<p>The simple answer is that you just subtract the nearest value from the glacial isostatic adjustment (GIA) model. The values provided by <a href="http://www.atmosp.physics.utoronto.ca/~peltier/data.php" rel="nofollow noreferrer">Peltier</a> in your netCDF file are in a grid that is 1 degree x 1 degree. So with the lat/lon position from the tidal gauge sea level data, you choose the closest value to your station and apply the correction. In the <a href="http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/?" rel="nofollow noreferrer">PSMSL GIA correction page</a> they already explain that you should be using the centered value (±250 years). If you decide to use the ASCII files, those are already interpolated to the tide gauge station locations. You have additional information in the U. of Colorado GIA websites(<a href="http://sealevel.colorado.edu/content/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it" rel="nofollow noreferrer">1</a>, <a href="http://sealevel.colorado.edu/content/gia-faq-updated-peltier-reference" rel="nofollow noreferrer">2</a>) and in the <a href="http://dx.doi.org/10.1016/S0074-6142(01)80007-3" rel="nofollow noreferrer">Peltier (2001) reference</a>.</p>

CC BY-SA 3.0
2016-09-20T14:30:29.677Z
Thank you for answering that. I have read numerous papers in the last couple of days including references and explanations on the indicated PSMSL page. It is not GIA itself I do not understand, but the way scientists are correcting data. I already thought about subtracting the value, but I was thinking that maybe there is a more complicated method. Guess sometimes the simple answer is actually the correct one.
crisvr
CC BY-SA 4.0
2016-09-20T13:23:30.353Z
2019-05-06T13:58:57.917Z
2019-05-06T13:58:57.917Z
arkaia
<p>I have a <a href="http://www.psmsl.org" rel="nofollow">PSMSL</a> <a href="http://www.psmsl.org/data/obtaining/rlr.php" rel="nofollow">RLR (revised local reference)</a> sea level dataset with records from various tide gauges. Can anyone explain how to correct them for GIA (glacial isostatic adjustment) using the ICE-5G model from <a href="http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/?" rel="nofollow">here</a>.</p>

<p>I have a netCDF version with 4 components and some ASCII files. </p>

<geophysics><oceanography><sea-level><tides><netcdf>
How to correct PSMSL data for GIA?
crisvr
# How to correct PSMSL data for GIA?

(Asked by: username_0 on 2016-09-20)

I have a [PSMSL](http://www.psmsl.org) [RLR (revised local reference)](http://www.psmsl.org/data/obtaining/rlr.php) sea level dataset with records from various tide gauges. Can anyone explain how to correct them for GIA (glacial isostatic adjustment) using the ICE-5G model from [here](http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/?).

I have a netCDF version with 4 components and some ASCII files.

**Tags:** geophysics, oceanography, sea-level, tides, netcdf


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## 1 answers

### Answer by username_1 on 2016-09-20. Score: 2

The simple answer is that you just subtract the nearest value from the glacial isostatic adjustment (GIA) model. The values provided by [Peltier](http://www.atmosp.physics.utoronto.ca/~peltier/data.php) in your netCDF file are in a grid that is 1 degree x 1 degree. So with the lat/lon position from the tidal gauge sea level data, you choose the closest value to your station and apply the correction. In the [PSMSL GIA correction page](http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/?) they already explain that you should be using the centered value (±250 years). If you decide to use the ASCII files, those are already interpolated to the tide gauge station locations. You have additional information in the U. of Colorado GIA websites([1](http://sealevel.colorado.edu/content/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it), [2](http://sealevel.colorado.edu/content/gia-faq-updated-peltier-reference)) and in the [Peltier (2001) reference](http://dx.doi.org/10.1016/S0074-6142(01)80007-3).

> **Comments:**
> **username_0**: Thank you for answering that. I have read numerous papers in the last couple of days including references and explanations on the indicated PSMSL page. It is not GIA itself I do not understand, but the way scientists are correcting data. I already thought about subtracting the value, but I was thinking that maybe there is a more complicated method. Guess sometimes the simple answer is actually the correct one.  

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