Physical robustness of canopy temperature models for crop heat stress simulation across environments and production conditions

Authors: WEBER, HEIDI - University Of Bonn; White, Jeffrey; Kimball, Bruce; EWERT, FRANK - Leibniz Centre; ASSENG, SENTHOLD - University Of Florida; REXAEI, ESHAN - University Of Bonn; PINTER, PAUL - Retired Non ARS Employee; Hatfield, Jerry; BINDI, MARCO - University Of Florence; DOLTRA, JORDI - Center For Agricultural Research And Training, Cantabria Government (CIFA); FERRISE, ROBERTO - University Of Florence; KASSIE, BALAY - University Of Florida; KAGE, HENNING - University Of Kiel; KERSEBAUM, KURT-CHRISTIAN - Leibniz Centre; LUIG, ADAM - University Of Kiel; OLESEON, JORGEN - Aarhus University; SEMENOV, MIKHAIL - Rothamsted Research; STRATONOVITCH, PIERRE - Rothamsted Research; RATJEN, ARNE - University Of Kiel; LAMORTE, ROBERT - US Department Of Agriculture (USDA); LEAVITT, STEEN - University Of Arizona; Hunsaker, Douglas - Doug; Wall, Gerard - Gary; MARTRE, PIERRE - Institut National De La Recherche Agronomique (INRA)

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2017
Publication Date: 2/15/2018
Publication URL: http://handle.nal.usda.gov/10113/5858773
Citation: Weber, H., White, J.W., Kimball, B.A., Ewert, F., Asseng, S., Rexaei, E.E., Pinter, P.J., Hatfield, J.L., Bindi, M., Doltra, J., Ferrise, R., Kassie, B., Kage, H., Kersebaum, K., Luig, A., Oleseon, J.E., Semenov, M.A., Stratonovitch, P., Ratjen, A., Lamorte, R.L., Leavitt, S.W., Hunsaker, D.J., Wall, G.W., Martre, P. 2018. Physical robustness of canopy temperature models for crop heat stress simulation across environments and production conditions. Field Crops Research. 216:75-88. https://doi.org/10.1016/j.fcr.2017.11.005.
DOI: https://doi.org/10.1016/j.fcr.2017.11.005

Interpretive Summary: The risk of crops failing due to heat stress may increase if future temperatures exceed thresholds for critical events in crop development such as during pollination, fertilization or seed formation. Despite widespread application in studies of climate uncertainty impacts on crops, most computer models of crop growth use air temperature to estimate impacts of heat stress, ignoring the complex ways that air temperature, crop water status, CO2 concentration and atmospheric conditions interact to influence the crop canopy temperature (Tc). The current study evaluated nine crop models, each implementing one of three approaches for estimating Tc. Model skill was evaluated for two experiments with wheat. The China Wheat experiment was conducted over two years at five North American locations and included rainfed and irrigated treatments. The FACE-Maricopa experiment was conducted over four years with ambient and elevated CO2, and two years each of nitrogen and water stress treatments. Across experiments and conditions, the models using the most complex approach (energy balance with consideration of atmospheric stability) for estimating Tc showed the best performance in simulating differences between Tc and air temperature (delta-T). For the FACE-Maricopa data, the portion of variation in observed delta-T explained by modeled values of delta-T was 34% with the most complex approach vs. 19% and 20% with the simpler approaches. For the China Wheat experiment, the portion of variation in observed delta-T was 34% for the complex approach vs. 20 and 7% for the others. There was no consistent relation between Tc model approach and the ability to simulate response to CO2 concentration. This model comparison shows that the more complex approach is required for accurate estimation of canopy temperature and hence is preferred for research on potential impacts of heat stress. These findings should ultimately contribute to improved management and breeding options for regions affected by heat stress.

Technical Abstract: Despite widespread application in studying climate change impacts, most crop models ignore complex interactions among air temperature, crop and soil water status, CO2 concentration and atmospheric conditions that influence crop canopy temperature. The current study extended previous studies by evaluating Tc simulations from nine crop models at six locations across environmental and production conditions. Each crop model implemented one of an empirical (EMP), an energy balance assuming neutral stability (EBN) or an energy balance correcting for atmospheric stability conditions (EBSC) approach to simulate Tc. Model performance in predicting Tc was evaluated for two experiments in continental North America with various water, nitrogen and CO2 treatments. An empirical model fit to one dataset had the best performance, followed by the EBSC models. Stability conditions explained much of the differences between modeling approaches. More accurate simulation of heat stress will likely require use of energy balance approaches that consider atmospheric stability conditions.