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


	Rank histograms show whatÕs happening to the ensemble as the filter length scale is varied.
	Trend toward too much population at extreme ranks when length scale increased (then filter divergence).
	When filter length scale is too short, not enough population at extreme ranks (too much variance, because ensemble is not corrected enough far away from ob).