Flux-angle distribution of momentum and sensible heat over a vegetated surface

✍ Scribed by Raymond P. Motha; Shashi B. Verma; Norman J. Rosenberg

• Publisher: Elsevier Science
• Year: 1980
• Weight: 419 KB
• Volume: 22
• Category: Article
• ISSN: 0002-1571
• DOI: 10.1016/0002-1571(80)90038-2

✦ Synopsis

Turbulence was measured over an irrigated alfalfa crop under conditions of sensible heat advection and under non-advective conditions. Flux-angle distributions for momentum and sensible heat were developed from these measurements. The range of updraft angles decreased under advective as compared to ]apse conditions indicating a decrease in significance of thermal turbulence under advection. Downdraft angles associated with the transfer of momentum and sensible heat did not change significantly under advective conditions. The normalized flux-angle distributions not only provide information on the range of angles for which there is transfer of an entity but also indicate the proportion of flux transferred at each angle. Updrafts were found to be less efficient in transporting momentum under advective than under lapse conditions due, probably, to a decreased contribution from thermal turbulence. For sensible heat transfer, however, there was a significant contribution by updrafts to the net flux toward a vigorously transpiring crop under advective conditions.