Warm and cool season reconstruction and assessment of the long‐term hydroclimatic variability of the Canadian prairie provinces through the development of the Canadian Prairies Paleo Drought Atlas

Abstract

Persistent, large‐area droughts are among the most damaging natural disasters, having major effects on agriculture, industry, forestry, human health and society, and ecosystems. In the Canadian Prairie provinces of the sub‐humid continental interior, changing climatic conditions, and shifts between periods of extreme wet and dry weather, emphasize the need for a better understanding of past and future variability of the regional hydroclimate. Using over 180 multi‐species tree‐ring chronologies, the warm (May through August) and cool (December through April) season Standardized Precipitation Evapotranspiration Index (SPEI) was reconstructed from 1400 to 2018 on a 10‐km grid spanning the Canadian Prairies. These geospatial paleo‐drought data extend back to 1200 over a smaller geographic area. Seasonal SPEI maps, comprising the newly developed Canadian Prairies Paleo Drought Atlas (CPPDA), visually represent the hydroclimatic variability across the Canadian Prairies over past centuries, including the timing, intensity, and spatial extent of major multi‐year droughts and excessive moisture events. Wavelet analysis was also examined to determine possible potential connections between hydroclimatic variables and the influence of large‐scale ocean–atmosphere oscillations (i.e., the Pacific Decadal Oscillation (PDO) and the El Niño Southern Oscillation (ENSO)).

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