Preprints
https://doi.org/10.5194/amt-2021-307
https://doi.org/10.5194/amt-2021-307

  14 Oct 2021

14 Oct 2021

Review status: this preprint is currently under review for the journal AMT.

Retrieval of UVB aerosol extinction profiles from the ground-based Langley Mobile Ozone Lidar (LMOL) system

Liqiao Lei1,2, Timothy A. Berkoff2, Guillaume P. Gronoff2,3, Jia Su4, Amin R. Nehrir2, Yonghua Wu5,6, Fred Moshary5,6, and Shi Kuang7 Liqiao Lei et al.
  • 1Universities Space Research Association, Columbia, MD, USA
  • 2NASA Langley Research Center, Hampton, VA, USA
  • 3Science Systems and Applications, Hampton, VA, USA
  • 4Hampton University, Hampton, VA, USA
  • 5City College of New York (CCNY), New York, NY 10031, USA
  • 6NOAA – Cooperative Science Center for Earth System Sciences and Remote Sensing Technologies, USA
  • 7University of Alabama in Huntsville, Huntsville, Alabama, USA

Abstract. Aerosols emitted from wildfires are becoming one of the main sources of poor air quality in the US mainland. Their extinction in UVB (wavelength range 280–315 nm) is difficult to be retrieved using simple lidar techniques because of the impact of O3 absorption and lacking information of lidar ratio at those wavelengths. The 2018 Long Island Sound Tropospheric Ozone Study (LISTOS) campaign in the New York City region allowed the characterization of lidar ratio for UVB aerosol retrieval. An algorithm for the aerosol extinction retrieval out of the Langley Mobile Ozone Lidar (LMOL) was used in conjunction with the NASA Langley High Altitude Lidar Observatory (HALO) 532 nm aerosol extinction product. This approach requires assuming 2 parameters, the lidar ratio at 292 nm and the Ångström Exponent (AE) between 532 nm and 292 nm. The objective of this work is to determine these two parameters and assess the retrieval error caused by improper assumption of lidar ratio. This work also accomplishes the first know 292 nm aerosol product inter-comparison between HALO and Tropospheric Ozone Lidar Network (TOLNet) ozone lidar. HALO results were compared with the aerosol data retrieved from the 292 nm band from LMOL with different approximations of the lidar ratio and the AE to determine optimal parameters. Using optimized parameters, the LMOL aerosol extinction can be retrieved with a 10 % accuracy up to 3 km. This work highlights the importance of the lidar ratio and AE in the retrieval and validation of 292 nm aerosol profiles obtained from UV-lidar. Errors arise from approaches that utilize a random priori lidar ratio and AE assumption. The lidar ratios at 292 nm determined in this work will also improve our understanding of the UVB optical properties of aerosol in the lower troposphere affected by transported wildfire emission.

Liqiao Lei et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on amt-2021-307', Anonymous Referee #1, 12 Nov 2021
  • RC2: 'Comment on amt-2021-307', Anonymous Referee #2, 15 Nov 2021

Liqiao Lei et al.

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Short summary
Aerosol extinction coefficient at 292 nm was retrieved by using the Langley Mobile Ozone Lidar (LMOL) data. The lidar ratio, which is a very important parameter for lidar aerosol extinction retrieval, was determined using a method which combine the O3 lidar data and NASA Langley High Altitude Lidar Observatory (HALO) aerosol data. The Angstrom Exponent (532 and 292 nm) were also determined at the same time. We also accomplish the 292 nm aerosol product inter-comparison between HALO and LMOL.