The BMRC regional data assimilation system

Abstract

A new limited-area data assimilation system has been developed in the BMRC for operational use by the Australian Bureau of Meteorology. The system analyzes deviations from a primitive equations model forecast, using two-dimensional univariate statistical interpolation (SI) to analyze mass, and three-dimensional univariate SI to analyze wind data. Mass and wind increment analyses may mutually influence the other using variational techniques. This paper describes in detail the analysis methodology, and presents results from a 17-day trial period. Prognoses from this trial period show a much more rapid spinup of forecast rainfall rate than did a series of control forecasts based on operational analyses, and both mean rainfall for the 17-day period and individual cases are presented to demonstrate improved skill of forecasts from the assimilated analyses. -from Authors