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United States Department of Agriculture (USDA) 2009

A NOVEL APPROACH TO QUANTIFYING SOIL EVAPORATION RATES WITH HIGH RESOLUTION THERMAL IMAGING AND HEAT FLUX MEASUREMENTS

Soil Evaporation

United States Department of Agriculture (USDA) Research, Education & Economics Information System (REEIS)

Titre : A NOVEL APPROACH TO QUANTIFYING SOIL EVAPORATION RATES WITH HIGH RESOLUTION THERMAL IMAGING AND HEAT FLUX MEASUREMENTS

Identification : ARZT-3200300-G21-519

Pays : Etats Unis

Durée : Sep 1, 2009 Aug 31, 2014

Domaine : soil evaporation ; predictive models ; high resolution thermal imaging ; penta needle heat pulse technology ; thermal footprints ; weighing lysimetry ; thermal soil properties ; soil texture

Partenaire : UNIVERSITY OF ARIZONA 888 N EUCLID AVE TUCSON,AZ 85719-4824

Objectifs
Soil evaporation is an extremely important component of the water balance in semiarid and arid regions. Latest technological advances that allow measurement of temperature surface footprints and evaporative fluxes at unprecedented resolution, recent development of novel physically-based pore and sample-scale approaches for prediction of evaporation rates and our long-term goal to understand and accurately describe and measure status and behavior of water in the vadose zone and at the soil-plant-atmospheric interface provide the motivation and rationale for this project. Within this context, the specific objectives of the proposed project are : (1) To apply High-Resolution Thermal Imaging (HRTI) and Penta-Needle Heat Pulse Probe (PHPP) technology in conjunction with well-controlled weighing lysimetry and field experiments to investigate correlations between thermal surface footprints, physical and hydraulic soil properties, atmospheric conditions, and transient evaporative fluxes from homogeneous soils and soils with textural contrasts. (2) To capitalize on insights gained under objective 1 and expand recently developed pore and sample-scale approaches for prediction of evaporation rates from thermal footprints and physical properties to the pedon- and field-scales. (3) To experimentally verify mechanisms for evaporation suppression and develop management strategies directly applicable to agriculture and urban landscaping. The project will provide new insights for the development of advanced management strategies for reducing evaporation rates in urban, agricultural, and natural settings to conserve precious water resources in arid environments. Based on gained data and follow-on projects, we will develop advanced surface covers for urban landscaping and novel surface preparation strategies for agricultural and environmental management for significant reduction of soil evaporation rates. For the long run, we envision scaling the developed models to field and landscape scales to predict large-scale evapotranspiration based on thermal satellite images.

Descriptif
A recently released and acquired High-Resolution Thermal Imaging (HRTI) system and arrays of newly developed Penta-Needle Heat Pulse Probes (PHPPs) will be employed to measure the spatial distribution of surface temperature and evaporative fluxes during well-controlled evaporation experiments in large weighing lysimeters and a nearby field plot. We hypothesize that HRTI surface temperature measurements can be correlated to evaporation rates (based on atmospheric conditions and soil properties) and used to predict Stage 1 and Stage 2 evaporative fluxes as well as the transition between stages for uniform and texturally contrasting soils. The COMSOL Multi-Physics modeling platform will be applied to numerically solve the heat flow equation and predict evaporation rates from thermal footprints (HRTI), soil thermal properties (PHPP) and measured boundary conditions. These calculations will be verified based on mass loss measured with the highly sensitive lysimeter scales. Drying front depths in coarse and fine textured regions will be continuously monitored with Sentek EnviroSCAN profiling moisture probes that will be carefully calibrated for soil texture and potential temperature effects. As a second novel means for estimating evaporation rates, we will deploy arrays of PHPPs. The PHPP arrays perform both active and passive heat flux measurements. The active heat pulse measurement estimates soil thermal properties and water flux. The passive soil heat flux and heat storage measurements are utilized for estimating soil evaporation

Présentation : USDA

Page publiée le 29 octobre 2015, mise à jour le 7 novembre 2017