The Fluxatron—A Revised Approach to the Measurement of Eddy Fluxes in the Lower Atmosphere

Abstract

As a result of experience gained with the Evapotron in the measurement of eddy fluxes, a new instrument called the Fluxatron has been developed. The computing efficiency has been improved by filtering out slow eddies which do not contribute to the eddy flux. The Fluxatron employs a propeller anemometer to detect the vertical wind component, and the response time of this device (0.3 sec) is suitable for measurements to be made at a height of 4 m. Only 2 W of battery power are consumed, in contrast to the Evapotron which uses 50N–100 W. The new instrument is extremely simple to operate in the field, and is thus suitable for use by relatively unskilled personnel. In its present form, the Fluxatron measures only sensible heat transfer. The measurement of the evaporative flux presents no difficulty in principle, but it is hoped that an alternative humidity sensor may be found other than a fine-wire wet bulb as in the Evapotron.