A Suite of Models for Producing Synthetic, ...

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XVI International Conference on Computational Methods in Water Resources (CMWR-XVI) Ingeniørhuset

A Suite of Models for Producing Synthetic, Small-scale Thermal Imagery of Vegetated Soil Surfaces
Author:Stacy Howington <stacy.e.howington@erdc.usace.army.mil> (Engineer Research and Development Center)
John Peters <john.f.peters@erdc.usace.army.mil> (Engineer Research and Development Center)
Jerry Ballard <jerry.ballard@erdc.usace.army.mil> (Engineer Research and Development Center)
Thomas Berry <thomas.e.berry@erdc.usace.army.mil> (Engineer Research and Development Center)
Larry Lynch <larry.n.lynch@erdc.usace.army.mil> (Engineer Research and Development Center)
Chris Kees <christopher.e.kees@erdc.usace.army.mil> (Engineer Research and Development Center)
Presenter:Stacy Howington <stacy.e.howington@erdc.usace.army.mil> (Engineer Research and Development Center)
Date: 2006-06-18     Track: Special Sessions     Session: Field measurements and simulations of land-atmosphere interaction

A high-resolution, computational suite has been constructed to produce synthetic thermal imagery of vegetated soil surfaces. Because a soil’s moisture affects its thermal response, the model suite must include both moisture and energy movement within the soil and plants. Thus, the suite consists of a soil model, a vegetation model, and a ray-casting model. The models run simultaneously on a single, parallel or serial computer and communicate using sockets. The soil model is a three-dimensional, spatially adaptive, continuous Galerkin, finite element model that simulates partially-saturated flow and heat transport, coupled to two-dimensional surface water flow. The vegetation model simulates infrared absorption, reflection, and transmission by discretized plant leaves and stems. Ray casting provides boundary conditions for the soil and vegetation thermal models, and produces multi-spectral images of energy reflected and emitted from the synthetic scene. Subsurface phase change, distributed root zone moisture uptake and transpiration, and flow through macropores and cracks are processes under construction. Example calculations to be presented include a multi-million-element simulation for an arid test site that is only a few meters in its longest dimension. The models are driven with meteorological data and are built using material property data collected at the field site. Synthetic images produced are compared against those from thermal cameras. A long-term goal of this work is to help build inversion software to estimate ground state information (soil moisture and physical property distributions) from airborne imagery.