Ocean Data Assimilation: A Coastal Application

Abstract

The Navy Coupled Ocean Data Assimilation (NCODA) system is applied to a period during the Autonomous Ocean Sampling Network II (AOSN II) field campaign conducted in the Monterey Bay area in August 2003. The multivariate analysis of NCODA is cycled with the Navy Coastal Ocean Model (NCOM) in a sequential, incremental, update cycle. In addition to the operational data obtained from the Global Ocean Data Assimilation Experiment (GODAE) server, which included satellite observations of sea-surface temperature (SST) and sea-surface height and insitu surface and sub-surface observations of temperature and salinity, high-density data from aircraft SST observations and high-frequency data from buoys used for the AOSN II field experiment are also assimilated. The results from data assimilative and non-assimilative runs are compared with and verified against observations. Bias and root-mean-square errors of temperature indicate that forecast skill from the data assimilative run exceeds errors from the persistence and the non-assimilative runs. The seasonal thermocline is better represented and the warm bias for both upwelling and relaxation periods is significant reduced.