|Title||Linearized physics for data assimilation at ECMWF|
|Year of Publication||2012|
|Authors||Janiskova, M, Lopez, P|
|Secondary Title||Technical Memorandum|
|Type of Work||Technical Memorandum|
A comprehensive set of linearized physical parametrizations has been developed for the global ECMWF Integrated Forecasting System. Implications of the linearity constraint for any parametrization scheme, such as the need for simplification and regularization, are discussed. The description of the methodology to develop linearized parametrizations highlights the complexity of obtaining a physics package that can be efficiently used in practical applications. The impact of the different physical processes on the tangent-linear approximation and adjoint sensitivities, as well as their performance in data assimilation are demonstrated.