I have two wind data sets that I want to compare:

  • a) Aircraft derived data (ADS-B and Mode-S).
  • b) ERA5 Reanalysis data. To compare both I need altitudes to be comparable. On data set a) I have the geometric height. Precisely, it corresponds to Data Item from I021/140 from ICAO document Part 12: Category 021, as seen in the following image:

enter image description here

On the other hand, data set b) is given in "pressure levels". What I did is to transform this pressure level on b) to altitude using the ISA model. Then I supposed I can compare this altitude with the geometric height given on a). But I am not sure if it's correct to do so. I don't know if the pressure level on ERA5 is just a way to indicate altitudes or not.

Is it correct? If not, is there any way to compare them?


New contributor
Marius Marinescu is a new contributor to this site. Take care in asking for clarification, commenting, and answering. Check out our Code of Conduct.
  • $\begingroup$ Related What is the geoid undulation used for in aviation? I think you need to add the geoid undulation N to the altitude obtained from the ISA model, to get the ellipsoidal height comparable with ADS-B data. Still you'll be comparing a barometric altitude (not an actual altitude) with a GPS altitude. $\endgroup$
    – mins
    Oct 12 at 23:33

Your Answer

Marius Marinescu is a new contributor. Be nice, and check out our Code of Conduct.

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.