Sensing Full Atmospheric Aerosol and Wind Profiles Using Quadrature Mach Zehnder Interferometry Lidar

Abstract:

Space-based atmospheric lidar systems, including CALIPSO (operating over 14 years on orbit) and ESA’s Aeolus Wind lidar mission (entering its 3^rd year of operation), have provided valuable aerosol and wind profiles for improving our understanding of Earth’s dynamic atmospheric processes. Building on these missions, new lidar technologies need to reduce cost and risk while increasing capability. Multi-function, quadrature Mach-Zehnder interferometer (QMZI) lidars can be configured to provide high spectral resolution lidar (HSRL) aerosol backscatter measurements and winds from aerosol returns, or to provide wind measurements using both narrow-band aerosol and wide-band molecular backscattered returns, enabling full atmospheric (planetary boundary layer through the lower stratosphere) profiling. By measuring relative changes in both fringe amplitude (aerosol signal) and fringe phase (Doppler wind signal) of atmospheric returns in these four-channel interferometers, strict stability requirements on the laser frequency, interferometer receiver, and platform pointing are significantly reduced or eliminated. We present examples of the highly flexible QMZI approach demonstrated in Optical Autocovariance Wind Lidar (OAWL) systems at Ball, and we discuss several benefits of using QMZI to reduce system risk and cost while providing both HSRL and Doppler wind observations for future Earth and other planetary (e.g. Mars, Titan) orbiting lidar missions.