Sensitivity of the backscatter/extinction ratio to changes in aerosol properties: implications for lidar

Evans, B. T. N.

doi:10.1364/ao.27.003299

Cited by 44 publications

(24 citation statements)

References 21 publications

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“…Obviously, the most frequent value pairs are within a range of the particle linear depolarization ratio of 5-7 % and a range of the lidar ratio of 50-60 sr. 50 % of all measurement points show values of the particle linear depolarization ratio between 5 % and 7 % and a lidar ratio between 51 and 61 sr, and about 90 % of all measurement points show values between 4 % and 8 % of the particle linear depolarization ratio and between 48 sr and 65 sr of the lidar ratio. The median of the particle linear depolarization ratio is 6 %, of the lidar ratio 56 sr. Lidar ratios around and below 40 sr, found for about 5 % of all measurement points, may either indicate rural particles (Evans, 1988;Anderson et al, 2000) or mixtures with other aerosol types (e.g. clean continental aerosol or marine aerosol).…”

Section: Fig 8 (A)mentioning

confidence: 96%

“…The advantage of HSRL over normal backscatter-only lidar is the ability to directly measure the extinction-to-backscatter ratio (lidar ratio) of aerosols (Shipley et al, 1983;Shimizu et al, 1983). The value of this quantity depends on the physical properties of aerosols, namely the size distribution, the complex index of refraction and the morphology (Evans, 1988). It does not depend on its concentration.…”

Section: Introductionmentioning

confidence: 99%

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Airborne high spectral resolution lidar observation of pollution aerosol during EUCAARI-LONGREX

et al. 2013

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Airborne high spectral resolution lidar observations over Europe during the EUCAARI-LONGREX field experiment in May 2008 are analysed with respect to the optical properties of continental pollution aerosol. Continental pollution aerosol is characterized by its depolarisation and lidar ratio. Over all, the measurements of the lidar ratio and the particle linear depolarization ratio of pollution aerosols provide a narrow range of values. Therefore, this data set allows for a distinct characterization of the aerosol type "pollution aerosol" and thus is valuable both to distinguish continental pollution aerosol from other aerosol types and to determine mixtures with other types of aerosols

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Section: Fig 8 (A)mentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Airborne high spectral resolution lidar observation of pollution aerosol during EUCAARI-LONGREX

et al. 2013

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“…For this purpose the so-called Klett method [Klett, 1981;Fernald, 1984;Evans, 1988] is used. This method is less accurate because it requires the a priori assumption of the particle extinction-to-backscatter (lidar) ratio.…”

Section: Earlinet Raman Lidarmentioning

confidence: 99%

Saharan dust over a central European EARLINET‐AERONET site: Combined observations with Raman lidar and Sun photometer

et al. 2003

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Combined observations with an advanced aerosol water‐vapor temperature Raman lidar and a Sun photometer are used for a detailed characterization of geometrical and optical properties of a continental‐scale Saharan dust event observed over Leipzig (51.3°N, 12.4°E), Germany, from 13 to 15 October 2001. The Raman lidar is part of the European Aerosol Research Lidar Network (EARLINET). Automatic observations of aerosol optical depth and sky brightness are made with the Sun photometer in the framework of the worldwide operating Aerosol Robotic Network (AERONET). The dust plume reached a top height of 6000 m. Sun photometer and lidar observations showed a constant increase of columnar optical depth at 532 nm from 0.25 on 13 October 2001 to a maximum of ∼0.63 on 14 October 2001. According to observations with lidar, up to 90% of the optical depth at the wavelength of 532 nm was contributed by the dust layer above 1000‐m height. Ångström exponents from Sun photometer observations between 380 and 1020 nm were ∼0.45 at the beginning of the dust period, and dropped to minimum values of 0.14 during the peak of the dust outbreak. Vertically resolved Ångström exponents derived from lidar profiles of the extinction coefficients at 355 and 532 nm showed a strong variability with values as low as −0.2 in the center of the dust plume. Below 1000‐m height column‐averaged Ångström exponents strongly varied between 1.0 in the beginning of the dust period and 0.39 on 14 October 2001 when the dust penetrated into the boundary layer. Comparison of column‐averaged optical depth and Ångström exponents derived from lidar and Sun photometer observations showed excellent agreement. Particle depolarization ratios of up to 25% were derived from lidar observations at 532 nm. Scattering phase functions retrieved from Sun photometer observations indicated particles of nonspherical shape. This shape caused unusually large particle extinction‐to‐backscatter (lidar) ratios at 532 nm in the range from 50 to 80 sr. There were substantial deviations of the lidar ratio at 532 nm derived from both measurement methods. They are explained by the effect of particle shape.

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“…The AOD profile was inferrred using the assumption of a lidar ratio (extinction/backscattering) of 30 (Reagan et al, 1980;Ansmann et al, 1992). This typical value for rural aerosol (Evans, 1988) may be appropriate for the Egert site by reason of the relatively low AOD values recorded (see Fig. 8).…”

Section: Intercomparison Of Parameters With Other Methodsmentioning

confidence: 99%

Characterization of atmospheric aerosols across Canada from a ground‐based sunphotometer network: AEROCAN

et al. 2001

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Sensitivity of the backscatter/extinction ratio to changes in aerosol properties: implications for lidar

Cited by 44 publications

References 21 publications

Airborne high spectral resolution lidar observation of pollution aerosol during EUCAARI-LONGREX

Airborne high spectral resolution lidar observation of pollution aerosol during EUCAARI-LONGREX

Saharan dust over a central European EARLINET‐AERONET site: Combined observations with Raman lidar and Sun photometer

Characterization of atmospheric aerosols across Canada from a ground‐based sunphotometer network: AEROCAN

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