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A Comparison of Analysis and Forecast Correction Techniques:Impact of Negative Dissipation
Publisher: American Meteorological Society
Abstract: The impact of negative dissipation on posttime analysis and forecast correction techniques is examined in a simplified context. The experiments are conducted using a three-level quasigeostrophic model (with a nonsingular ...
Stochastic Nature of Physical Parameterizations in Ensemble Prediction: A Stochastic Convection Approach
Publisher: American Meteorological Society
Abstract: In this paper it is argued that ensemble prediction systems can be devised in such a way that physical parameterizations of subgrid-scale motions are utilized in a stochastic manner, rather than in a deterministic way as ...
Time Step Sensitivity of Nonlinear Atmospheric Models: Numerical Convergence, Truncation Error Growth, and Ensemble Design
Publisher: American Meteorological Society
Abstract: Computational models based on discrete dynamical equations are a successful way of approaching the problem of predicting or forecasting the future evolution of dynamical systems. For linear and mildly nonlinear models, the ...
Western Pacific Warm Pool Region Sensitivity to Convective Triggering byBoundary Layer Thermals in the NOGAPS Atmospheric GCM
Publisher: American Meteorological Society
Abstract: The sensitivity of the atmospheric general circulation model of the Navy Operational Global Atmospheric Prediction System to a parameterization of convective triggering by atmospheric boundary layer thermals is investigated. ...
Impact of Stochastic Convection on Ensemble Forecasts of Tropical Cyclone Development
Publisher: American Meteorological Society
Abstract: Two versions of the Navy Operational Global Atmospheric Prediction System (NOGAPS) global ensemble, with and without a stochastic convection scheme, are compared regarding their performance in predicting the development ...
Sensitivity of Tropical Cyclone Forecasts as Revealed by Singular Vectors
Publisher: American Meteorological Society
Abstract: Singular vector (SV) sensitivity, calculated using the adjoint model of the U.S. Navy Operation Global Atmosphere Prediction System (NOGAPS), is used to study the dynamics associated with tropical cyclone evolution. For ...
Convergence of Singular Vectors toward Lyapunov Vectors
Publisher: American Meteorological Society
Abstract: The rate at which the leading singular vectors converge toward a single pattern for increasing optimization times is examined within the context of a T21 L3 quasigeostrophic model. As expected, the final-time backward ...
Implications of Regime Transitions for Mountain-Wave-Breaking Predictability
Publisher: American Meteorological Society
Abstract: A suite of high-resolution two-dimensional ensemble simulations are used to investigate the predictability of mountain waves, wave breaking, and downslope windstorms. For relatively low hills and mountains, perturbation ...
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Publisher: American Meteorological Society
Linkages between Potential Vorticity Streamer Activity and Tropical Cyclone Predictability on Subseasonal Time Scales
Publisher: American Meteorological Society