Analysis System for Measurement of CO2Mixing Ratios in Flask Air Samples

Abstract

A system for measuring the concentration of CO₂ in flask air samples from the NOAA/CMDL worldwide flask sampling network is described. Up to 180 samples per day can he analyzed using a nondispersive infrared CO₂ analyzer. All data acquisition and instrument control operations are handled by a Hewlett-Packard Series 300 desktop computer. A noncontaminating diaphragm pump transfers the sample from the flask to the NDIR CO₂ analyzer. Tests conducted using flasks filled from tanks of dry air showed either no systematic offsets or a small offset of about 0.1 ppm. The precision of the analysis system is estimated to be better than 0.1 ppm.