Limitations of an eddy-correlation technique for the determination of the carbon dioxide and sensible heat fluxes

✍ Scribed by R. L. Desjardins; E. R. Lemon

• Publisher: Springer
• Year: 1974
• Tongue: English
• Weight: 984 KB
• Volume: 5
• Category: Article
• ISSN: 0006-8314
• DOI: 10.1007/bf00123493

✦ Synopsis

A modified infrared COz gas analyzer, a small thermocouple assembly, a heated-thermocouple anemometer for horizontal wind, and a propeller-type vertical wind sensor were used to measure the eddy fluxes of heat and COZ above a corn crop. Experimental results of these fluxes are discussed. The main sources of errors of the eddy fluxes using these instruments were estimated :

(1) Sensors with a time constant of 0.5 s appear to be fast enough to detect most of the vertical COa transfer as long as the sensors are located at least one meter above the crop surface.

(2) The deviation from steady-state conditions for IO-min periods was found to have a significant effect on the eddy flux estimates.

(3) Temperature fluctuations of the air sample passing through the COZ infrared gas analyzer were found to be non-negligible but could be easily corrected.

(4) A 1" misalignment of the vertical anemometer affected these eddy fluxes by less than 10 % under all circumstances studied.