The Development of New Techniques For Remote Measurements of Atmospheric Gases

Abstract

The differential absorption lidar (DIAL) technique potentially has the ability to measure a wide range of atmospheric gases and industrial pollutants. The mobile DIAL facility developed at the National Physical Laboratory (NPL) is capable of range-resolved measurements of gases such as SO2, NO, NO2 and O3 in the troposphere [1] using visible and ultraviolet radiation. However, there is widespread interest in measuring a much broader range of gaseous pollutants which are emitted in industrial processes. These gases generally have absorption spectra in the infrared spectral region (wavelength range 2–15 μm), where DIAL measurements are much more difficult to carry out. Research aimed at developing a high-energy tunable infrared DIAL source for this requirement is outlined below. The wavelength coverage of the ultraviolet source in the DIAL facility has also been extended to address different atmospheric gases, and examples of results obtained using the NPL simultaneous infrared/ultraviolet DIAL system will be presented.