Description of the ARM Operational Objective Analysis System

This report describes the Atmospheric Radiation Measurement (ARM) operational variational objective analysis system. It is currently used to process data collected from the ARM intensive operational periods (IOPs) for driving and evaluating physical parameterizations in climate models. The analysis system was originally developed by Zhang and Lin (1997) at the State University of New York (SUNY) at Stony Brook and was migrated to the Lawrence Livermore National Laboratory (LLNL) as the ARM operational objective analysis system in May 1999. In contrast with previous objective analysis (e.g., Barnes 1964; O’Brien 1970; Lin and Johnson 1994) the ARM objective analysis used the constrained variational analysis method in which the atmospheric state variables are forced to satisfy the conservation of mass, heat, moisture, and momentum. The purpose of this technical report is to provide an overview of the constrained variational analysis method, the architecture of the objective analysis system, along with in-depth information on running the variational analysis codes