![enter image description here][1]
Figure 5.1 Impact of the model resolution on the 10-m maximum wind speed baseline conditions defined as the median and root-mean-square (RMS) – for the ensemble of the 22 bora events, of the difference (or bias) between ERA5, WRF 15-km, WRF 1.5-km and WRF 3-km model results.
For the 10-m maximum wind speed, the baseline conditions (WRF 3-km) are spatially compared with WRF 15-km, WRF 1.5-km and ERA5 median biases and variabilities – i.e. median and root-mean-square derived, for the ensemble of 22 events, from the differences (i.e. biases) between each model separately and WRF 3-km. Although being based on numerical results, this comparison clearly highlights that the ERA5 model homogeneously underestimates by up to 20 m/s (with a variability of 15 m/s in average) the extreme bora winds along the Velebit mountain range and over the Kvarner Bay while biases for the WRF 15-km and WRF 1.5-km models are extremely localized and inhomogeneous (i.e. positive and negative biases are mostly found on opposite sides of the mountain ridges) and only reach up to +/- 5 m/s (with a maximum variability of 8 m/s) for WRF 15-km and +/- 1.5 m/s (with a maximum variability of 5 m/s) for WRF 1.5-km. These results show that the ERA5 model is largely underestimating the strength of the extreme bora events in the northern Adriatic region.
[1]: https://files.osf.io/v1/resources/u62ey/providers/osfstorage/5ec4e143c7d4ab009d21d922?mode=render