Title of Paper: Raman Airborne Spectroscopic Lidar
Principal Author: Dr. David Whiteman
Abstract: Improved understanding of the dynamic and radiative properties of atmospheric water in all of its phases and of atmospheric aerosols and their influence on cloud properties are high priorities of the Earth Science Enterprise (ESE). The Raman Airborne Spectroscopic Lidar (RASL) is designed to address these and other high priority Earth Science Enterprise measurement requirements in a broader fashion than any other airborne lidar.
RASL is being developed as a part of the first Instrument Incubator Program to be compatible with such aircraft as the NASA DC-8 and P-3. It will be laboratory validated by March, 2002 to measure water vapor mixing ratio, aerosol scattering ratio, aerosol extinction, aerosol depolarization, cirrus cloud optical depth and cloud liquid water. A recently developed retrieval algorithm has demonstrated that these measurements can be used to also derive liquid cloud droplet radius and droplet number density. This combined set of measurements represents a revolution in airborne remote sensing of the atmosphere enabling studies of such important topics as the indirect aerosol effect to be studied.
We have proposed to the second IIP to advance necessary technologies for airborne Raman lidar. We propose fundamental research and development in the technology of UV interference filters which are needed for RASL measurements. We also propose the development of the necessary flight-hardened technologies that will permit the first test flight of RASL. These technologies include automated bore-site alignment and laser thermal stabilization sub-systems. The successful flight test of RASL will bring to an airborne platform the broad range of Raman lidar measurement capability, during both the daytime and nighttime, that has formerly been limited to ground-based systems thus permitting a wide range of ESE science questions to be addressed.