Impact of land use change on the diurnal cycle climate of the Canadian Prairies

摘要: [1] This paper uses hourly observations from 1953 to 2011 of temperature, relative humidity, and opaque cloud cover 14 climate stations across the Canadian Prairies analyze impact agricultural land use change on diurnal cycle climate, represented by mean temperature humidity their ranges. We show difference between years 1953–1991 1992–2011. The changes have been largest in Saskatchewan where 15–20% area has converted past four decades summer fallow (where was left bare for 1 year) annual cropping. During growing season 20 May 28 August, increased about 7%. first 2 months, 19 July, maximum temperatures range fallen 1.2°C 0.6°C, respectively, 4%, reducing surface net radiation 6 W m−2, precipitation increased. dry-downs after separate coupling evapotranspiration humidity. estimate, using reanalysis data ERA-Interim, that transpiration larger cropland reduced Bowen ratio 0.14–0.2. For month either side season, slightly; increased, increasing