Diabatic Dynamic Initialization with an Iterative Time Integration Scheme as a Filter

Abstract

Abstract A new diabatic dynamic initialization technique using an iterative time filter has been developed for an intermittent global data assimilation system. The diabatic dynamic initialization procedure has been implemented within the Goddard Earth Observing System (GEOS) Data Assimilation System employing the GEOS General Circulation Model. The initialization method employs only the forward full diabatic model integration as the initial balancing procedure. The initial balancing is accomplished efficiently by using a new iterative Euler scheme as a filter. The iterative Euler scheme converges rapidly after only a few iterations. It provides a filter most effective for the high-frequency and small-scale modes. The initial spinup effect is almost entirely eliminated, and initially disturbed external and internal modes are balanced by the initialization procedure during the first few time steps. After the short initialization procedure is completed, the standard model integration is continued with the re...