L-A feedbacks depend on the exchange of water between the land and the atmosphere and more generally on L-A water pathways. A sound understanding of the processes related to L-A water pathways requires a joint measuring-modeling effort and the consideration of a great variety of both terrestrial and atmospheric variables, as they are offered by the LAFO observatory and LAFI. We will particularly consider stable water isotopologues and focus on the role of terrestrial hydrological processes on L-A feedbacks. The research objective of P9 is to improve our understanding of the relationship and interactions between groundwater, soil moisture in the unsaturated zone, ET partitioning, isotope signatures and L-A feedbacks. The research hypotheses of P9 are that the consideration of isotopes in a L-A system model allows to better constrain the partitioning between E and T, reduce systematic errors in simulated ET, and more accurately characterize L-A coupling strength. Our studies will be performed with the isotope-enabled version of the fully coupled atmospheric hydrological modeling system WRF-NoahMP-Gecros-Hydro-iso at turbulence permitting scales, which will allow to represent the isotopic fractionation processes associated with E and T at a relevant scale for comparison to in-situ isotope observation.
