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RISNonlinear Stability Theorem for Eady's Model of Quasigeostrophic Baroclinic Flow
Publisher: American Meteorological Society
Abstract: In this paper, the linear stability criterion for Eady's problem is proved to be also a nonlinear stability one. Upper bounds for the disturbance potential enstrophy, the disturbance energy, and the disturbance available ...
Impact of Horizontal Diffusion on the Nonlinear Stability of Thermohaline Circulation in a Modified Box Model
Publisher: American Meteorological Society
Abstract: This note studies the impact of horizontal diffusion (HD) on the thermohaline circulation (THC) within a modified Stommel?s box model, which was introduced by Longworth et al. HD may arise as a result of mesoscale eddies ...
A Method to Find Perturbations That Trigger Blocking Onset: Conditional Nonlinear Optimal Perturbations
Publisher: American Meteorological Society
Abstract: In this paper the following question is addressed: assuming that some information is available about initial perturbations (e.g., that they belong to an ensemble, which consists of the perturbations whose magnitudes are ...
Similarities between Optimal Precursors that Trigger the Onset of Blocking Events and Optimally Growing Initial Errors in Onset Prediction
Publisher: American Meteorological Society
Abstract: triangular T21, three-level, quasigeostrophic global spectral model was used to investigate how precursors relate to the predictability of blocking onset when a conditional nonlinear optimal perturbation approach is used. ...
Zigzag Oscillations in Variational Data Assimilation with Physical “On–Off” Processes
Publisher: American Meteorological Society
Abstract: Using an idealized model of a partial differential equation with parameterization ?on?off? switches in the forcing term, the impacts of on?off switches on the variational data assimilation (VDA) are investigated in this ...
Conditional Nonlinear Optimal Perturbations of a Two-Dimensional Quasigeostrophic Model
Publisher: American Meteorological Society
Abstract: Conditional nonlinear optimal perturbations (CNOPs) of a two-dimensional quasigeostrophic model are obtained numerically. The CNOP is the initial perturbation whose nonlinear evolution attains the maximum value of the cost ...
A Study on the Reduction of Forecast Error Variance by Three Adaptive Observation Approaches for Tropical Cyclone Prediction
Publisher: American Meteorological Society
Abstract: hree adaptive approaches for tropical cyclone prediction are compared in this study: the conditional nonlinear optimal perturbation (CNOP) method, the first singular vector (FSV) method, and the ensemble transform Kalman ...
A Method for Adjoint Variational Data Assimilation with Physical “On–Off” Processes
Publisher: American Meteorological Society
Abstract: Since the accuracy of the tangent linear approximation of moist physics in a mesoscale model is case dependent, the problem related to the variational data assimilation with physical ?on?off? processes is studied further ...
Nonlinear Stability of the Generalized Eady Model
Publisher: American Meteorological Society
Abstract: Linear and nonlinear stability theorems for the generalized Eady model are obtained by the normal-mode method and the energy?Casimir method, respectively. The nonlinear stability criterion is optimal in the following sense: ...
Influence of Physically Constrained Initial Perturbations on the Predictability of Mei-Yu Heavy Precipitation
Publisher: American Meteorological Society