Since 1993, measurements from the TOPEX and Jason series of satellite radar altimeters have allowed estimates of global mean sea level. These measurements are continuously calibrated against a network of tide gauges. When seasonal and other variations are subtracted, they allow estimation of the global mean sea level rate. As new data, models and corrections become available, we continuously revise these estimates (about every two months) to improve their quality.

2014_rel5: Global Mean Sea Level Time Series (seasonal signals removed)

Edited: 2014-11-04

Data

Raw data (ASCII) | PDF | EPS

Similar plots

Global Mean Sea Level Time Series (seasonal signals retained)

Release Notes

2014 Release 5 (2014-11-04):

  • Added Jason-2/OSTM GDR cycles 210-226.

Instrument Drift Monitoring

To cite these plots or data, please use:  Nerem, R. S., D. Chambers, C. Choe, and G. T. Mitchum. "Estimating Mean Sea Level Change from the TOPEX and Jason Altimeter Missions." Marine Geodesy 33, no. 1 supp 1 (2010): 435.

2014_rel4: GMSL and Multivariate ENSO Index

Edited: 2014-05-29

PDF | EPS

Discussion

The Multivariate ENSO Index (MEI) is the unrotated, first principal component of six observables measured over the tropical Pacific (see NOAA ESRL MEI, Wolter & Timlin, 1993,1998).  To compare the global mean sea level to the MEI time series, we removed the mean, linear trend, and seasonal signals from the 60-day smoothed global mean sea level estimates and normalized each time series by its standard deviation. The normalized values plotted above show a strong correlation between the global mean sea level and the MEI, with the global mean sea level often lagging changes in the MEI.

Correction: New GMSL release and Jason-2 Switch to Side-B Platform Module

Edited: 2013-08-29

In this previous blog post, we incorrectly stated that Jason-2 had switched to the side B altimeter. In fact, only the processing chain (also known as the Platform Module) had switched to side B hardware. The actual altimeter instrument is still on side A.

As our FAQ states, we release new GMSL estimates as the Jason-2 GDR products are produced upstream by the French processing center AVISO. Cycles 170-172 were released by AVISO on May 9-10, and we released 2013_rel4 of our GMSL time series on May 15. Jason-2 did have two recent safe-hold periods during cycles 174 and 175, and these cycles will have impacted data. After the second safe-hold, Jason-2 automatically switched to its redundnat Platform Module-B. The operations team decided to leave Jason-2 operating on Platform Module-B, and no adverse effects have yet been noted to the science data.

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