Advith's Calendar

Virtual Laboratory for Understanding the Role of Scale and Topographic Heterogeneity in Ecohydrologic Modeling

Advisor: Professor Praveen Kumar

Abstract

Representing spatial heterogeneity remains a fundamental challenge in land surface modeling due to the nonlinear nature of ecohydrologic processes and their interactions. Processes such as infiltration, evapotranspiration, subsurface flow, and plant water uptake occur at fine spatial scales that often cannot be fully resolved in models, leading to errors when variability is aggregated. While advances in computation and data availability have led to a push physically based hyper-resolution models hyper-resolution modeling (~100 m to 1 km), the role of micro-topographic variability at scales finer than ~100 m has yet to be systematically explored.

This thesis aims to quantify the effects of model resolution and topographic heterogeneity on simulated ecohydrologic processes. To achieve this, a high-resolution, physically based modeling framework, the Multi-Layer Canopy and 3D Soil model (MLCan3D), is developed. It couples detailed vegetation process representation with three-dimensional surface-subsurface flow model and is validated against observations and existing models. To assess the impact of model scale, simulations are conducted across multiple spatial resolutions for three sites from the National Ecological Observatory Network. Results indicate that effects of model resolution and aggregation of micro-topography occur mainly at the local scale where soil moisture differences can be strongly event and location dependent but do not propagate significantly to the plot level. This work advances the understanding of the effects of model scale and topographic heterogeneity on ecohydrologic processes and contributes a novel modeling framework to explore such problems through the development of MLCan3D.