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

Marta Moreno-Ibáñez; René Laprise; Philippe Gachon

doi:10.1371/journal.pone.0292250

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

PLoS One. 2023 Oct 5;18(10):e0292250. doi: 10.1371/journal.pone.0292250. eCollection 2023.

Authors

Marta Moreno-Ibáñez^{1

2}, René Laprise^{1

2}, Philippe Gachon^{1

3}

Affiliations

¹ Centre for the Study and Simulation of Regional-Scale Climate (ESCER), University of Quebec in Montreal (UQAM), Montreal, Canada.
² Department of Earth and Atmospheric Sciences, University of Quebec in Montreal (UQAM), Montreal, Canada.
³ Department of Geography, University of Quebec in Montreal (UQAM), Montreal, Canada.

Abstract

Polar lows (PLs), which are intense maritime polar mesoscale cyclones, are associated with severe weather conditions. Due to their small size and rapid development, PL forecasting remains a challenge. Convection-permitting models are adequate to forecast PLs since, compared to coarser models, they provide a better representation of convection as well as surface and near-surface processes. A PL that formed over the Norwegian Sea on 25 March 2019 was simulated using the convection-permitting Canadian Regional Climate Model version 6 (CRCM6/GEM4, using a grid mesh of 2.5 km) driven by the reanalysis ERA5. The objectives of this study were to quantify the impact of the initial conditions on the simulation of the PL, and to assess the skill of the CRCM6/GEM4 at reproducing the PL. The results show that the skill of the CRCM6/GEM4 at reproducing the PL strongly depends on the initial conditions. Although in all simulations the synoptic environment is favourable for PL development, with a strong low-level temperature gradient and an upper-level through, only the low-level atmospheric fields of three of the simulations lead to PL development through baroclinic instability. The two simulations that best captured the PL represent a PL deeper than the observed one, and they show higher temperature mean bias compared to the other simulations, indicating that the ocean surface fluxes may be too strong. In general, ERA5 has more skill than the simulations at reproducing the observed PL, but the CRCM6/GEM4 simulation with initialisation time closer to the genesis time of the PL reproduces quite well small scale features as low-level baroclinic instability during the PL development phase.

Copyright: © 2023 Moreno-Ibáñez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Canada
Climate
Climate Models*
Computer Simulation
Models, Theoretical*

Grants and funding

This work was supported by the Discovery Grant program of the Natural Sciences and Engineering Research Council of Canada (NSERC) under Grant 707337, by the project “Marine Environmental Observation, Prediction and Response” (MEOPAR) of the Networks of Centres of Excellence (NCE) of Canada, by the UQAM’s Faculty of Sciences under the programme “faculty financial support”, and by the excellence scholarship of the Trottier Family Foundation. The operation of the supercomputer Beluga is funded by the Canada Foundation for Innovation (CFI), Ministère de l’Économie et de l’Innovation du Québec (MEI) and les Fonds de recherche du Québec (FRQ). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study.