Ground control to major tides - Mapping the Earth's surface water levels from above

The Surface Water and Ocean Topography (SWOT) mission is a pioneering three-year Earth ­orbiting satellite launched in December 2022 to map the Earth's surface water levels and assess freshwater resources in unprecedented detail. The SWOT standard low ­resolution products provide images of surface water levels globally, at 2km spatial resolution in two adjacent 60km swaths. SWOT high-resolution products are finer still, allowing rivers wider than 100m to be resolved over the Earth's landmasses and coastal areas at latitudes between 78' N and 78' S - to near-centimetric vertical accuracy. Existing nadir-pointing satellite altimeters flown for the past 30 years provide only single tracks of data at widely spaced intervals.