RClimate Script: Global Mean Sea Level Trend by Month

This RClimate Script lets users read a NetCDF file and plot the latest satellite altimetry based global mean sea level data  from 1993 to the latest completed month. The trend chart shows NOAA’s Laboratory for Satellite Altimetry altimeter global mean sea level with the seasonal signal removed and inverted barometer.

I will add this chart to my Climate Trend update sidebar and update it each month as NOAA releases updated mean sea level data.


In this previous post,  I presented an R script and trend chart of mean sea level data obtained from the University of Colorado, Boulder (UCB) at this site. Since the UCB dataset has not been updated since August, 2009, I have been looking for a site with more recent data.

Skeptical Science recently had a guest post by Peter Hogarth discussing Visual Depictions of Sea Level Change. Peter was kind enough to give me a link to NOAA’s Laboratory for Satellite Altimetry who provide time series data files of global mean sea level.

Mean Sea Level Trends

Here’s my RClimate script chart of satellite based mean sea level trends:

The chart shows NOAA’s estimated global mean sea level from 3 satellite missions over the 1993 – 2010 period. There has been a 2.9 mm rise per year in global mean sea level, without a glacial isostatic adjustment.

RClimate Script

NOAA uses the NetCDF file format for the sea level data. R’s ncdf  package makes it quit easy to read and analyze NetCDF files. Here’s a link to a tutorial on NetCDF files to help you get started with this format if you have not used it in the past.

Here are the data and RClimate Script links:

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