Observing Our Changing Oceans

Deployment of an Argo float.

Deployment of an Argo float.

High resolution (Credit: NOAA)

Changes in the ocean and atmosphere affect all aspects of our lives, from deciding what crops to plant to where to spend a vacation. How we understand and predict regional and global climate changes can provide enormous benefits such as helping inform decisions on responding to a changing environment. Measuring changes in the ocean is the first step towards that goal.

In the past, measuring changes in sea temperature, salinity, and currents were restricted to research ships, moored buoys, and commercial vessels that were in a specific location or shipping lane. This left large areas of the ocean unobserved and measuring was often restricted to periods of favorable weather and the data collected were often limited to relatively shallow depths of roughly 750 meters (2,460 feet).

Operation of an Argo float.

Operation of an Argo float.

High resolution (Credit: NOAA)

Today, an international ocean-observing program known as "Argo" (named after the ship Argo in Greek mythology) provides critical temperature and salinity data. The Argo program initiated an era of global oceanographic monitoring with quality-controlled, real-time data availability to improve knowledge of the world’s oceans.

Argo floats are deployed at the sea surface. Over a 10-day period, the floats sink to 1,000 meters (3,280 feet) collecting data on the descent. The floats rest at that depth for a prescribed period and rise back to the surface, also collecting data on the rise.

Argo float locations.

Argo float locations.

High resolution (Credit: NOAA)

At the surface, the floats transmit, to satellites, their position and send the entire collected oceanographic data. The battery powered floats then sink again to repeat the cycle. Over the course of an average lifetime, an Argo float completes about 150 cycles over a four-year life span.

The first Argo float was released in 1999. Today there are roughly 3,150 floats providing data for a four-year life span per float.

Argo has helped to transform our ability to monitor temperature and other changes in the ocean.  Thanks to this innovation we continue to learn more about how climate change is affecting the planet.  NOAA logo.