Meteorological or Mathematical Wind Direction

Hi all,

I am going to use the ERA5-Land reanalysis wind data (U & V components) for my research. So, I downloaded them and tried to extract the wind speed and direction using the structure in the ERA5 documents as follows:

ERA5: How to calculate wind speed and wind direction from u and v components of the wind?

When I checked the link, I found that they mentioned "meteorological wind direction" but I am not sure if it is correct or not. I checked the following website and found that there are two wind directions, 1) meteorological direction from the synoptic or raw observations and 2) mathematical direction from the global datasets. So, could you please let me know which type of direction we will get by calculating the direction from ERA5-land datasets?

To convert from "meteorological direction" to "math direction", use use this formula (in degrees):

    md = 270 − wwd

where md is the "mathematical direction", and wwd is the "meteorological direction".