Stomatal response to humidity and CO2 implicated in recent decline in US evaporation.

摘要: Evapotranspiration, defined as the total flux of water from land surface to atmosphere, is a major component hydrologic cycle and energy balance. Although evapotranspiration expected intensify with increasing temperatures, long-term, regional trends in remain uncertain due spatially temporally limited direct measurements. In this study, we utilize an emergent relation between atmospheric boundary layer infer daily historical meteorological data collected at 236 weather stations across United States. Our results suggest statistically significant (α = 0.05) decrease approximately 6% 1961 2014, sharp decline 13% 1998 2014. We attribute mostly declines conductance, but also offsetting changes longwave radiation, wind speed, incoming solar radiation. Using established stomatal conductance model, explain inferred response increases carbon dioxide and, more recently, abrupt humidity.