Mean storm occurrence over North America as simulated by CRCM5

A storm track algorithm based on tracking approach developed by Sinclair et al. (1997) is used to retrieve individual extratropical cyclone over the current period (North America domain) from meteorological fields of the North America Regional Reanalysis (NARR), the Canadian Regional Climate Model version 5 (CRCM5) driven by global reanalysis ERA-interim and the Canadian Earth System Model version 2 (CanESM2). The CRCM5 storm occurrences are compared with the ones from NARR reanalysis and the CanESM2. All models and reanalysis reproduce the main know storm tracks corridors over North Canada and the western North Atlantic during fall and winter months (see Figure 1). However, CanESM2 global model strongly overestimates the number of storms over the Eastern Atlantic coastlines (by around 30%) compared to NARR data (Figure 1), whereas the CRCM5 simulation is quite similar to NARR products.

Figure 1: Mean storm occurrence (storm month-1) from November to March period (NDJFM) over North America from a) NARR reanalysis products, b) CRCM5 simulation driven by ERA-Interim, and c) CanESM2 simulation. The mean values are computed over the1981-2010 period for NARR and CRCM5, and over the 1970-2000 period for CanESM2.

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