Our oceans cover about 70 percent of Earth’s surface, and we’ve long known that they are integral to all known life and govern our weather and climate. In situ measurements taken in the water provide us with a wealth of information while hundreds of kilometres above the ocean surface, satellites are making their own measurements. Later this year Sentinel-3 will be joining the family of satellites observing the Earth and by combining the information from these with the continued ground-based measurements, we will have an even more accurate global perspective, helping us further understand our oceans.