Canadian RCM projected changes to short‐ and long‐term drought characteristics over the Canadian Prairies

Abstract

ABSTRACT:The Canadian Prairies have experienced severe and extended droughts that have had significant impacts on agriculture, energy and other socio-economic sectors; it is therefore desirable to assess future changes to drought characteristics in this drought prone region, in the context of a changing climate. This study addresses validation and projected changes to short-and long-term drought characteristics, i.e. severity, frequency and duration, over the Canadian Prairies, using an ensemble of ten Canadian RCM (CRCM) simulations, of which five correspond to the current 1971-2000 period and the other five are the matching simulations for the future 2041-2070 period. These five pairs of current and future CRCM simulations were driven by five different members of a Canadian Global Climate Model ensemble. Validation of CRCM simulated precipitation suggests that the model reproduces the observed precipitation distribution for all seasons, except summer, across a large portion of the Canadian Prairies. However, comparison of CRCM simulated drought characteristics with those observed suggests that the model has difficulties in reproducing observed severity, frequency and duration of drought events, particularly those associated with longer events, possibly due to the overestimation of summer precipitation by the model. Analysis of projected changes to precipitation and drought characteristics between the 1971-2000 and 2041-2070 periods suggests a decrease in mean precipitation in summer and an increase for the other seasons, while the severity, frequency and maximum duration of both short-and long-term droughts are projected to increase over the southern Prairies, with the largest projected changes associated with longer drought events. Classification of the watersheds spanning the southern Prairies based on changes to both severity and frequency further reveal the vulnerability of this region in a changing climate.

A framework for investigating large-scale patterns as an alternative to precipitation for downscaling to local drought

“…CESM-LE is a 30-member ensemble, run under the Representative Concentration Pathway 8.5 (RCP 8.5) to the year 2080. In this study we assume that the model bias is stationary in time (Buonomo et al 2007;Done et al 2013;PaiMazumder et al 2013;PaiMazumder and Done 2014). We examine changes to PDSI by looking at future anomalies, i.e., we calculate each ensemble member's mean PDSI for the control period and subtract that from each member.…”

“…their own climate. Because of their smaller domain and higher resolution, RCMs can resolve finer scale physical processes and enhance the representation of land surface characteristics, leading to improved simulation of smaller scales (Dickinson et al 1989;Giorgi et al 1994;Wang et al 2004;Lo et al 2008;Heikkila et al 2010;Maraun et al 2010;Qian et al 2009;PaiMazumder et al 2013;Harding et al 2013). However, these dynamical models remain expensive and therefore limited in their use, especially in terms of running ensembles to make an assessment of the uncertainty from internal variability at local scales.…”

Climate change and water resources: a case study of the canadian prairie region

“…The Intergovernmental Panel on Climate Change [10] has concluded that climate change has begun to affect the frequency, intensity and duration of extreme events such as extreme temperatures, extreme precipitation, droughts, etc. For Southern Prairies, an analysis of projected changes to precipitation and drought characteristics between the1971-2000 and 2041-2070 periods suggests a decrease in mean precipitation in summer and an increase for the other seasons, whereas the severity, frequency and maximum duration of both short-and long-term droughts are projected to increase, with the largest projected changes associated with longer drought events [11].…”

Climate and water availability indicators in Canada: Challenges and a way forward. Part III – Future scenarios

“…Drought severity for 3-month (DRO3), 6-month (DRO6) and 10-month (DRO10) durations for the Canadian Prairies were simulated with the CRCM for the A2 scenario, 2041-2070 period (PaiMazumder et al 2012). These are based on drought severity indices obtained from accumulated monthly precipitation deficits, using 1971-2000 reference climatology.…”