IsoFlux: Isotope-enabled flux partitioning of evapotranspiration in five Swiss forest and grassland ecosystems
Context
The exchange of water and energy between the land surface and the atmosphere is a fundamental driver of climate and strongly depends on ecosystem functioning. In terrestrial ecosystems, evapotranspiration (ET) links soil moisture, vegetation ecophysiology, and atmospheric processes, thereby also affecting ecosystem carbon fluxes. Although, the partitioning of ET into evaporation (E) and transpiration (T) is at the core of our understanding of ecosystem water fluxes and ecosystem resilience against climate extremes, current methods are scarce, often also limited by assumptions about the water sources sustaining E and T.
Project aims
IsoFlux aims to advance the mechanistic understanding of ET dynamics in five forest and grassland ecosystems in Switzerland by integrating high-frequency in-situ water vapor isotope measurements and ET flux data. The specific project goals are: 1) to establish, test and deploy a continuous in-situ water isotope observation system at five existing eddy-covariance (EC) sites along an elevational gradient (Swiss FluxNet), 2) to attribute water sources for evaporation and transpiration at five forest and grassland sites (WP2), and 3) to partition ET measured with the EC technique and determine drivers of ET, E, and T using isotope-based as well as flux-based partitioning methods.