses of the initial EnKF algorithm.
We have modified the EnKF algorithm and are working towards a clean
Peter Houtekamer and