| Autor: |
Trautz, Andrew C., Illangasekare, Tissa H., Howington, Stacy |
| Předmět: |
|
| Zdroj: |
Water Resources Research; Nov2018, Vol. 54 Issue 11, p8963-8982, 20p |
| Abstrakt: |
At the fundamental process level, many of the concepts that form the foundation of our understanding of bare‐soil evaporation dynamics have advanced little since their initial formation. This investigation explores experimental scaling issues that should be considered during the study of bare‐soil evaporation dynamics under conditions of sustained above‐ground airflow. Results are presented from a series of large‐scale laboratory experiments conducted for various soil conditions (i.e., heterogeneity and surface roughness). Fundamental experimental research of this nature is not feasible in the field or small laboratory columns that are limited by system control and scale. All experimentation was therefore conducted in a test facility that couples a climate‐controlled, low‐speed wind tunnel with a 7.15‐m‐long soil tank—allowing for control over soil properties and initial and boundary conditions. Measured flow phenomena supported, and agreed well with, existing wind tunnel and field study literature. These data were in turn, used to explain observed evaporative water loss and soil moisture distribution spatiotemporal trends and patterns. Results demonstrated that relatively large length scales are required for the impacts of atmospheric feedbacks on the subsurface hydrodynamics to manifest themselves and become quantifiable. Airflow had the greatest impact in the case of a flat homogeneous soil; the strength of this feedback was significantly weaker in the presence of soil heterogeneities and surface undulations that were dominated by other transport phenomena. Comparison of these results with those of past studies furthermore cautions against the use of column scale data to make generalizations about bare‐soil evaporation dynamic upscaling. Key Points: Sufficiently large length scales are needed to study aboveground airflow‐driven evaporation dynamicsTheory developed from small laboratory column data sets may not upscale directly, showing the importance of large scale experimentation [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text