The importance of plant-water stress for predictions of ground-level ozone in a warm world

Tamara Emmerichs, Yen-Sen Lu, and Domenico Taraborrelli

Abstract

Evapotranspiration is important for Earth’s water and energy cycles as it strongly affects air temperature, cloud cover and precipitation. Leaf stomata are the conduit of transpiration and thus their opening is sensitive to weather and climate conditions. This feedback can exacerbate heat waves and droughts and can play a role in their spatio-temporal propagation. Therefore, the plant response to available water is a key element mediating vegetation-atmosphere interactions. Sustained high temperatures strongly favor high ozone levels with significant negative effects on air quality and thus human health. Our study assesses the process representation of evapotranspiration in the atmospheric chemistry model ECHAM/MESSy. Diverse water stress parametrizations are implemented in a stomatal model based on CO₂ assimilation. ...