Dynamic Data Assimilation by the Noise Freezing Method.

Abstract : A barotropic model was developed using a variational method to conserve mass and total energy. This model was then used to assimilate satellite data by adjusting the fluid depth so that gravity waves moved at about the same speed as meteorological waves. The analyses resulting from the assimilation runs were used to adjust the 1000-500 mb thickness in a baroclinic forecast system. Although results were obtained from only one experiment, they show some promise for improving forecasts, particularly in the southern hemisphere. A baroclinic global model was then developed so that the gravity waves could be decreased in speed during the period of data assimilation of satellite data. Initial tests suggest that imbalances in the model caused by data insertion can be controlled, thereby allowing a more accurate analysis of the satellite data. (Author)