The global ocean observing system

In the last 20-30 years, much progress has been made in the deployment of sustained, nationally and internationally coordinated ocean observing programs. These include the Argo array of profiling floats, ocean glider missions, the global drifter array, Ships of Opportunity (SOOP) eXpendable Bathythermograph (XBT) lines, deep water moorings, Global Ocean Ship-based Hydrographic Investigation Program (GOSHIP), and new pilot studies extending to boundary currents, the deep ocean, and the marginal ice zones. In general, many of the observing systems were originally designed to resolve ocean variability at timescales from sub-seasonal to longer; however, the data are now also essential for ocean forecasting and prediction projects. Improved satellite technologies and telecommunications has enabled much of the ocean observations data to be recovered in real-time. The advent of rapid and timely access to data has led to the increasing use of ocean data in operational oceanography systems for the purpose of providing increasing accurate and reliable global and regional ocean (eddy resolving) forecasts. In this chapter, we provide an overview of the global in situ ocean observing systems for measuring physical Essential Ocean Variables (EOVs), including all the major platforms, and the efforts of the international coordinating programs.