26th Conference on Agricultural and Forest Meteorology


Flux profiles in and above an olive and a cork oak canopy

Roland Vogt, University of Basel, Basel, Switzerland; and A. Christen and A. Pitacco

As part of the European project WATERUSE two field studies were carried out in two Mediterranean tree canopies (olives and cork oaks). The main goal was the investigation of the water use of the two canopies and the improvement of parameterisation of the transfer process based plant physiological properties. As a subproject we carried out micrometeorological experiments, in order to compare vertical profiles of turbulent exchange properties of the two contrasting rough canopies. The first, an olive tree plantation, is located 5 km E of Canosa di Puglia, IT (4112N, 1610E, 175 m a.s.l.) on appox. level terrain (2 inclined towards NNE). The stand age was 100 years. The distance between the rows was 8.3 m and the tree density was 132 trees per ha, with an average tree height of 5 m. Between the trees was bare soil and the canopy was relatively open. Fetch in the main wind directions (W and N) was 200 to 300 m. The experiment took place from July 27 to August 6, 2002. The tower in the olive canopy supported 7 levels with sonic measurements (6 Campbell CSAT3 and 1 Gill HS), which were mounted at z/h = 0.13, 0.33, 0.72, 0.91, 1.19, 1.6, and 2.43. At the top level an open path gas analyser (Li7500) measured the H2O and the CO2 concentration fluctuations. The second canopy, a cork oak plantation, is located 35 km SE of Lisbon, PT (3838N, 851W; 30 m a.s.l.) on level terrain. The age of the trees was 100 years and they were planted in rows with 10 m distance. The tree density was 76 trees per ha in 2001 with some reduction in early 2003 and the average canopy height was 10m. The understorey was patchy and varied between dry grass and shrubs (cistus), the latter reached in average up to 0.4 m. Fetch conditions in the main wind direction (NW) were good, with some variation in tree density further upwind. Measurements were carried out from July 1 to July 13, 2003. The tower in the cork oak canopy supported 9 levels with sonic measurements (8 Campbell CSAT3 and 1 Gill HS), which were mounted at z/h = 0.09, 0.18, 0.43, 0.77, 0.96, 1.17, 1.4, 1.68 and 2.07. At five levels (z/h = 0.18, 0.77, 1.17, 1.4 and 2.07) open path gas analysers (Li7500) additionally measured the H2O and the CO2 concentration fluctuations. Vertical profiles of sensible, latent heat and CO2 fluxes are presented. Turbulent properties of the flow are displayed the manner of family portraits.

Session 3, Canopy micrometeorology 2
Tuesday, 24 August 2004, 8:30 AM-2:30 PM

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