Assimilation of satellite surface-height anomalies data into a Hybrid Coordinate Ocean Model (HYCOM) over the Atlantic Ocean

Abstract

The data of sea height anomalies calculated along the tracks of the Jason-1 and Jason-2 satellites are assimilated into the HYCOM hydrodynamic ocean model developed at the University of Miami, USA. We used a known method of data assimilation, the so-called ensemble method of the optimal interpolation scheme (EnOI). In this work, we study the influence of the assimilation of sea height anomalies on other variables of the model. The behavior of the time series of the analyzed and predicted values of the model is compared with a reference calculation (free run), i.e., with the behavior of model variables without assimilation but under the same initial and boundary conditions. The results of the simulation are also compared with the independent data of observations on moorings of the Pilot Research Array in the Tropical Atlantic (PIRATA) and the data of the ARGO floats using objective metrics. The investigations demonstrate that data assimilation under specific conditions results in a significant improvement of the 24-h prediction of the ocean state. The experiments also show that the assimilated fields of the ocean level contain a clearly pronounced mesoscale variability; thus they quantitatively differ from the dynamics obtained in the reference experiment.