AMET v1.4: RMSE of Wind Direction

Hello,

While viewing the MET example on the official AMET github website, I found a strange discrepancy in the range of wind directions from the output of the “run_summary.csh” script.

In particular, according to the “Example csv” file of diurnal and overall statistics (https://github.com/USEPA/AMET/blob/master/docs/images/stats.metExample_wrf.JULY2016.csv), the range of wind directions is [2.887e-11, 9.999e-4] for the METAR observational data and [-179.999, 179.994] for the WRF model data. This in turn results in a very high RMSE value of 49.7.

Does anyone know why this is the case? Is there a typical / acceptable range for the RMSE (or the other model performance summary statistics) of wind direction? In a separate analysis using different WRF data, I get a wind direction RMSE value of about 90.

Any assistance would be greatly appreciated,
Rowena