Global Array Tracks Climate Changes

Argo's global array of profiling floats will provide a major contribution to the Global Ocean Observing System (GOOS) and the Global Climate Observing System (GCOS). The Intergovernmental Oceanographic Commission (IOC) and the World Meteorological Organization (WMO) endorse Argo. The floats return to the sea surface at regular intervals and data are transmitted via satellite for processing. A significant improvement is expected in data coverage, particularly in the remote ocean regions where floats can be deployed via airdrops. In October 2007 it achieved its goal of 3000 operating floats. These are providing around 100,000 observations each year, throughout all the ice-free deep-ocean areas of the world. Around 800 floats will need to be deployed each year to maintain the 3000-float array. Argo is a collaborative effort involving 28 countries; the U.S. is the largest single supplier of probes to the project. Scientists at U.S. Naval Research Laboratory, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration and elsewhere use the data to predict ocean behavior, forecast weather, and track climate change. Now the program plans to send newly designed probes to depths of 4,000 or even 6,000 meters in hopes of better understanding the ocean’s changing characteristics. Teledyne Webb Research’s newest probe, the APEX, recently set a record off the coast of Hawaii’s Big Island by descending to well below 4,000 meters. Besides float deployment, Argo has worked to develop two separate data streams: real time and delayed mode. A real time data delivery and quality control system has been established that delivers 90% of profiles to users via two global data centers within 24 hours. A delayed mode quality control system (DMQC) has been established and 60% of all eligible profiles have had DMQC applied. Float reliability has improved each year and the float lifetime has been extended. Argo has developed a large user community in universities, government labs and meteorological/climate analysis/forecasting centers. The need for global Argo observations will continue indefinitely into the future, though the technologies and design of the array will evolve as better instruments are built, models are improved, and more is learned about ocean variability.