Global Mean Sea Level Data

Temporal Coverage: September 1992 - September 2024

This file contains Global Mean Sea Level (GMSL) variations computed at the NASA Goddard Space Flight Center under the
auspices of the NASA Sea Level Change program. The GMSL was generated using the Integrated Multi-Mission Ocean Altimeter Data for
Climate Research (http://podaac.jpl.nasa.gov/dataset/MERGED_TP_J1_OSTM_OST_ALL_V52). It combines Sea Surface Heights from the
TOPEX/Poseidon, Jason-1, OSTM/Jason-2, Jason-3, and Sentinel-6 Michael Freilich missions to a common terrestrial reference frame with all inter-mission biases, range and
geophysical corrections applied and placed onto a georeferenced orbit. This creates a consistent data record throughout
time, regardless of the instrument used. Note, the most recent estimates of GMSL (post March 28, 2022) derived from the Sentinel-6 Michael Freilich mission
are preliminary as validation and reprocessing procedures for Sentinel-6 are ongoing.

For information on how the data were generate please refer to:

• Beckley, B. D., Callahan, P. S., Hancock, D. W., Mitchum, G. T., & Ray, R. D. (2017). On the 'cal-mode'
  correction to TOPEX satellite altimetry and its effect on the global mean sea level time series.
  Journal of Geophysical Research: Oceans, 122. https://doi.org/10.1002/2017JC013090
• Beckley, B.D., N. P. Zelensky, S. A. Holmes, F. G. Lemoine, R. D. Ray, G. T. Mitchum, S. D. Desai & S. T. Brown, Assessment
  of the Jason-2 Extension to the TOPEX/Poseidon, Jason-1 Sea-Surface Height Time Series for Global Mean Sea Level
  Monitoring, Marine Geodesy, Vol 33, Suppl 1, 2010. DOI:10.1080/01490419.2010.491029

Columns Description

Global Mean Sea Level (GMSL) variations from TPJAOS v5.1

1. altimeter type 0=dual-frequency 999=single frequency (ie Poseidon-1)
2. merged file cycle #
3. year+fraction of year (mid-cycle)
4. number of observations
5. number of weighted observations
6. GMSL (Global Isostatic Adjustment (GIA) not applied) variation (mm) with respect to 20-year TOPEX/Jason collinear mean reference
7. standard deviation of GMSL (GIA not applied) variation estimate (mm)
8. smoothed (60-day Gaussian type filter) GMSL (GIA not applied) variation (mm)
9. GMSL (Global Isostatic Adjustment (GIA) applied) variation (mm) with respect to 20-year TOPEX/Jason collinear mean reference
10. standard deviation of GMSL (GIA applied) variation estimate (mm)
11. smoothed (60-day Gaussian type filter) GMSL (GIA applied) variation (mm)
12. smoothed (60-day Gaussian type filter) GMSL (GIA applied) variation (mm); annual and semi-annual signal removed
13. smoothed (60-day Gaussian type filter) GMSL (GIA not applied) variation (mm); annual and semi-annual signal removed

Missing or bad value flag: 99900.000

TOPEX/Jason 1996-2016 collinear mean reference derived from cycles 121 to 858.

Acknowledgments

GSFC. 2024. Global Mean Sea Level Trend from Integrated Multi-Mission Ocean Altimeters TOPEX/Poseidon, Jason-1, OSTM/Jason-2, Jason-3, and Sentinel-6A Version 5.2. Ver. 5.2 PO.DAAC, CA, USA. Dataset accessed [2024-12-19] at https://doi.org/10.5067/GMSLM-TJ152.

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