The NASA-SSH project produces value-added sea-level products for the broader scientific and operational communities.
The objective of the NASA-SSH project is to develop a coherent and consistent time series of Sea Surface Height (SSH) from multi-mission altimeter data that meets the most stringent accuracy requirements demanded to provide credible mean sea level estimates for climate research. The development of the different NASA-SSH products is a collaborative effort between JPL, NASA/GSFC, University of South Florida, University of Colorado, and the NOAA Laboratory for Satellite Altimetry.
Currently the along track Sea Surface Height (SSH) data are available for the successive reference missions (TOPEX/Poseidon (T/P), Jason-1, Ocean Surface Topography Mission/Jason-2 (OSTM) and Jason-3, and Sentinel-6 Michael Freilich) from September 1992 to the present. In the upcoming months, coherent along-track datasets will also be provided for high-latitude past and current altimetry missions.
The NASA-SSH 0.5-degree latitude-longitude grids are currently computed from the NASA-SSH along-track reference missions data.
These grids are in turn used to estimate a suite of SSH-based climates indicators (global mean sea level (GMSL), El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Pacific Decadal Oscillation (PDO)).
The NASA-SSH project comes from an effort to produce coherent and consistent time series of Sea Surface Height (SSH) across different altimetry missions. The measurement of geocentric Mean Sea Level (MSL) change from satellite altimetry requires an extreme stability of the altimeter measurement system since the signal being measured is at the level of a few mm/yr. This means that the orbit and reference frame within which the altimeter measurements are situated, the quality control, and the associated altimeter corrections (including the wet troposphere, ocean tides, pole tide, and dry troposphere corrections as well as intermission biases and sea state bias) must be stable, coherent, and accurate enough to permit a robust MSL estimate. Foremost, orbit quality and consistency are critical not only to satellite altimeter measurement accuracy across one mission, but also for the seamless transition between missions.
Maintenance and improvements to the fidelity of the SSH record is continuous through the research activities of the Ocean Surface Topography Science Team (OSTST). As further advancements and/or re-calibrations are made to any of the correction parameters or models, the SSH time series is recalculated and updated with the most accurate algorithms sanctioned by the OSTST. Notification and details of revisions will be provided at this site.
NASA-SSH V1 User Guide (.pdf)
User Note: The NASA-SSH along track data, NASA –SSH simple grids, and NASA-SSH indicators are updated weekly.
