Assessment of simulations of a polar low with the Canadian Regional Climate Model

(Fig 10B). In general, the RMSE of the simulations significantly increases from around 1000 UTC until some time between 1400 UTC and 1800 UTC, and then decreases (not shown). The Spearman correlation coefficient varies widely between simulations from 1000 UTC until 1300 UTC, and then it converges to values mostly between 0.4 and 0.6 (not shown). ERA5 shows better skill at representing the dew point temperature than the simulations. In effect, the reanalysis has the lowest mean error (1.1˚C), the lowest RMSE (2.1˚C), and the high- est Spearman correlation coefficient (0.73), indicating quite strong correlation with the obser- vations (Table 4). The ME (Fig 10B) and the RMSE (not shown) of ERA5 decrease from around 1300 UTC until the PL has dissipated. During the last seven hours of the lifetime of the Fig 10. Time series of the ME of the simulated and ERA5 (a) 2-m temperature, (b) 2-m dewpoint temperature and (c) 2-m relative humidity. The datasets used as reference to compute the ME are the observations at surface stations. https://doi.org/10.1371/journal.pone.0292250.g010 PLOS ONE Assessment of simulations of a polar low with the canadian regional climate model PLOS ONE | https://doi.org/10.1371/journal.pone.0292250 October 5, 2023 16 / 28