<p>The height coordinate varies and is described for the various variables on the site you link.  For example:</p>

<blockquote>
  <p>Levels:</p>
  
  <p>Surface or near the surface (.995 sigma level), or entire atmosphere (eatm)</p>
</blockquote>

<p>and</p>

<blockquote>
  <p>Levels:</p>
  
  <p>17 Pressure levels (mb): 1000,925,850,700,600,500,400,300,250,200,150,100,70,50,30,20,10
  Some variables have less: omega (to 100mb) and Humidities (to 300mb).</p>
</blockquote>

<p>For the pressure levels coordinate the height above the ground is variable and dependent on atmospheric conditions.  The sigma levels are terrain following and flatten out with height and will vary with local topography. (see <a href="http://www.met.tamu.edu/class/metr452/models/2001/vertres.html" rel="nofollow">this for more info</a>)</p>

<p>You can estimate height using the <a href="https://en.wikipedia.org/wiki/Hypsometric_equation" rel="nofollow">hypsometric equation</a>, or use the geopotential field from the data to determine the height at specific grid locations (it will vary horizontally).  For processing, I would recommend using the geopotential data since it is available for each of the vertical coordinate possibilities in this dataset.</p>

CC BY-SA 3.0
2015-08-21T23:03:01.977Z
2015-08-21T23:08:52.000Z
2015-08-21T23:08:52.000Z
casey
<p>I am confused regarding the height above ground of this data set. <a href="http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html">http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html</a></p>

<p>I have to reprocess this data set and need to know this piece of information.</p>

CC BY-SA 3.0
2015-08-21T18:52:18.747Z
Have you looked here (http://rda.ucar.edu/datasets/ds090.0/docs/publications/bams1996mar/bams1996mar.pdf)?
Isopycnal Oscillation
<atmosphere><atmosphere-modelling><ncep><reanalysis>
What is the height above ground of NCEP/NCAR Reanalysis 1 variables?
Herman Toothrot
# What is the height above ground of NCEP/NCAR Reanalysis 1 variables?

(Asked by: username_0 on 2015-08-21)

I am confused regarding the height above ground of this data set. <http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html>

I have to reprocess this data set and need to know this piece of information.

**Tags:** atmosphere, atmosphere-modelling, ncep, reanalysis

> **Comments:**
> **username_1**: Have you looked here (http://rda.ucar.edu/datasets/ds090.0/docs/publications/bams1996mar/bams1996mar.pdf)?  

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## 1 answers

### Answer by username_2 on 2015-08-21. Score: 3 | Accepted answer

The height coordinate varies and is described for the various variables on the site you link. For example:

> Levels:
>
> Surface or near the surface (.995 sigma level), or entire atmosphere (eatm)

and

> Levels:
>
> 17 Pressure levels (mb): 1000,925,850,700,600,500,400,300,250,200,150,100,70,50,30,20,10
> Some variables have less: omega (to 100mb) and Humidities (to 300mb).

For the pressure levels coordinate the height above the ground is variable and dependent on atmospheric conditions. The sigma levels are terrain following and flatten out with height and will vary with local topography. (see [this for more info](http://www.met.tamu.edu/class/metr452/models/2001/vertres.html))

You can estimate height using the [hypsometric equation](https://en.wikipedia.org/wiki/Hypsometric_equation), or use the geopotential field from the data to determine the height at specific grid locations (it will vary horizontally). For processing, I would recommend using the geopotential data since it is available for each of the vertical coordinate possibilities in this dataset.


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