Submitted to: US-International Association for Landscape Ecology
Publication Type: Abstract Only
Publication Acceptance Date: 2/19/2020
Publication Date: 5/10/2020
Citation: Goslee, S.C. 2020. Growing degree day dynamics across the contiguous United States[Abstract]. US-International Association for Landscape Ecology. p. 1.
Interpretive Summary: No Interpretive Summary is required for this Abstract Only. JLB.
Technical Abstract: Describing weather and climate in organism-relevant ways is a key aspect of understanding the potential agricultural effects of changing climate, and requires integrating multiple disciplines. Growing degree days (GDD), a measure of heat accumulation, are a simple metric commonly used in agriculture, for instance to predict timing of crop growth stages or insect pest outbreaks. The cumulative GDD at which a crop flowers or reaches maturity can be used to plan management activities, and more broadly to assess the suitability of a region for a particular crop. Growing degree days were calculated from daily PRISM temperature data for 1981-2018 using bases of 5C (for C3 crops such as wheat) and 10C (for C4 crops such as corn), as well as base 0C and 30C. Monthly temperature data from 1895-2018 were interpolated to calculate GDD over a longer timespan. Since 1981, there have been slight declines in total GDD over the Great Plains, and strong increases in the southwestern US. The long-term data show significant decreases in total GDD across the southeastern US due to increased precipitation. Changes in GDD, and in the shape of the GDD accumulation curve, have implications for crop suitability and the timing of plant and insect phenological stages.