Associated with global warming resulting from anthropogenic emissions of greenhouse gases and aerosols (GHGA), changes in temperature extremes and increases in intense precipitation events are amongst the more robust climate-change signals in the observed weather records, as well as in model projections for the future (Kharin et al., 2007, 2012; Seneviratne et al., 2012). Questions about extremes are highly topical both scientifically and from an impacts perspective. Intense precipitation events and temperature extremes have substantial impacts on ecosystems, infrastructure, and the health and safety of Canadians. Climate models such as GCMs and RCMs are the primary tools used to study anticipated climate changes associated with specific time-evolving emissions scenarios for anthropogenic GHGA. The coarse spatial resolution of GCMs does not adequately represent mesoscale processes and fine scale topographic features, which is a severe limitation for impact and adaptation studies. The higher spatial resolution of RCMs, compared to GCMs, allows for greater realism of physiographic forcing and finer-scale atmospheric dynamics; they thereby represent a potentially more suitable tool for adequately simulating processes responsible for precipitation and temperature extremes as required for regional impact and adaptation studies.
This theme will document the ability of high-resolution RCMs to simulate extreme temperature and precipitation events, and their links to circulation variations and land-atmosphere coupling, both incurrent and future climates. The analysis will make full use of standard extreme indices and statistical extreme value theory.