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

3.4 Final discussion To understand why only 24d12h and 24d18h correctly capture the development of the PL, it is necessary to analyse the simulated atmospheric fields from a few hours before its formation until its genesis time. It is assumed that, during this period, the synoptic conditions are favour- able for PL formation in 24d12h and 24d18h, but not in the other simulations. Fig 12 shows the SLP, the geopotential height at 500 hPa and the 1000-500 hPa thickness on 25 March at 0000 UTC. There is a 500-hPa through with a northeast-southwest orientation in all simulations. Although its shape is slightly different in the simulations, the through is in the Fig 12. Simulated and ERA5 fields showing the PL on 25 March 2019 at 0000 UTC. The colourmap represents the 1000-500 hPa thickness (dam), the black isobars represent the SLP (hPa, contours every 2 hPa) and the red dashed lines represent the geopotential height at 500 hPa (dam, contours every 2 dam). The black outlining represents the coastline, and the white dashed line represents the sea ice edge, which is defined as the 0.15 contour of the sea ice concentration. ERA5 fields have been interpolated to the grid of the simulation using bicubic interpolation for the SLP, 1000-500 hPa thickness, and geopotential height, and bilinear interpolation for the sea ice concentration. The sea ice edge in ERA5 corresponds to the 25 March 2019 at 1200 UTC. The dataset used to plot the geographic contours has been obtained from the GSHHG [33] under a CC BY license, with permission from Dr. Paul Wessel.

https://doi.org/10.1371/journal.pone.0292250.g012 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 21 / 28