A correction for the effect of drying of air samples and its significance to the interpretation of atmospheric CO2 measurements

摘要: Non-dispersive infrared gas analysers used for the measurement of atmospheric carbon dioxide concentration are influenced by water vapour in air sample. It has thus become common practice to dry prior analysis. The subsequent must be corrected multiplying indicated (1 + 1.61 r ) ?1 , where is mass mixing ratio undried air. correction order 1% near surface, varying both space (e.g. with latitude) and time day-today seasonally), same magnitude as measured but uncorrected horizontal, vertical seasonal CO 2 variations. Thus serious doubt thrown on previous comparisons global measurements. Ideally each analysis an sample should using knowledge For data obtained past, appropriate may possible after consideration conditions atmosphere at monitoring stations. This done research personnel involved programme, together a effects carrier composition analyser(s) employed. DOI: 10.1111/j.2153-3490.1975.tb01680.x