18th Conference on Weather and Forecasting, 14th Conference on Numerical Weather Prediction, and Ninth Conference on Mesoscale Processes

Monday, 30 July 2001: 1:40 PM
Implementation of the NRL Atmospheric Variational Data Assimilation System
Edward Barker, NRL, Monterey, CA; and R. Daley and J. Goerss
Poster PDF (107.1 kB)
NAVDAS is a global three-dimensional variational analysis system providing temperature, wind, and specific humidity analyses on pressure surfaces, and configured to run on a massively parallel computer. Observations are passed through preprocessing and data quality control algorithms prior to being analyzed. Additional quality control decisions are made using the analysis algorithm, which serves as a buddy check that is sensitized by the variance of the localized innovation vector and the surface pressure change surrounding the analysis time.

NAVDAS is tested and compared to the existing operational system, a multivariate optimal interpolation scheme using the Navy Operational Global Atmospheric Prediction System. Initial comparisons are made with both systems configured as close to one another as possible. Additional comparisons are used to compare individual cases as well as a statistical validation over different seasons. Incremental addition of NAVDAS features are then tested and compared to the baseline run established using the earlier comparison runs.

In this presentation, NAVDAS performance will be described to include computer efficiency, forecast improvement, and details in the resulting analyses.

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