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SHADOWING IN THE ATMOSPHERE. Ross Lieb-Lappen Chris Danforth. Forecasting Challenges. Uncertainty in the initial state Chaos: sensitive dependence on initial conditions Model error. Trajectory of the System Truth. Forecast of the System Truth. Improving the Forecast. Our Model.
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SHADOWING IN THE ATMOSPHERE Ross Lieb-Lappen Chris Danforth
Forecasting Challenges • Uncertainty in the initial state • Chaos: sensitive dependence • on initial conditions • Model error
Our Model Image: Nick Allgaier
Forecasting Methodology • Ensemble forecasting • Lorenz ‘96 Model • Define new ensemble members • Inflation of forecast ellipsoid external forcing advection dissipation
Controlled Inflation • Only in contracting directions • Within climatological span • of particular variable • Maintain appropriate ratio • with neighboring values
Acknowledgments Advisor: Chris Danforth Nick Allgaier Kameron Harris
Singular Value Decomposition Definition of new ensemble members