The saltiness of the sea surface varies depending on where and when you're looking. Heavy rainfall, river outflows, ocean currents, sea ice melt, evaporation and other seasonal phenomena can all alter salinity—and scientists can now see these changes in clear detail. NASA's Aquarius mission has collected the agency's first full year of satellite ocean surface salinity measurements, revealing a colorful and dynamic portrait of our salty seas. Salinity shifts, a powerful driver of global ocean currents, are also a fingerprint of variations in Earth's fresh water cycle, providing valuable information on how a changing climate is altering global rainfall patterns. Before Aquarius, researchers had only snapshots of the ocean's salt content variations. With global satellite measurements, they will now be able to see how salinity changes over time. Watch the video to learn more about our ocean's salty motions.