A Comparative Analysis of Aerosol Optical Coefficients and Their Associated Errors Retrieved from Pure-Rotational and Vibro-Rotational Raman Lidar Signals
Open Access
- 11 February 2021
- Vol. 21 (4), 1277
- https://doi.org/10.3390/s21041277
Abstract
This paper aims to quantify the improvement obtained with a purely rotational Raman (PRR) channel over a vibro-rotational Raman (VRR) channel, used in an aerosol lidar with elastic and Raman channels, in terms of signal-to-noise ratio (SNR), effective vertical resolution, and absolute and relative uncertainties associated to the retrieved aerosol optical (extinction and backscatter) coefficients. Measurements were made with the European Aerosol Research Lidar Network/Universitat Politècnica de Catalunya (EARLINET/UPC) multi-wavelength lidar system enabling a PRR channel at 353.9 nm, together with an already existing VRR (386.7 nm) and an elastic (354.7 nm) channels. Inversions were performed with the EARLINET Single Calculus Chain (SCC). When using PRR instead of VRR, the measurements show a gain in SNR of a factor 2.8 and about 7.6 for 3-h nighttime and daytime measurements, respectively. For 3-h nighttime (daytime) measurements the effective vertical resolution is reduced by 17% (20%), the absolute uncertainty (associated to the extinction) is divided by 2 (10) and the relative uncertainty is divided by 3 (7). During daytime, VRR extinction coefficient is retrieved in a limited height range (<2.2 km) preventing the SCC from finding a suitable calibration range in the search height range. So the advantage of using PRR instead of VRR is particularly evidenced in daytime conditions. For nighttime measurements, decreasing the time resolution from 3 to 1 h has nearly no effect on the relative performances of PRR vs. VRR.Keywords
Funding Information
- Horizon 2020 (654109, 778349, 871115)
- Ministerio de Ciencia e Innovación (PID2019-103886RB-I00, CGL2017-90884-REDT)
- Agencia Estatal de Investigación (MDM-2016-0600)
This publication has 29 references indexed in Scilit:
- Rotational Raman Lidar: Design and Performance Test of Meteorological Parameters (Aerosol Backscattering Coefficients and Temperature)Journal of the Korean Physical Society, 2007
- Vibration rotation Raman spectroscopy of gas mediaSpectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 1996
- An Interior Trust Region Approach for Nonlinear Minimization Subject to BoundsSIAM Journal on Optimization, 1996
- On the convergence of interior-reflective Newton methods for nonlinear minimization subject to boundsMathematical Programming, 1994
- Measurement of atmospheric aerosol extinction profiles with a Raman lidarOptics Letters, 1990
- Lidar Observations of Vertically Organized Convection in the Planetary Boundary Layer over the OceanJournal of Climate and Applied Meteorology, 1985
- Measurement of the dispersion in polarizability anisotropiesThe Journal of Chemical Physics, 1975
- Laser-Raman radar ?Laser-Raman scattering methods for remote detection and analysis of atmospheric pollutionOptical and Quantum Electronics, 1972
- Gas Phase Raman Intensities: A Review of “Pre-Laser” DataApplied Spectroscopy, 1969
- On the Exact Variance of ProductsJournal of the American Statistical Association, 1960