Showing papers by "Ulrich Platt published in 1988"

New tropospheric OH measurements

Abstract: New field measurements of atmospheric OH radicals by laser long-path absorption spectroscopy are reported: In the Black Forest, diurnal profiles of OH radical concentrations ranging up to 8.7×106 cm−3 have been observed during June 1984. Simultaneous measurements of other trace gases, photolysis frequencies, and meteorologic parameters were also made to allow comparison of observed OH levels with model calculations.

Measurement of tropospheric OH concentrations by laser long-path absorption spectroscopy

Abstract: Tropospheric hydroxyl (OH) radical concentrations were measured in summer 1987 in Jiilich by broadband laser long-path absorption (laser-LPA) spectroscopy observing the Q 1 (2), Q 2 1 (2).Q 1 (3).Q 2 1 (3). and P 1 (1) rotational absorption lines around 308 nm. The measurement technique was improved using a multichannel spectrometric detector to record the OH absorption spectra. Now a much wider spectral interval can be observed at high resolution; thus, registration and correction of overlapping absorption features of interfering trace gases is improved. Simultaneous to the OH measurements, the concentrations of nitrogen dioxide (NO 2 ), formaldehyde (HCHO), and sulfur dioxide (SO 2 ) were monitored by a second LPA spectrometer. Ozone (O 3 aerosol concentrations, meteorological parameters, and absolutely calibrated photolysis frequencies of O 3 and NO 2 were also recorded. Carbon monoxide (CO), methane (CH 4 ), and light hydrocarbons were determined by gas chromatographic analysis. OH concentrations ranged up to 6.8.10 6 molecules/cm 3 . At one day in July, an 'asymmetric' diurnal profile of the OH concentration was observed, which could be qualitatively explained by a strong decrease in the NO 2 concentration during the morning hours. DOI: 10.1111/j.1600-0889.1988.tb00115.x