Application of Argo data in science

Argo data are fundamental to modern ocean and climate science. They are used to study ocean warming and heat uptake, circulation and water-mass formation, sea-level change, climate variability, ocean–atmosphere interactions and the global water cycle. With the expansion of BGC-Argo and Deep Argo, observations are also enabling new research into ocean carbon cycling, acidification, deoxygenation, marine ecosystems and deep-ocean change. Argo observations are further used to validate satellites and improve ocean models, reanalyses and forecasting systems.

  • Ocean warming and climate change
    Argo provides continuous observations of temperature and salinity throughout the upper 2,000 m, allowing scientists to quantify ocean warming and heat uptake. These observations are used to identify long-term climate trends, investigate changes in ocean heat content and assess how the ocean responds to a changing climate.

  • Ocean circulation and water masses
    Argo profiles reveal the three-dimensional structure of the ocean and are used to investigate currents, water-mass formation, mixing and transport. Repeated observations help scientists track how water masses move and change over time, including processes associated with major circulation systems such as the Atlantic Meridional Overturning Circulation (AMOC).

  • Sea-level change
    Changes in temperature and salinity alter the volume and density of seawater. Argo measurements are combined with satellite altimetry and other observations to separate the different contributions to sea-level rise, including thermal expansion and changes in ocean freshwater content.

  • The global water cycle
    Salinity measurements provide an important window into the movement of freshwater through the ocean. Scientists use Argo to investigate changes in evaporation, precipitation, river input, ice melt and freshwater transport, helping to understand how the global water cycle is changing.

  • Marine heatwaves and extreme events
    Argo observations allow scientists to look beneath the surface during events such as marine heatwaves. This helps determine how deeply extreme warming penetrates, how much heat is stored in the ocean and how these events develop and dissipate.

  • Ocean biogeochemistry and the carbon cycle
    BGC-Argo floats measure variables including oxygen, pH, nitrate, chlorophyll and optical properties. These observations are used to study ocean productivity, nutrient cycling, carbon uptake, ocean acidification and deoxygenation, providing insights into the ocean's role in regulating atmospheric carbon dioxide.

  • Marine ecosystems and productivity
    Measurements such as chlorophyll and backscatter provide information about phytoplankton and particles in the ocean. Combined with physical observations, these data help scientists investigate changes in biological productivity, plankton communities and marine ecosystem dynamics.

  • Deep-ocean change
    Deep Argo extends profiling to depths of up to 6,000 m, opening new opportunities to study the relatively poorly observed deep ocean. These observations can reveal changes in deep-ocean temperature, salinity, water masses and circulation, and improve our understanding of where excess heat and carbon are stored.

  • Ocean modelling and forecasting
    Argo observations are assimilated into numerical ocean models and reanalyses to improve estimates of the ocean's current state. They are therefore fundamental to ocean forecasting, climate prediction and model evaluation, helping scientists test whether models correctly represent observed ocean variability and change.

  • Satellite validation and integration
    Argo provides high-quality measurements beneath the ocean surface that complement satellite observations. Scientists use Argo profiles to validate satellite products such as sea-surface temperature, salinity and ocean colour, and to combine surface and subsurface observations for a more complete picture of the ocean.