Design of a Combined High Spectral Resolution and Oxygen Differential Absorption Lidar for Measuring Atmospheric Temperature

Differential absorption lidar (DIAL) has been successfully implemented to measure mixing ratios of atmospheric gases such as water vapor, carbon dioxide, and methane. Less success has been found, however, in trying to use DIAL systems to measure atmospheric temperature. Several attempts, made more than 20 years ago, to measure atmospheric temperature using DIAL systems based on oxygen absorption have concluded that useful accuracy of temperature measurements was not possible. Diode laser based lidar technology and new retrieval techniques, under development by Montana State University and the National Center for Atmospheric Research, show promise to alleviate problems revealed in previous temperature profiling based on the DIAL technique by offering needed ancillary measurements of water vapor mixing ratio and aerosol and molecular backscatter profiles using low cost, multi-wavelength, narrowband, micro-pulse DIAL (MPD) instruments. These MPD instruments are field deployable and offer unattended continuous operation over time scales of weeks to months. A combined oxygen DIAL and high spectral resolution lidar (HSRL) system, both based on MPD technology, are currently being developed to address the dual requirement to measure temperature sensitive oxygen absorption and the quantitative atmospheric aerosol properties needed for accurate temperature retrievals. This presentation will describe progress towards developing a temperature measuring MPD system with useful accuracy for tropospheric studies.