Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.400 IF 3.400
  • IF 5-year value: 3.841 IF 5-year
    3.841
  • CiteScore value: 3.71 CiteScore
    3.71
  • SNIP value: 1.472 SNIP 1.472
  • IPP value: 3.57 IPP 3.57
  • SJR value: 1.770 SJR 1.770
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 70 Scimago H
    index 70
  • h5-index value: 49 h5-index 49
Volume 8, issue 10
Atmos. Meas. Tech., 8, 4111-4122, 2015
https://doi.org/10.5194/amt-8-4111-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Atmos. Meas. Tech., 8, 4111-4122, 2015
https://doi.org/10.5194/amt-8-4111-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 07 Oct 2015

Research article | 07 Oct 2015

Use of rotational Raman measurements in multiwavelength aerosol lidar for evaluation of particle backscattering and extinction

I. Veselovskii1, D. N. Whiteman2, M. Korenskiy1,4, A. Suvorina1, and D. Pérez-Ramírez2,3 I. Veselovskii et al.
  • 1Physics Instrumentation Center of General Physics Institute, Troitsk, Moscow, Russia
  • 2NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 3Universities Space Research Association, Columbia, MD, USA
  • 4Far Eastern Federal University, Russia

Abstract. Vibrational Raman scattering from nitrogen is commonly used in aerosol lidars for evaluation of particle backscattering (β) and extinction (α) coefficients. However, at mid-visible wavelengths, particularly in the daytime, previous measurements have possessed low signal-to-noise ratio. Also, vibrational scattering is characterized by a significant frequency shift of the Raman component, so for the calculation of α and β information about the extinction Ångström exponent is needed. Simulation results presented in this study demonstrate that ambiguity in the choice of Ångström exponent can be the a significant source of uncertainty in the calculation of backscattering coefficients when optically thick aerosol layers are considered. Both of these issues are addressed by the use of pure-rotational Raman (RR) scattering, which is characterized by a higher cross section compared to nitrogen vibrational scattering, and by a much smaller frequency shift, which essentially removes the sensitivity to changes in the Ångström exponent. We describe a practical implementation of rotational Raman measurements in an existing Mie–Raman lidar to obtain aerosol extinction and backscattering at 532 nm. A 2.3 nm width interference filter was used to select a spectral range characterized by low temperature sensitivity within the anti-Stokes branch of the RR spectrum. Simulations demonstrate that the temperature dependence of the scattering cross section does not exceed 1.5 % in the 230–300 K range, making correction for this dependence quite easy. With this upgrade, the NASA GSFC multiwavelength Raman lidar has demonstrated useful α532 measurements and was used for regular observations. Examples of lidar measurements and inversion of optical data to the particle microphysics are given.

Publications Copernicus
Download
Short summary
We describe a practical implementation of rotational Raman (RR) measurements in an existing Mie-Raman lidar to obtain aerosol extinction and backscattering at 532nm. A 2.3nm width interference filter was used to select a spectral range characterized by low temperature sensitivity within the anti-Stokes branch of the RR spectrum. Simulations demonstrate that the temperature dependence of the scattering cross section does not exceed 1.5% in the 230-300K range.
We describe a practical implementation of rotational Raman (RR) measurements in an existing...
Citation
Share