Global average sea level rise indicator (NASA)
What it measures. A single running number through time: how much the world's average sea level has risen or fallen, in centimeters.
How it's made. Calculated by averaging satellite radar measurements of sea surface height from a series of reference altimeter missions like TOPEX/Poseidon, Jason, and Sentinel-6.
How & where you'd use it. A go-to indicator for tracking global sea level rise over the decades; note it has not been adjusted for the slow sinking of the sea floor, which matters for detailed budget studies.
What's measured
Coverage & cadence
- Time span1993-01-04 → ongoing
- Measured byTOPEX/POSEIDON (SSALT, NRA, TMR) · JASON-1 (POSEIDON-2, JASON-1 Microwave Radiometer) · OSTM/JASON-2 (POSEIDON-3, AMR) · JASON-3 (POSEIDON-3B, AMR-2) · Sentinel-6A (Poseidon-4 Radar Altimeter, AMR-C)
- Processing levelLevel 4
- Spatial extent-180, -66, 180, 66
- FormatsASCII
- StatusACTIVE
What you can do with it
- Watch sea-surface temperature and marine heatwaves
- Spot algal blooms and ocean-colour shifts
- Support fisheries and coastal monitoring
Official description
This file contains a time series of globally-averaged sea level change, or "global mean sea level" (GMSL) in units of centimeters. The estimate is based on satellite observations of sea surface height anomaly, measured by reference radar altimeter missions such as TOPEX/Poseidon, the Jason series, and Sentinel-6. The indicator values were calculated using NASA-SSH Simple Gridded Sea Surface Height from Standardized Reference Missions Only Version 1 https://podaac.jpl.nasa.gov/dataset/NASA_SSH_REF_SIMPLE_GRID_V1 . GMSL was calculated as the area-weighted average over each map in the time series of Simple Gridded Sea Surface Height. Because maps are computed using 10-days of observations, but are computed once every 7 days, there is a small amount of overlap between data used to compute successive time steps. A version of the estimate smoothed over 60 days is also provided. Expert users, please note that this estimate has NOT been adjusted for Glacial Isostatic Adjustment, to account for the slight long-term depression of the sea floor. Users who study the sea level budget will need to account for this effect in order to properly evaluate closure of the budget. Note that occasional improvements to data quality can result in mm level change in the historical portions of this estimate. However, such changes remain small relative to the 3-5 mm uncertainty in global sea level estimates over the course of the 30+ year record (https://essd.copernicus.org/articles/11/1189/2019/) The file with the filename "NASA_SSH_GMSL_INDICATOR.txt" is always the most up-to-date time series containing the most recent data.
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="NASA_SSH_GMSL_INDICATOR",
version="1",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from POCLOUD Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package. Official links
- Search Granules GET DATA
- Browse Granule Listing GET DATA
- User Guide VIEW RELATED INFORMATION
- PO.DAAC Forum Page VIEW RELATED INFORMATION
- NASA-SSH Project Landing Page VIEW RELATED INFORMATION
- Data Use and Citation Guidelines VIEW RELATED INFORMATION
- This dataset can be downloaded using the podaac-data-subscriber (the recommended tool for bulk downloading PO.DAAC data). It is a Python package for downloading one or many files using the command line interface. The URL redirects to the data-subscriber home page with instructions for utilizing the tool GET DATA