Within the past decade, satellite observations of ocean color have provided a global view of biology within the ocean's surface layer and revealed how phytoplankton abundance varies in response to various physical forcings ranging from the large scales of seasonal cycles and the El Niño-Southern Oscillation, to planetary waves, eddies, and coastal filaments at smaller scales. The maturing Argo network of profiling floats now provides a way to put these remote sensing measurements into a vertical context.
The true test of any scientific discipline is prognostic capability. In physical oceanography, the ocean dynamics are fairly well understood, and their prediction hinges on the measurement of key variables at the proper spatial and temporal scales so as to validate and initialize models. Remote sensing coverage of these key parameters, such as sea surface temperature and height anomalies, has been available for 30 and 15 years, respectively. As a result, recent advances in numerical modeling are bringing operational forecasting of ocean circulation within reach.