title: Near-infrared open-path measurement of CO₂ concentration in the urban atmosphere.
abstract: Average concentration of carbon dioxide (CO2) has been measured over a path length of 5.1 km in the lower troposphere by the method of differential optical absorption spectroscopy (DOAS) using a near-infrared light source based on amplified spontaneous emission. The analysis of CO2 absorption intensity around 1575 nm observed during 10 days over the Chiba city area has revealed that the CO2 concentration varied in the range of around 360-450 ppmv, with presumable influence of air mass advection from nearby industrial facilities. In addition, a good correlation has been found in relative humidity values between the DOAS and meteorological station data. As a whole, the present result indicates the usefulness of such a DOAS approach for measuring the concentration of CO2 averaged over an optical path of a few kilometers in the lower troposphere.
authors.forename: Hayato
authors.initials: H
authors.lastname: Saito
authors.forename: Naohiro
authors.initials: N
authors.lastname: Manago
authors.forename: Kenji
authors.initials: K
authors.lastname: Kuriyama
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kuze