Connections between groundwater flow and transpiration partitioning

Abstract

Understanding freshwater fluxes at continental scales will help us better predict hydrologic response and manage our terrestrial water resources. The partitioning of evapotranspiration into bare soil evaporation and plant transpiration remains a key uncertainty in the terrestrial water balance. We used integrated hydrologic simulations that couple vegetation and land-energy processes with surface and subsurface hydrology to study transpiration partitioning at the continental scale. Both latent heat flux and partitioning are connected to water table depth, and including lateral groundwater flow in the model increases transpiration partitioning from 47 ± 13 to 62 ± 12%. This suggests that lateral groundwater flow, which is generally simplified or excluded in Earth system models, may provide a missing link for reconciling observations and global models of terrestrial water fluxes.

The evolution of process-based hydrologic models: historical challenges and the collective quest for physical realism

“…The first solution, and the most obvious, is to exploit advances in massively parallel (e.g., exa-scale) computation (Kollet et al, 2010;Wood et al, 2011;Paniconi and Putti, 2015;Fatichi et al, 2016). This solution is often implemented by running a complex model at the finest grid resolution possible over the domain of interest (e.g., Maxwell et al, 2015;Maxwell and Condon, 2016). A key reason for conducting such spatially resolved simulations is to understand explicit spatial controls on hydrologic processes.…”

“…A key reason for conducting such spatially resolved simulations is to understand explicit spatial controls on hydrologic processes. For example, Maxwell and Condon (2016) use high-resolution continental-domain ParFlow simulations to understand the controls of groundwater flow on the partitioning of evapotranspiration into bare soil evaporation and transpiration.…”

Tuning Transpiration by Interfacial Solar Absorber‐Leaf Engineering

“…Plant transpiration, a process of water movement through a plant and its evaporation from aerial parts especially leaves,3 consumes a large component of the total continental precipitation (≈48%)1, 2 and significantly influences global water distribution and climate 4. To date, various chemical and/or biological explorations have been made to suppress the transpiration but with uncertain environmental risks 5, 6, 7, 8, 9.…”

Scaling, similarity, and the fourth paradigm for hydrology

“…Similarly, one might imagine different scaling relations for evapotranspiration depending on the nature of controls due to radiation (topography), vegetation, and/or soil moisture (e.g., Rigden and Salvucci, 2015). For example, as recently shown by Maxwell and Condon (2016), the interplay of water table depths with rooting depths along a given hillslope exerts different controls on evaporation and transpiration, which links the water table dynamics with the land surface energy balance, even on continental scales. This finding is based on limited data, and would benefit from formal hypothesis testing in an information-based framework, as described in the next section.…”