Wednesday, 1 August 2001: 1:00 PM
A Comparison of Mesoscale Model Forecast Accuracy Using Random and a Simplified Targetting Approach
Recent results (Kuypers 2000, Nuss et al. 2000) suggest that
fine resolution mesoscale model forecast error has similar
characteristics independent of the random sampling strategy
employed in defining the initial atmospheric state. Each
simulation showed that fine resolution mesoscale model
forecast error was primarily due to subtle errors in the
definition of relevant synoptic-scale features in both a
winter and summertime case study. Current operational methods
which attempt to define the important relevant synoptic-scale
features on a given day typically use a tangent linear model
to deduce volumes of the atmosphere where the model is most
sensitive at the time of initialization given a chosen forecast
parameter of interest. This presentation will focus on a simpler
approach whereby the important relevant synoptic-scale structure
is defined as the locations required mathematically to reasonably
define the three dimensional atmospheric structure to within
some predefined degree of accuracy. A comparison will be made
between the mesoscale model forecast error using random sampling
and the simplified targetting approach.
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