Abstract: A thorough understanding of the impact of heat wave on crop yield is the basis for agriculture adaptation to future climate change. Despite abundant evidence of heat wave-caused crop yield loss, there have been few studies investigating the role of evapotranspiration (ET) during heat waves as a control on the damaging effect of heat. Furthermore, because crop growth has a strong influence on ET in breadbasket regions, it is possible that the ET produced by crops modulates the effect of heat on those same crops. Given so, this study tentatively investigates the interaction between yield, heat waves, and ET during heat waves. The metric killing degree days (KDDs) is commonly used as a proxy for crop-damaging heat. We use daily temperature data from ERA5 and 8-day ET product (MOD16A2) to show that only 40.9% of KDDs – those that co-occur with below average ET – are damaging to corn yield. When ET is above the local average, KDDs have no negative effect on corn yield. Additionally, we show that local ET is strongly dependent on local soil moisture conditions. Our work provides a more detailed understanding of the climate conditions that damage crop yields and provides insight into the mechanisms by which crop growth can modify regional climate.
