Turbulence venting in riparian vegetation and connections to transpiration

We investigate factors governing transpiration of Tamarisk riparian vegetation along the Rio Grande in New Mexico. Tamarisk combines properties of high density, high stomatal conductance, and heights of a small forest. In addition to available energy, data suggest transpiration often responds to import of saturation deficit from the mixed-layer. This suggests transpiration in the humid canopy can be limited by exchange of saturation deficit with the atmosphere. By quantifying the turbulent exchange and venting of the canopy, we presume to detail mechanisms by which the vegetation couples to the atmosphere to affect transpiration. A 12 m tower was sited in Tamarisk 4 m in height, with an eddy covariance system above the canopy and near the ground. 3-D winds, temperature, and humidity were sampled at 20 Hz. Various turbulent statistics and coherence between above and below the canopy will be examined and connected to the enhancement of transpiration.