Temporal and Spatial Changes of the Agroclimate in Alberta, Canada, from 1901 to 2002

Abstract

This paper analyzes the long-term temporal trends in the agroclimate of Alberta, Canada, and explores the spatial variations of the agroclimatic resources and the potential crop-growing area in Alberta. Nine agroclimatic parameters are investigated: May-August precipitation (PCPN), the start of growing season (SGS), the end of the growing season (EGS), the length of the growing season (LGS), the date of the last spring frost (LSF), the date of the first fall frost (FFF), the length of the frost-free period (FFP), growing degree-days (GDDs), and corn heat units (CHUs). The temporal trends in the agroclimatic parameters are analyzed by using linear regression. The significance tests of the trends are made by using Kendall's tau method. The results support the following conclusions. 1) The Alberta PCPN has increased 14% from 1901 to 2002, and the increment is the largest in the north and the northwest of Alberta, then diminishes (or even becomes negative over two small areas) in central and southern Alberta, and finally becomes large again in the southeast corner of the province. 2) No significant long-term trends are found for the SGS, EGS, and LGS. 3) An earlier LSF, a later FFF, and a longer FFP are obvious all over the province. 4) The area with sufficient CHU for corn production, calculated according to the 1973-2002 normal, has extended to the north by about 200-300 km, when compared with the 1913-32 normal, and by about 50-100 km, when compared with the 1943-72 normal; this expansion implies that the potential exists to grow crops and raise livestock in more regions of Alberta than was possible in the past. The annual total precipitation follows a similar increasing trend to that of the May-August precipitation, and the percentile analysis of precipitation attributes the increase to low-intensity events. The changes of the agroclimatic parameters imply that Alberta agriculture has benefited from the last century's climate change.

A multi‐scale hydroclimatic analysis of runoff generation in the Athabasca River, western Canada

“…The latter result is consistent with an agroclimatological study by Shen et al . (), who reported an 8% increase in May to August precipitation for Alberta over 1901 to 2002, and that the trends were not spatially uniform across the province.…”

Spatiotemporal change in China’s climatic growing season: 1955–2000

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Precipitation variability and its relationship to hydrologic variability in Alberta

“…According to Shen et al (2005), the root meansquare errors of the daily township precipitation data ranged from 1Ð8 to 2Ð8 mm and for the daily maximum and minimum air temperature 1Ð4-3Ð2°C and 1Ð8-3Ð2°C, respectively. When daily data were converted to monthly values and cross-checked for accuracy against the observed monthly data obtained from Environment Canada (Table II and Figure 4), the errors in the interpolated monthly precipitation data ranged from 5Ð2 to 8Ð1 mm, while the biases were between 12 and 10Ð5%.…”