Rotational vibrational-rotational Raman differential absorption lidar for atmospheric ozone measurements: methodology and experiment

A single-laser Raman differential absorption lidar (DIAL) for ozone measure ments in clouds is proposed. An injection-locked XeCl excimer laser serves as the radiation source. The ozone molecule number density is calculated fr om the differential absorption of the anti-Stokes rotational Raman return s ignals from molecular nitrogen and oxygen as the on-resonance wavelength an d the vibrational-rotational Raman backscattering from molecular nitrogen o r oxygen as the off-resonance wavelength. Model calculations show that the main advantage of the new rotational vibrational-rotational (RVR) Raman DIA L over conventional Raman DIAL is a 70-85% reduction in the wavelength-depe ndent effects of cloud-particle scattering on the measured ozone concentrat ion; furthermore the complexity of the apparatus is reduced substantially. We describe a RVR Raman DIAL setup that uses a narrow-band interference-fil ter polychromator as the lidar receiver. Single-laser ozone measurements in the troposphere and lower stratosphere are presented, and it is shown that on further improvement of the receiver performance, ozone measurements in clouds are attainable with the filter-polychromator approach. (C) 2000 Opti cal Society of America OCIS codes: 010.3640, 280.1910, 290.5860, 010.4950, 290.1090, 290.4210.