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RISAn Efficient Dual-Resolution Approach for Ensemble Data Assimilation and Tests with Simulated Doppler Radar Data
Publisher: American Meteorological Society
Abstract: A new efficient dual-resolution (DR) data assimilation algorithm is developed based on the ensemble Kalman filter (EnKF) method and tested using simulated radar radial velocity data for a supercell storm. Radar observations ...
Generalized Adjoint for Physical Processes with Parameterized Discontinuities. Part VI: Minimization Problems in Multidimensional Space
Publisher: American Meteorological Society
Abstract: Generalized adjoint with modified discretization and generalized coarse-grain adjoint are derived for a vector system of equations that contains parameterized on/off switches. With vector examples, it is shown that the ...
Assimilation of Reflectivity Data in a Convective-Scale, Cycled 3DVAR Framework with Hydrometeor Classification
Publisher: American Meteorological Society
Abstract: he impact of assimilating radar reflectivity and radial velocity data with an intermittent, cycled three-dimensional variational assimilation (3DVAR) system is explored using an idealized thunderstorm case and a real data ...
Importance of Horizontally Inhomogeneous Environmental Initial Conditions to Ensemble Storm-Scale Radar Data Assimilation and Very Short-Range Forecasts
Publisher: American Meteorological Society
Abstract: The assimilation of operational Doppler radar observations into convection-resolving numerical weather prediction models for very short-range forecasting represents a significant scientific and technological challenge. ...
Can Gradient Information Be Used to Improve Variational Objective Analysis?
Publisher: American Meteorological Society
Abstract: A variational scheme for the analysis of scalar variables is developed and compared to two-pass and three-pass versions of the Barnes analysis scheme. The variational scheme, appropriate for diagnostic studies, is similar ...
A Variational Technique for Dealiasing Doppler Radial Velocity Data
Publisher: American Meteorological Society
Abstract: Velocity folding, or aliasing, is one of most significant impediments to the use of radial winds from Doppler weather radar. In this note, a variational algorithm is developed in which dealiasing is performed using wind ...
Some Observing System Simulation Experiments with a Hybrid 3DEnVAR System for Storm-Scale Radar Data Assimilation
Publisher: American Meteorological Society
Abstract: hybrid three-dimensional ensemble?variational data assimilation (3DEnVAR) algorithm is developed based on the 3D variational data assimilation (3DVAR) and ensemble Kalman filter (EnKF) programs with the Advanced Regional ...
Use of a Vertical Vorticity Equation in Variational Dual-Doppler Wind Analysis
Publisher: American Meteorological Society
Abstract: The utility of the anelastic vertical vorticity equation in a weak-constraint (least squares error) variational dual-Doppler wind analysis procedure is explored. The analysis winds are obtained by minimizing a cost function ...
Generalized Adjoint for Physical Processes with Parameterized Discontinuities. Part V: Coarse-Grain Adjoint and Problems in Gradient Check
Publisher: American Meteorological Society
Abstract: When on/off switches are triggered at discrete time levels by a threshold condition in a traditionally discretized model, the model solution is not continuously dependent on the initial state and this causes problems in ...
Baroclinic Eady Wave and Fronts. Part I: Viscous Semigeostrophy and the Impact of Boundary Condition
Publisher: American Meteorological Society
Abstract: A two-dimensional viscous semigeostrophic model is developed to study the evolution of the baroclinic Eady wave and fronts with two types (free-slip and nonslip) of boundary conditions. With the free-slip boundary condition, ...