Radiation Sensors
2021-08-05 12:37:01.0 [sritz] insert AltLabel (id: null category: primary text: LICOR PLANT CANOPY ANALYZER language code: en);
The Li-Cor Plant Canopy Analyzer sensing head has five concentric silicon ring detectors beneath a nearly hemispherical (150? field of view) lens. A blocking filter restricts radiation of less than 490 nm, which minimizes the effect of light scattered by foliage (Welles, 1990 ). The five rings provide data at five zenith angles for use in the inversion model. A separate dedicated controller-data logger is attached to the sensing head and records light readings for each ring. Readings of above- and below-canopy light conditions are necessary for the calculation of LAI and average leaf inclination angle by the built-in program. Below-canopy data were taken at eight compass directions and the mean of these values was stored in the instrument. In the orchard, above-canopy data were taken by walking to an adjacent open field immediately (less than 2 min) after recording each below-canopy reading. In the forest, above-canopy readings were acquired by another Plant Canopy Analyzer unit atop a nearby butte, which was about 1 km south and at 50 m higher elevation. Data were recorded every 5 min during the period in which below-canopy readings were made. Above-canopy values were then linearly interpolated to provide an appropriate value for each below-canopy reading. Additional information available at "http://www.cstars.ucdavis.edu/papers/pdf/martensetal1993a.pdf"
LICOR PLANT CANOPY ANALYZER