Field Tests of Measuring System of Vegetation Response to Environmennt in a Barley Field

A system designed to measure the vegetation response to environment was constructed on the basis of the eddy correlation method.It consisted of two sets of a small rapid response sensors; three dimensional sonic anemometer thermometers and infrared CO2-humidity fluctuation meters,and a personal computer for data acquisition. Field tests of the system were made over a barley field in April and May,1990.The turbulent fluxes obtained by two sets of flux measuring system mounted at the same height were in fair agreement. The turbulent fluxes(momentum,sensible heat,latent heat and carbon dioxide) measured at two height wihtin and above plant cannopies and their differences showed realistic diurnal variations.The direction and magnitude of each flux varied depending on the srength or distribution of source and sink within plant canopies. These findings confirmed that this measureing system is promising for quantitative estimate of vegetation response such as transpiration, photosynthesis and respiration in certain canopy layers to environmental variations.