Blending Scheme with Mixed Truncation Scale and Its Application in Southwest Regional Model

The complex and diverse topography of the southwest region generates disastrous weather systems with multi-scale characteristics， and fluctuation information of each scale affects the occurrence and development of the weather systems.In order to introduce the information from the background field of the global model in a timely and appropriate approach during the update cycle assimilation process， and to correct the bias of the regional model in the analysis and forecasting of large-scale waveform information， this paper takes the southwest region as the research background， setting the truncation scale of wind field and the truncation scale of temperature & humidity variables differently according to the length scale characteristics of different types of model variables.A blending scheme with mixed truncation scale is proposed， and a one-week continuous batch update cycle assimilation experiments and diagnostics of one case are carried out based on the southwest regional update cycle assimilation system.The