Fang, B;Zhao, WX;Xu, XZ;Zhou, JC;Ma, X;Wang, S;Zhang, WJ;Venables, DS;Chen, WD

2017

October

Optics Express

Portable broadband cavity-enhanced spectrometer utilizing Kalman filtering: application to real-time, in situ monitoring of glyoxal and nitrogen dioxide

Validated

WOS: 29 ()

LASER-ABSORPTION-SPECTROSCOPY SCATTERING CROSS-SECTION CE-DOAS INSTRUMENT 2.73 MU-M AEROSOL EXTINCTION AIRCRAFT MEASUREMENTS METHYL GLYOXAL WATER-VAPOR NO2 METHYLGLYOXAL

25

26910

26922

This article describes the development and field application of a portable broadband cavity enhanced spectrometer (BBCES) operating in the spectral range of 440-480 mu for sensitive, real-time, in situ measurement of ambient glyoxal (CHOCHO) and nitrogen dioxide (NO2). The instrument utilized a custom cage system in which the same SMA collimators were used in the transmitter and receiver units for coupling the LED light into the cavity and collecting the light transmitted through the cavity. This configuration realised a compact and stable optical system that could be easily aligned. The dimensions and mass of the optical layer were 676 x 74 x 86 mm(3) and 4.5 kg, respectively. The cavity base length was about 42 cm. The minor reflectivity at lambda = 460 nm was determined to be 0.9998, giving an effective absorption pathlength of 2.26 km. The demonstrated measurement precisions (1 sigma) over 60 s were 28 and 50 pptv for CHOCHO and NO2 and the respective accuracies were 5% and 4%. By applying a Kalman adaptive filter to the retrieved concentrations, the measurement precisions of CHOCHO and NO2 were improved to 8 pptv and 40 pptv in 21 s. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

WASHINGTON

1094-4087

10.1364/0E.25.026910