Measurement of Temperature and Aerosol to Molecule Ratio in the Troposphere by Optical Radar

Fiocco, G.; Benedetti-Michelangeli, G.; Maischberger, K.; Madonna, Erica

doi:10.1038/physci229078a0

Cited by 48 publications

(12 citation statements)

References 2 publications

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“…For an improvement concerning the parameterization process it is foreseen to utilize several Tenti S6 line shapes calculated for different wavelengths, scattering angles and temperature-and pressure values in order to find improved values for the parameters needed to evaluate Eq. (6). In case that this approach leads not to an improvement, a new approach can be explored based on deriving the analytical model for a fixed wavelength and scattering angle, just depending on temperature and pressure.…”

Section: Resultsmentioning

confidence: 99%

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Temperature retrieval from Rayleigh-Brillouin scattering profiles measured in air

Witschas¹,

Gu²,

Ubachs³

2014

Opt. Express

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In order to investigate the performance of two different algorithms for retrieving temperature from Rayleigh-Brillouin (RB) line shapes, RB scattering measurements have been performed in air at a wavelength of 403 nm, for a temperature range from 257 K to 330 K, and atmospherically relevant pressures from 871 hPa to 1013 hPa. One algorithm, based on the Tenti S6 line shape model, shows very good accordance with the reference temperature. In particular, the absolute difference is always less than 2 K. A linear correlation yields a slope of 1.01 ± 0.02 and thus clearly demonstrates the reliability of the retrieval procedure. The second algorithm, based on an analytical line shape model, shows larger discrepancies of up to 9.9 K and is thus not useful at its present stage. The possible reasons for these discrepancies and improvements of the analytical model are discussed. The obtained outcomes are additionally verified with previously performed RB measurements in air, at 366 nm, temperatures from 255 K to 338 K and pressures from 643 hPa to 826 hPa [Appl. Opt. 52, 4640 (2013)]. The presented results are of relevance for future lidar studies that might utilize RB scattering for retrieving atmospheric temperature profiles with high accuracy.

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Section: Resultsmentioning

confidence: 99%

“…The narrow RB line width of a few GHz additionally enables the application of narrow band filters to suppress solar radiation and thus allows for daytime operation. This approach was already suggested and demonstrated in 1971 by Fiocco et al [6], although their experimental data were severely contaminated by Mie scattering.…”

Section: Introductionmentioning

confidence: 89%

Temperature retrieval from Rayleigh-Brillouin scattering profiles measured in air

Witschas¹,

Gu²,

Ubachs³

2014

Opt. Express

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“…This figure suggests that the lidar ratio for smoke particles under investigation is a function of the age of the particles. In general, the lidar ratio can be calculated by Raman lidars that can perform independent measurement of backscatter and extinction profiles (Ansmann et al, 1992) and High Spectral Resolution Lidars (HSRL) (Fiocco et al, 1971). However, most lidars used in aerosol research are elastic-backscatter lidars and in that case, the lidar ratio is an important parameter for the determination of the particle backscatter coefficient from the elastic-backscatter signal alone.…”

Section: Resultsmentioning

confidence: 99%

Optical characteristics of biomass burning aerosols over Southeastern Europe determined from UV-Raman lidar measurements

Amiridis¹,

Balis²,

Giannakaki³

et al. 2008

Preprint

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The influence of smoke on the aerosol loading in the free troposphere over Thessaloniki, Greece is examined in this paper. Ten cases during 2001-2005 were identified when very high aerosol optical depth values in the free troposphere were observed with a UV-Raman lidar. Particle dispersion modeling (FLEXPART) and satellite hot spot fire detection (ATSR) showed that these high free tropospheric aerosol optical depths are mainly attributed to the advection of smoke plumes from biomass burning regions over Thes-saloniki. The biomass burning regions were found to extend across Russia in the latitudinal belt between 45 • N-55 • N, as well as in Eastern Europe (Baltic countries, Western Russia, Belarus, and the Ukraine). The highest frequency of agricultural fires occurred during the summer season (mainly in August). The data collected allowed the optical characterization of the smoke aerosols that arrived over Greece, where limited information has so far been available. Two-wavelength backscatter lidar measurements showed that the backscatter-relatedÅngströmrelated˚relatedÅngström exponent ranged between 0.5 and 2.4 indicating a variety of particle sizes. UV-Raman lidar measurements showed that for smoke particles the extinction to backscatter ratios (so-called lidar ratios) varied between 40 sr for small particles to 100 sr for large particles. Dispersion model estimations of the carbon monoxide tracer concentration profiles for smoke particles indicate that the variability of the optical parameters is a function of the age of the smoke Correspondence to: V. Amiridis (vamoir@space.noa.gr) plumes. This information could be useful on the lidar community for reducing uncertainty in the aerosol backscatter coefficient determination due to the lidar ratio assumption, starting from a simply elastic backscatter lidar as the first satellite-borne lidar CALIPSO.

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“…On the one hand, the entire Cabannes line (more precisely, the sum of the Laudau-Placzek line and the Brillouin doublet) is obtained by scanning either the Fabry-Perot interferometer (FPI) or the laser. Then the temperature is calculated from the fitted linewidth of the Cabannes line [23,24]. On the other hand, the lidar signal is measured before and passing through a static filter, for instance, a fixed FPI, Michelson interferometers, atomic or molecular absorption cells.…”

Section: Introductionmentioning

confidence: 99%

Stratospheric temperature measurement with scanning Fabry-Perot interferometer for wind retrieval from mobile Rayleigh Doppler lidar

et al. 2014

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Temperature detection remains challenging in the low stratosphere, where the Rayleigh integration lidar is perturbed by aerosol contamination and ozone absorption while the rotational Raman lidar is suffered from its low scattering cross section. To correct the impacts of temperature on the Rayleigh Doppler lidar, a high spectral resolution lidar (HSRL) based on cavity scanning Fabry-Perot Interferometer (FPI) is developed. By considering the effect of the laser spectral width, Doppler broadening of the molecular backscatter, divergence of the light beam and mirror defects of the FPI, a well-behaved transmission function is proved to show the principle of HSRL in detail. Analysis of the statistical error of the HSRL is carried out in the data processing. A temperature lidar using both HSRL and Rayleigh integration techniques is incorporated into the Rayleigh Doppler wind lidar. Simultaneous wind and temperature detection is carried out based on the combined system at Delhi (37.371°N, 97.374°E; 2850 m above the sea level) in Qinghai province, China. Lower Stratosphere temperature has been measured using HSRL between 18 and 50 km with temporal resolution of 2000 seconds. The statistical error of the derived temperatures is between 0.2 and 9.2 K. The temperature profile retrieved from the HSRL and wind profile from the Rayleigh Doppler lidar show good agreement with the radiosonde data. Specifically, the max temperature deviation between the HSRL and radiosonde is 4.7 K from 18 km to 36 km, and it is 2.7 K between the HSRL and Rayleigh integration lidar from 27 km to 34 km.

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Measurement of Temperature and Aerosol to Molecule Ratio in the Troposphere by Optical Radar

Cited by 48 publications

References 2 publications

Temperature retrieval from Rayleigh-Brillouin scattering profiles measured in air

Temperature retrieval from Rayleigh-Brillouin scattering profiles measured in air

Optical characteristics of biomass burning aerosols over Southeastern Europe determined from UV-Raman lidar measurements

Stratospheric temperature measurement with scanning Fabry-Perot interferometer for wind retrieval from mobile Rayleigh Doppler lidar

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