Representation of Canadian Coastal Storm Activity By Commonly Used Global Reanalyses: An Update

Abstract:

Storm activity strongly influences coastal zones in both environmental/physical and socio-economical ways. Of particular concern are damages and major local impacts, including inundation and coastal erosion, that are caused by storm interaction with the ocean. Canada’s east coast is particularly influenced by winter storms which track along two favoured routes: the St. Lawrence Valley and the Eastern Seaboard, while the west coast is influenced by the North Pacific storm track and by "atmospheric river" events. Reanalysis provides an invaluable tool for studying the characteristics of storm events that are identified as causing the most severe impacts. However, the accurate depiction of storm activity using reanalysis products is not straightforward, given differences in spatial resolution and model physics. This study evaluates the representation of storm activity along the east and west Canadian coastlines by commonly used global reanalyses distributed by the National Centers for Environmental Prediction (including NCEP-1, NCEP-2, and Twentieth Century Reanalysis) and the European Centre for Medium-Range Weather Forecasts (including ERA-Interim). Reanalysis datasets are evaluated using selected stations along each coastline and pressure tendency as a proxy for storm activity. Station selection criteria considered record length (~40 years or longer), reporting frequency (daily or shorter), proximity to coastline, and a relatively uniform spatial distribution. Comparisons are made using data extracted from the reanalysis grid point that is closest to each selected station. Preliminary results for reanalysis storm activity representations (proxies calculated annually) were presented at the 2013 AGU Fall Meeting (A53B-0161). Seasonal representations (JFM, AMJ, JAS, OND, and “extended winter” ONDJFM) have since been investigated to obtain a more detailed understanding of the Canadian coastal storm activity representations by these commonly used global reanalyses.