![]() The Intergovernmental Panel on Climate Change recently concluded that glacial melt and ice sheet loss are the dominant contributors to global mean sea level rise. Credit: NASA's Goddard Space Flight Center. The mission is being developed in collaboration with the European Space Agency, the European Organisation for the Exploitation of Meteorological Satellites, and NOAA.Īntarctic ice sheet mass loss with superimposed ice sheet velocity streamlines from 2002 to 2016. Launching in November, 2020, the new Sentinel-6 Michael Freilich mission is a follow-on to the Jason altimeter missions and will ensure the continuation of a decades-long record of sea level observations through at least 2030. Starting in August 1992, four satellite missions have provided a long time series of sea surface height: the TOPEX/Poseidon (T/P) altimetric mission, a joint effort between NASA and the French space agency Centre National d'Etudes Spatiales Jason-1 the Ocean Surface Topography Mission (OSTM)/Jason-2 and now the ongoing Jason-3. These measurements are used to calculate Global Mean Sea Level. Satellite altimeters very accurately provide measurements of sea surface height by timing a roundtrip radar signal from the satellite to the ocean surface and back to the satellite. Earth’s geoid is defined as the mean sea surface due to the pull of gravity on the ocean. When scientists refer to changes in sea level, they are referring to changes in the height of the mean sea surface relative to a mean sea level defined by Earth’s geoid. The new Sea Level Change Data Pathfinder delves into many of the datasets scientists use to study the status of global and regional sea level change. Piecing together the drivers of sea level change requires a diversity of datasets and a long time series from many satellite instruments. Melting ice sheets, thermal expansion of water, and terrestrial freshwater use are just some of the major factors contributing to rising sea levels. For example, international satellites have collected almost 30 years of data on sea surface height from satellite altimeters.īut no single satellite instrument can provide a complete picture of the status and drivers of rising seas around the world. Scientists now have an unprecedented understanding of changing sea levels, thanks to data collected and distributed by NASA and partner space agencies. Rising seas are already having catastrophic effects in coastal communities through flooding, erosion, and storm-related hazards. Sea levels are rising at an average of 3.3 millimeters per year around the world. ![]() Credit: NASA Physical Oceanography Distributed Active Archive Center (PO.DAAC). Satellite sea level observations from 1993 to present.
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