Abstract
The expected error variance associated with a kinematic estimation of vertical motion is examined for the case of a linear piecewise integration of the vertical profile of horizontal wind divergences. It is demonstrated that for the type of divergence error variation with height often assumed in applying O'Brien's (1970) adjustment scheme, an optimal adjustment actually offers little advantage over a more straightforward constant bias correction rule. It is suggested that other methods for estimating kinematic errors other than by assuming these are wholly due to wind-observing error might be required before optimal bias correction methods can be used to full advantage.