Ocean Salinity

In this video from the EUMETSAT Monitoring the Oceans from Space course, Dr Chris Banks from the National Oceanography centre (NOC), tells us about ocean salinity and its impacts on the water cycle, ocean currents and the global climate.

Everyone knows the ocean is salty, but how salty it is varies depending on where you measure it. Input from rivers and rain can alter the oceans salinity, by adding fresh water.

Sea surface salinity is a key variable for understanding density-driven ocean circulation, including the large-scale overturning circulation that redistributes heat and nutrients around the planet. It is also an important indicator of changes in the global water cycle and climate variability.

Since 2009, ocean salinity has been directly observed from space using dedicated satellite missions, beginning with ESA’s SMOS mission, followed by NASA’s Aquarius mission (2011–2015) and continuing with NASA’s SMAP mission, which also provides salinity estimates. Together, these satellites have established a long-term, global record of sea surface salinity.

Today, satellite salinity measurements are routinely combined with in situ observations, such as Argo floats, and assimilated into operational ocean and climate models. This integrated observing system improves our ability to simulate and predict ocean circulation and its role in the Earth’s climate system.