MAE stands for Mean Absolute Error. You can read more about MAE here.
If, for example, the true wind speed MAE is 2.6, this value is measured in knots and is the average difference between the forecast model and the dedicated observations station.
You can see which observation station is being used on the map; the intersection of the red lines is the station's approximate location.
We have separated each calculation into Wind Speed and Wind Direction.
MAE Wind Speed is the Mean Absolute Error of the True Wind Speed and measured in knots
MAE Wind Direction is the Mean Absolute Error of the True Wind Direction and measured in the compass degrees