Change in Weather Research and Forecasting (WRF) Model Accuracy with Age of Input Data from the Global Forecast System (GFS)

Report No. ARL-TR-7782
Authors: James L Cogan
Date/Pages: September 2016; 44 pages
Abstract: Mesoscale models generate output for many applications worldwide. Normally, initialization of a mesoscale model employs the most recent output available from a larger-scale regional or global model. Such output also is used to adjust the lateral boundary conditions as the larger-scale model evolves. However, some applications, especially in remote or minimally connected areas, may require the use of large-scale model data that may be one or more days old. The analysis of this report investigates the effect of using older large-scale data on mesoscale model accuracy. The report briefly describes the procedure and presents the results of a preliminary analysis. As expected, accuracy generally tended to decline as the large-scale data aged, but appeared to improve slightly as the age of the large-scale data increased from 3 days old to 4 days old. Also, there is a wide variation between individual cases. The change in meteorological variables is explored, but the emphasis is on the effect on simulated artillery trajectories. The use of trajectories with their major dependence on meteorological conditions provides a means to check the net overall ability of a model to simulate the atmosphere over the space and time covered by the trajectory.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2016