Energy exchanges between a pasture and the atmosphere under steady and non-steady-state conditions

✍ Scribed by C.W. Rose; J.E. Begg; G.F. Byrne; J.H. Goncz; B.W.R. Torssell

• Publisher: Elsevier Science
• Year: 1971
• Weight: 1015 KB
• Volume: 9
• Category: Article
• ISSN: 0002-1571
• DOI: 10.1016/0002-1571(71)90035-5

✦ Synopsis

Micrometeorological theory describing energy and mass exchange between vegetation and the atmosphere currently assumes these fluxes to be steady-state and one-dimensional in character. The main aim of this paper is to test the validity of applying such theory to a variety of non-steady-state environmental situations, by determining the errors involved. Energy exchanges were determined for a growing pasture of Townsville stylo (Stylosanthes humilis H.B.K.) at Katherine, N.T., Australia. Both latent and sensible heat fluxes were measured at two sites, and independently obtained by weighing lysimeter and fluxatron respectively. Advection theory indicates that the modest variation in fluxes between sites must be due to inhomogeneities within the experimental area. Critical comparison between latent heat fluxes measured by lysimeter and adjacent micrometeorological profile showed agreement to within 6Yo under steady conditions. Under highly variable radiation, however, micrometeorological techniques underestimated latent heat flux by up to 18~ when compared with measurement by weighing lysimeter over a period of nearly a day. The origin of such discrepancies requires further clarification.