Comparison of the Ensemble and Hybrid Approaches for Estimating Observation Impact
Recently, a new approach for estimating the impact of the assimilated observations on forecasts has been developed, which is appropriate for EnVar data assimilation. It does not require the adjoint of the forecast model and shares components of both the standard adjoint approach and purely ensemble approaches for estimating observation impact. The estimated impacts obtained with the new approach are compared with those obtained with a purely ensemble approach developed for application to the EnKF. The impact of observations during the North Atlantic Waveguide and Downstream Impact Experiment (NAWDEX) will be presented. Comparison of these estimates with a non-cycled data denial experiment will also be discussed.
Dr. Ping Du Environment and Climate Change Canada