Estimating Global Ocean indicators from a gridded hydrographic field during 2003-2008

Monthly gridded fields of temperature and salinity of the upper 2000m depth are obtained by optimal analysis of the large in-situ dataset provided by the Argo array of profiling floats, drifting buoys, CTDs and moorings over the period 2003-2008. These fields are used to analyze large-scale and deep variability patterns on interannual time scales during the 6 years of measurements with the substantial advantage that this study is based on a single and uniform data base. Global and basin wide averages of ocean indicators such as heat storage anomalies, freshwater content and steric height have been estimated from the gridded monthly field. We find global average rates of 0.77±0.11Wm -2 for heat storage, 700±1600km 3 /a for freshwater content and 1.01±0.13 mm/a for steric sea level. The horizontal distribution of these ocean indicators shows largest variability of heat storage and steric height in the North Atlantic Ocean, in the northern tropical Pacific and in the South Pacific. Freshwater content changes from 2003 to 2008 are dominant in the tropical and subtropical basins of the global oceans and are dominated by interannual fluctuations. Variability patterns of steric and total sea level are in good agreement between 30°S-50°N during the 6 years of measurements.