Data collected from deep ocean robots has allowed the National Oceanic and Atmospheric Administration (NOAA) to better understand the warming of the world’s oceans.
NOAA’s Argo Program, which utilizes robotic floats that descend three to four miles under the ocean’s surface to collect data on ocean temperature and salinity, has increased the U.S. government’s confidence that deep ocean waters are warming at a rate of 0.0036 to 0.0072 degrees Fahrenheit (0.002 to 0.004 degrees Celsius) annually.
The Argo Program noted two deep ocean warming “hot spots” — one off the coast of Antarctica, and the other off the coast of Greenland. According to NOAA, the warm waters near Antarctica travel north, much like a conveyor belt, contributing to warming waters in areas around the world. This conveyor belt effect, known as global meridional overturning circulation, helps scientists predict weather and climate changes.
“Ocean warming is the dominant element of global warming and a major driver of climate change,” said Greg Johnson, an oceanographer at NOAA’s Pacific Marine Environmental Lab. “This study confirms the previously reported deep ocean warming and reduces the uncertainties about the global ocean heat uptake in waters below 1.2 miles, a key area of the ocean for predicting sea level rise and extreme weather.”
NOAA’s first Deep Argo float launched in 2014 off the coast of New Zealand. Since then, these satellite-linked robotic floats have expanded their coverage to greater areas of the Southwest Pacific, the South Atlantic off Brazil and Argentina, the South Indian Ocean between Australia and Antarctica and the North Atlantic between Florida and North Africa.
“Right now, Deep Argo consists of pilot arrays in key regions,” said Johnson. “If we can build a global array, we’ll be able to quantify the warming rate over shorter periods of time to see how that rate is changing. We have hints that the rate is changing but we need to be able to tease that out better. Measuring evolving temperature salinity patterns in the deep ocean will also aid in predicting climate changes decades in advance.”
