Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar

• Published in: Journal of atmospheric and oceanic technology 2010-11, Vol.27 (11), p.1781-1801
• Main Authors: Whiteman, David N., Rush, Kurt, Rabenhorst, Scott, Welch, Wayne, Cadirola, Martin, McIntire, Gerry, Russo, Felicita, Adam, Mariana, Venable, Demetrius, Connell, Rasheen, Veselovskii, Igor, Forno, Ricardo, Mielke, Bernd, Stein, Bernhard, Leblanc, Thierry, McDermid, Stuart, Voemel, Holger
• Format: Article
• Language: English
• Subjects: Aerosols; Aircraft; Clouds; Data processing; Droplets; Extinction; Instrumentation; Lasers; Lidar; Marine; Mathematical models; Meteorology; Meteorology And Climatology; Mountains; Stratosphere; Water vapor
• ISSN: 0739-0572; 1520-0426
• DOI: 10.1175/2010JTECHA1391.1

A high-performance Raman lidar operating in the UV portion of the spectrum has been used to acquire, for the first time using a single lidar, simultaneous airborne profiles of the water vapor mixing ratio, aerosol backscatter, aerosol extinction, aerosol depolarization and research mode measurements of cloud liquid water, cloud droplet radius, and number density. The Raman Airborne Spectroscopic Lidar (RASL) system was installed in a Beechcraft King Air B200 aircraft and was flown over the mid-Atlantic United States during July August 2007 at altitudes ranging between 5 and 8 km. During these flights, despite suboptimal laser performance and subaperture use of the telescope, all RASL measurement expectations were met, except that of aerosol extinction. Following the Water Vapor Validation Experiment Satellite/Sondes (WAVES_2007) field campaign in the summer of 2007, RASL was installed in a mobile trailer for groundbased use during the Measurements of Humidity and Validation Experiment (MOHAVE-II) field campaign held during October 2007 at the Jet Propulsion Laboratory s Table Mountain Facility in southern California. This ground-based configuration of the lidar hardware is called Atmospheric Lidar for Validation, Interagency Collaboration and Education (ALVICE). During theMOHAVE-II field campaign, during which only nighttime measurements were made, ALVICE demonstrated significant sensitivity to lower-stratospheric water vapor. Numerical simulation and comparisons with a cryogenic frost-point hygrometer are used to demonstrate that a system with the performance characteristics of RASL ALVICE should indeed be able to quantify water vapor well into the lower stratosphere with extended averaging from an elevated location like Table Mountain. The same design considerations that optimize Raman lidar for airborne use on a small research aircraft are, therefore, shown to yield significant dividends in the quantification of lower-stratospheric water vapor. The MOHAVE-II measurements, along with numerical simulation, were used to determine that the likely reason for the suboptimal airborne aerosol extinction performance during theWAVES_2007 campaign was amisaligned interference filter. With full laser power and a properly tuned interference filter,RASL is shown to be capable ofmeasuring themain water vapor and aerosol parameters with temporal resolutions of between 2 and 45 s and spatial resolutions ranging from 30 to 330 m from a flight altitude of 8 km with precis