Turbulence‐induced thermal signatures over evaporating bare soil surfaces

Abstract

AbstractSoil wetness and airflow turbulence are key factors affecting surface energy balance components thereby influencing surface skin temperature. Turbulent eddies interacting with evaporating surfaces often induce localized and intermittent evaporative and sensible heat fluxes that leave distinct thermal signatures. These surface thermal fluctuations observable by infrared thermography (IRT) offer a means for characterization of overlaying turbulent airflows and remote quantification of surface wetness. We developed a theoretical and experimental methodology for using rapid IR surface temperature measurements to deduce surface wetness and evaporative fluxes from smooth bare soils. The mechanistic model provides theoretical links between surface thermal fluctuations, soil, and aerodynamic properties enabling thermal inferences of soil wetness with explicit consideration of soil thermal capacity and airflow turbulence effects. The method potentially improves accuracy of soil wetness assessment by IRT‐based techniques whose performance is strongly influenced by surface‐turbulence interactions and offers new ways for quantifying fluxes directly at their origin.