Patch scale turbulence over dryland and irrigated surfaces in a semi-arid landscape under advective conditions during BEAREX08

J. H. Prueger, J. G. Alfieri, L. E. Hipps, W. P. Kustas, J. L. Chavez, S. R. Evett, M. C. Anderson, A. N. French, C. M.U. Neale, L. G. McKee, J. L. Hatfield, T. A. Howell, N. Agam

Research output: Contribution to journalArticlepeer-review


Quantifying turbulent fluxes of heat and water vapor over heterogeneous surfaces presents unique challenges. For example, in many arid and semi-arid regions, parcels of irrigated cropland are juxtaposed with hot, dry surfaces. Contrasting surface conditions can result in the advection of warm dry air over an irrigated crop surface where it increases the water vapor deficit and, thereby, atmospheric demand. If sufficient water is available, this can significantly enhance evaporative water loss from the irrigated field. The scale and frequency of turbulent eddies over an irrigated surface during periods of strong advection is not fully understood. High frequency (20. Hz) data were acquired over irrigated cotton, wheat stubble, and rangeland fields during the 2008 growing season as part of the Bushland Evapotranspiration and Agricultural Remote Sensing Experiment (BEAREX08). Spectral analysis of momentum and scalar quantities including heat and water vapor revealed low frequency features in the turbulence structure due to the penetration of the surface boundary layer by large-scale eddies during periods of unusually strong advection. Wavelet analysis was applied to assess specific events contributing to the spatial and temporal structure of turbulent flux eddies. The analysis showed that low frequency contributions were linked to both local and regional scale advective processes. These results clearly point to a need to better understand surface energy balance exchange for heterogeneous surfaces in arid and semi-arid regions under conditions of strong local and regional advection.

Original languageAmerican English
Pages (from-to)106-119
Number of pages14
JournalAdvances in Water Resources
StatePublished - 1 Dec 2012
Externally publishedYes


  • Advection
  • Eddy covariance
  • Evapotranspiration
  • Surface energy flux
  • Surface heterogeneity
  • Turbulence

All Science Journal Classification (ASJC) codes

  • Water Science and Technology


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