DOI: 10.5281/zenodo.12701797
title: Global Mean Sea Level, Trajectory and Extrapolation

description: Global Mean Sea Level, Trajectory and Extrapolation

This file contains Global Mean Sea Level (GMSL) variations along, data for the quadratic fit (trajectory) to the GMSL variations, and an extrapolation of this trajectory to 2050. 

The GMSL variations(column 2) are 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_V51). It combines Sea Surface Heights from the TOPEX/Poseidon, Jason-1, OSTM/Jason-2, Jason-3, and Sentinel-6 Michael Freilich missions.

In addition, the rate and acceleration are estimated from full record of GMSL relative to the midpoint of the record and then used to generate a quadratic fit to the data. This quadratic fit is provided in column 3. The rate associated with this quadratic fit at any time in the record is also provided (column 4). 

The parameters estimated from the quadratic fit are also used to generated an extrapolated time series out to 2050 (column 5). These are provided at yearly intervals. This is not a projection and is only considered an extrapolation of the current trajectory of GMSL variations. This also differs from Nerem et al. (2022) and Sweet et al. (2022) as additional signals are not removed from GMSL prior to estimating the rate and acceleration parameters. The yearly rate associated with this extrapolation is also provided (column 6)If you use these data please cite:Willis, J.K., Hamlington, B.D., and Fournier, S., Global Mean Sea Level Time Series, Trajectory and Extrapolation. Dataset access [YYYY-MM-DD] at 10.5281/zenodo.7702315.GSFC. 2021. Global Mean Sea Level Trend from Integrated Multi-Mission Ocean Altimeters TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 Version 5.1. Ver. 5.1 PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/GMSLM-TJ151.

***Users of the 2024 release of this product should note that several updates were made since the previous release to improve the accuracy of the record.  These include newly reprocessed data for the TOPEX/Poseidon satellite, primarily affecting the first decade of the record, as well as corrections of small errors in more recent missions like Jason-2 and Jason-3, primarily affecting data after 2010.  Changes to the estimate of global mean sea level were on the order of a few mm, in both the early and late parts of the record.  These changes improved agreement between the satellite altimeters and independent observations from tide gauges and other types satellites.The net effect of the changes was to slightly reduce the total amount of rise by about 3/4 of a centimeter during the 30 year record.  However, the  acceleration of the rate of global rise was almost unchanged, with the rate getting faster by about 0.8 mm/year, each decade.For more details on the changes, please see the relevant sections of the 2022 and 2023 yearly reports from the Ocean Surface Topography Science Team:https://www.aviso.altimetry.fr/fileadmin/documents/OSTST/2022/OSTST_2022_Meeting_Report.pdfhttps://www.aviso.altimetry.fr/fileadmin/documents/OSTST/2023/OSTST_2023_Meeting_Report.pdf

 

References:

Nerem, R. S., Frederikse, T., & Hamlington, B. D. (2022). Extrapolating Empirical Models of Satellite‐Observed Global Mean Sea Level to Estimate Future Sea Level Change. Earth's Future, 10(4), e2021EF002290.

Sweet, W. V., Hamlington, B. D., Kopp, R. E., Weaver, C. P., Barnard, P. L., Bekaert, D., ... & Zuzak, C. (2022). Global and regional sea level rise scenarios for the United States: updated mean projections and extreme water level probabilities along US coastlines. Interagency Technical Report.