GRAPEX Below-Canopy Turbulence & Radiation

Sub-Canopy Fast Response H₂O & CO₂  measurements and 3D Sonic Anemometry

During intensive observation periods (IOPs) fast response instrumentation was placed at both Borden sites of the GRAPEX project within the row space between vine canopies. This instrumentation consisted of a LI-COR LI-7500 IRGA and an ATI Sonic Anemometer per site. These were placed at a ~1.45 m height from the surface on a tripod in the row space centered between vine trellises. The instrumentation was placed in the row immediately to the North of the fixed flux tower at each site directly North or slightly Northwest of the tower. For the 2016 field season the ATI anemometers and LI-7500 were both placed on the same datalogger as the suite of flux tower fast response sensors allowing synchronization between all sensors.

Radiation Divergence Measurements

Radiation divergence measurements were collected during the IOPs.  In 2013 there was one radiation system comprised of 3 Epply PSP (Precision Spectral Pyranometers) and 5 Apogee pyranometers (model CS300) and positioned in both site 1 (north vineyard) and site 2 (south vineyard) within the flux tower footprint and LAI sampling area.  In 2014 an additional radiation board was constructed made up of Kipp and Zonen pyranometers (model CMP11 and CMP21).  

Example plot of incoming solar radiation (solid black line), average of radiation reaching the inter-row (solid red line) and individual pyranometer measurements using the Kipp & Zonen pyranometer array at site 1 (north vineyard) and the Apogee/Eppley pyranometers at site 2 (South vineyard)