Ultrasonic Detector for High Precision Measurements of Carbon Dioxide

摘要

A new instrument for monitoring atmospheric CO_(2) has been developed based on the measurement of the speed of sound in air. The instrument uses a selective scrubber to yield highly precise and accurate measurements of CO_(2) mixing ratios at ambient concentrations. The instrument has a precision of 0.3 ppmv (1sigma) with a signal that is independent of pressure and requires a flow rate of only 30 mL/min. Laboratory measurements of atmospheric CO_(2) showed excellent agreement with values obtained by nondispersive infrared absorption. The instrument has the advantage of collecting continuous, high-precision data every 25 s and can be modified for vertical profiling studies using kites, balloons, or light aircraft for the purpose of measuring landscape-scale fluxes.