Abstract: Due to its prohibitive computational cost, variational nonlinear normal mode initialization has received little interest during the last 10 years. Recently, soon after the introduction of the framework now called implicit ...

Abstract: The degree of imbalance forced by deep convection in a three-dimensional variational analysis scheme (3DVAR) is examined. Simulated surface precipitation rates are used with various degree of errors together with different ...

Abstract: It is shown that implicit normal mode initialization can be combined with a variational technique, in order to control the relative magnitudes of the changes to the analyzed mass and wind fields. Since the initialization ...

Abstract: Recent studies have demonstrated that variational nonlinear normal-mode initialization can be efficiently implemented in the context of shallow-water models, provided one uses a physical space formulation. The implicit ...

Abstract: Some basic aspects related to the problem of incorporating moist convective processes in a variational data assimilation framework are considered. The methodology is based on inverse problem theory and is formulated in its ...

Abstract: Advanced operational four-dimensional variational data assimilation (4DVAR) schemes include a linearized version of moist convective parameterization and its adjoint. At the Meteorological Service of Canada, work is underway ...

Abstract: A detailed examination of the Jacobian matrix of sensitivities of the prognostic cloud scheme operational at the European Centre for Medium-Range Weather Forecasts (ECMWF) is presented. These Jacobians exhibit sensitivities ...

Abstract: This study examines the modification to the balance properties of the analysis increments in a global three-dimensional variational data assimilation scheme when using flow-dependent background-error covariances derived ...

Abstract: Some problems posed by the coupling of moist-convective and stratiform precipitation processes for variational assimilation of precipitation-rate data are examined in a 1D-Var framework. Background-error statistics and ...

Abstract: The differences in the balance characteristics between dry and precipitation areas in estimated short-term forecast error fields are investigated. The motivation is to see if dry and precipitation areas need to be treated ...