World Ocean Circulation Experiment

World Ocean Circulation Experiment. It was a major component of the World Climate Research Programme and one of the largest international collaborative efforts ever undertaken in physical oceanography. The experiment aimed to observe the global ocean circulation system to understand its role in Earth's climate and improve predictions of climate change. It involved scientists from over 30 nations and utilized a vast array of ships, satellites, and autonomous instruments to collect an unprecedented dataset.

Background and objectives

The program was conceived in the late 1980s against a backdrop of growing concern about global warming and the recognition of the ocean's critical role in the climate system. Key scientific drivers included the need to quantify the ocean's transport of heat and freshwater, which are fundamental to the Earth's energy budget and global hydrological cycle. A primary objective was to establish a baseline description of the state of the global ocean, against which future changes could be measured, directly supporting the goals of the Intergovernmental Panel on Climate Change. The experiment also sought to test and improve the fledgling numerical models of the ocean general circulation, which were essential for projects like the Coupled Model Intercomparison Project.

Field program and components

The field phase, officially from 1990 to 1998, was a massive logistical undertaking coordinated by the Scientific Committee on Oceanic Research. The core hydrographic program involved numerous research vessels, such as those operated by the Scripps Institution of Oceanography and the National Oceanic and Atmospheric Administration, conducting precise measurements of water properties along globally repeated sections. A global network of autonomous Lagrangian drifters and subsurface floats was deployed to track currents at various depths. Satellite missions, including TOPEX/Poseidon and the European Remote Sensing Satellite, provided synoptic data on sea surface height and wind stress. Additional components focused on specific processes in regions like the Southern Ocean, the Weddell Sea, and the Equatorial Pacific Ocean.

Key findings and scientific impact

The experiment produced transformative insights, fundamentally altering the understanding of ocean dynamics. It provided the first truly global, quantitative description of the thermohaline circulation and the pathways of deep and bottom water masses, such as those formed in the North Atlantic Deep Water region. Data revealed the complexity of ocean eddy fields and their significant role in transporting heat and carbon, challenging simpler models of circulation. Measurements of anthropogenic tracers like chlorofluorocarbons offered direct evidence of how surface waters penetrate into the ocean interior, informing understanding of the ocean's uptake of atmospheric carbon dioxide. These findings were synthesized in major reports that became foundational texts for modern oceanography and climate modeling.

Data and legacy

A cornerstone of the program's philosophy was the immediate, open sharing of all collected data through designated national and international data centers, such as those at the National Center for Atmospheric Research. This vast, quality-controlled dataset remains a critical benchmark for model validation and climate studies. The infrastructure and protocols developed, particularly for the global float array, directly enabled the subsequent, ongoing Argo program, which now provides real-time monitoring of the upper ocean. The experiment also established standards for international collaboration in big science projects within environmental research, influencing the structure of later programs like CLIVAR and the Integrated Ocean Drilling Program.

Related and follow-on programs

The experiment was explicitly designed as the oceanographic cornerstone of the World Climate Research Programme, and its work was continued and expanded by several major initiatives. The Climate Variability and Predictability project directly extended its research agenda, focusing on climate variability on seasonal to centennial timescales. The global Argo program, an autonomous float array monitoring temperature and salinity, is a direct technological and scientific successor. Research on the ocean's carbon cycle was advanced by the subsequent Joint Global Ocean Flux Study and the modern Global Ocean Observing System. Insights into ocean-atmosphere interaction also fed into broader Earth system science projects coordinated by the International Geosphere-Biosphere Programme.

Category:Oceanography Category:Climate change assessment and attribution Category:Scientific experiments