Characterizing the vertical distribution of aerosols using multiwavelength lidar data: Initial results from the CHARMS study at SGP
Authors
Richard A. Ferrare — NASA - Langley Research Center
Tyler Thorsen — NASA - Langley Research Center
Marian B. Clayton — Science Systems and Applications, Inc. (SSAI)
Detlef Mueller — Science Systems and Applications, Inc.
Eduard Chemyakin — Science Systems and Applications, Inc.
John E. M. Goldsmith — Sandia National Laboratories
Robert E. Holz — University of Wisconsin/CIMMS
Ralph Kuehn — University of Wisconsin Madison
Edwin W. Eloranta — University of Wisconsin
Rob K Newsom — Pacific Northwest National Laboratory
Sharon P Burton — NASA - Langley Research Center
Patricia Sawamura — Oak Ridge Associated Universities/NASA Langley Research Cent
Connor J. Flynn — University of Oklahoma School of Meteorology
Category
General topics – Aerosols
Description
Figure 1. CHARMS Raman lidar and HSRL measurements on August 1, 2015.
Observations of aerosol optical and microphysical properties are critical for developing and evaluating aerosol transport model parameterizations and assessing global aerosol-radiation impacts on climate. During the Combined HSRL And Raman lidar Measurement Study (CHARMS), researchers funded by DOE ARM investigated the synergistic use of ground-based SGP Raman lidar and High Spectral Resolution Lidar (HSRL) measurements to improve the capability of ARM to measure aerosol properties aloft. Continuous (24/7) operation of these co-located lidars during the ten-week CHARMS mission (mid-July through September 2015) allowed the acquisition of a unique, multiwavelength ground-based lidar dataset for studying the vertical distribution of aerosol properties above the SGP. The ARM Raman lidar measured profiles of aerosol backscatter, extinction and depolarization at 355 nm as well as profiles of water vapor mixing ratio and temperature. The University of Wisconsin HSRL simultaneously measured profiles of aerosol backscatter, extinction and depolarization at 532 nm and aerosol backscatter at 1064 nm.
Recent advances in both lidar retrieval theory and algorithm development demonstrate that vertically-resolved retrievals using such lidar (“3β+2α”) measurements of aerosol backscatter at 355, 532 and 1064 nm and extinction at 355 and 532 nm can help constrain both the aerosol optical (e.g. complex refractive index, scattering, etc.) and microphysical properties (e.g. effective radius, concentrations). Based on this work, the NASA Langley Research Center (LaRC) HSRL group developed automated algorithms for retrieving aerosol optical and microphysical properties, demonstrated these retrievals using data from the unique NASA/LaRC airborne multiwavelength HSRL 2 system, and validated the results using coincident airborne in situ data. We are now investigating the feasibility of applying these algorithms to the CHARMS multiwavelength (Raman+HSRL) lidar dataset to retrieve aerosol properties above the SGP site.
In this presentation, we discuss the CHARMS aerosol measurements and their suitability for use in these aerosol retrieval algorithms. We examine how the CHARMS measurements complement other SGP aerosol measurements and how they compare to measurements acquired by the NASA airborne multiwavelength HSRL during various NASA and DOE campaigns. We present some preliminary profile retrievals of aerosol effective radius and concentration derived from the CHARMS data.
