PowerPoint Presentation - Methods for dealing with spurious covariances arising from small samples in ensemble data assimilation

Outstanding issues

•Both methods assume a priori that covariance is maximized at the observation location - problematic for non-local and time-lagged obs.

•Both methods are flow-independent (assume same degree of locality for every situation).

•Localization can destroy balance.


	Both method have deficiencies - the localization is the same all the time, and geostrophic balance is not maintained.