Abstract: It has been demonstrated previously by both analysis and numerical integration that there is a serious problem incorporating orographic forcing into semi-implicit semi-Lagrangian models, since spurious resonance can develop ...

Abstract: A modification is introduced in a semi-implicit version of a grid point model of the shallow water equations. The new model is simpler, runs one-third, and after 5 days of integration, the forecasts differ by less than 1 m.

Abstract: A four-dimensional variational (4DVAR) data assimilation problem may be constrained so that the solution closely fits the observations but is balanced. In this way, the processes of data analysis and initialization are ...

Abstract: This study examines the linearization properties of a simplified planetary boundary layer parameterization based on the vertical diffusion equations, in which the exchange coefficients are a function of the local Richardson ...

Abstract: The semi-implicit algorithm, originally developed by Robert for an economical integration of the primitive equations in large-scale models of the atmospheric, is here generalized in order to integrate the fully compressible, ...

Abstract: The tangent linear model (TLM) is obtained by linearizing the governing equations around a space- and time-dependent basic state referred to as the trajectory. The TLM describes to first-order the evolution of perturbations ...

Abstract: s a second step in the development of the Canadian Regional Data Assimilation System following Fillion et al., this study extends the approach to the four-dimensional variational data assimilation (4D-Var) context. Emphasis ...

Abstract: A modified semi-Lagrangian scheme is proposed in the context of semi-implicit forecast models to reduce the important distortion of topographically forced waves that is produced when the Courant?Friedrichs?Lewy (CFL) number ...

Abstract: On 15 March 2005, the Meteorological Service of Canada (MSC) proceeded to the implementation of a four-dimensional variational data assimilation (4DVAR) system, which led to significant improvements in the quality of global ...

Abstract: A four-dimensional variational data assimilation (4DVAR) scheme has recently been implemented in the medium-range weather forecast system of the Meteorological Service of Canada (MSC). The new scheme is now composed of ...