RECYCLING AND HYDRAULIC REDISTRIBUTION: MECHANISMS OF INTERACTION BETWEEN THE MOISTURE RESERVOIRS OF THE DEEP SOIL, VEGETATION, AND THE ATMOSPHERE

This talk will discuss new dynamic models that explain how precipitation recycling, and hydraulic redistribution in the sub-surface by vegetation impacts the interaction between the land and atmosphere. Hydraulic redistribution refers to moisture that moves via the root system from moist soil layers to dry soil layers. We model the hydraulic redistribution by assuming that the plant root system as a conduit for moisture transport from wet soil reservoirs to dry soil reservoirs, while at the same time conveying moisture to fulfill the transpiration demand at the canopy. While the hydraulic redistribution is a mechanism for reuse of sub-surface moisture, recycling, is a mechanism for reuse of atmospheric moisture of local origin. We model recycling using an analytical method that enables us to study the process at a short time scale of hours to days. The models for these two processes shed deep insight into the active role of vegetation in the dynamics at the land-atmosphere interface.