No MSG5 detected

[mwasserstein]

When using pyart.io.read for several radar files, I occasionally get the error message No MSG5 detected. Setting to meaningless data. Rethink your life choices and be ready for errors.Specifically fixed angle data will be missing. I'm wondering what exactly this message means. Could this mean that I downloaded the data incorrectly? Or is it a faulty file with data that I cannot use? And would there be any way to get around this error? Thanks for your help!

[jrobrien91]

Hi Michael, do you have an example radar file that results in this error?

[mwasserstein]

Here is one radar file that will cause the error.

KMTX20000114_052707.gz

[mgrover1]

That error comes from the NEXRAD Level 2 file reader. It means that the Volume Control Pattern (VCP) data is missing, and Py-ART cannot determine with elevation levels are present

https://github.com/ARM-DOE/pyart/blob/f923551e1fd8de72c8db6c76e6bc9913bf635644/pyart/io/nexrad_level2.py#L168#L171

You can read in the file, but it is missing important metadata which may limit your analysis.

[mgrover1]

I am not sure - is it most of the files?

[mgrover1]

I would recommend reaching out to NOAA about this data quality issue. Py-ART reads in what it can (with a warning that it can't obtain the metadata since it's not there). You should be able to still work with the files, but be cautioned that you will not information about the elevation scans.

[mgrover1]

Here is the email for NCEI [email protected]

[mwasserstein]

I would say it is about 15% of the files I'm working with. I will need to keep investigating this. Thanks for your help!

[dopplershift]

Old data (not sure when it started) don't contain those messages. IMO, while it's a very convenient that those VCP messages are available, a robust reader needs to handle the case when it doesn't get that information, since the files are very much not corrupt or missing anything due to transmission.