Lidar inversion with variable backscatter/extinction ratios

Klett, James D.

doi:10.1364/ao.24.001638

Cited by 852 publications

(569 citation statements)

References 3 publications

Supporting

Mentioning

541

Contrasting

Unclassified

Order By: Relevance

“…Optical filters of the P-MPL receiving system present a spectral band lower than 0.2 nm (Sigma Space Corporation, 2012), producing a temperature-independent δ mol of 0.00363 according to Behrendt and Nakamura (2002). The particle backscatter coefficient β p is obtained by applying the Klett-Fernald (KF) algorithm (Fernald, 1984;Klett, 1985) to P (= P || + P ⊥ ) profiles obtained from P-MPL measurements in synergy with simultaneous sun-photometer measurements that provide ancillary data of the aerosol optical depth (AOD). Hence, a vertically averaged lidar ratio (LR, extinction-tobackscatter ratio, denoted by S a ) can also be estimated by using this KF iterative approach in P-MPL measurements, since the LR value varies in each iteration, reaching convergence once the relative difference between the lidarderived height-integrated particle extinction profile…”

Section: Polarized Micro-pulse Lidar (P-mpl) Systemmentioning

confidence: 99%

Separation of the optical and mass features of particle components in different aerosol mixtures by using POLIPHON retrievals in synergy with continuous polarized Micro-Pulse Lidar (P-MPL) measurements

et al. 2018

View full text Add to dashboard Cite

Abstract. The application of the POLIPHON (POlarizationLIdar PHOtometer Networking) method is presented for the first time in synergy with continuous 24/7 polarized MicroPulse Lidar (P-MPL) measurements to derive the vertical separation of two or three particle components in different aerosol mixtures, and the retrieval of their particular optical properties. The procedure of extinction-to-mass conversion, together with an analysis of the mass extinction efficiency (MEE) parameter, is described, and the relative mass contribution of each aerosol component is also derived in a further step. The general POLIPHON algorithm is based on the specific particle linear depolarization ratio given for different types of aerosols and can be run in either 1-step (POL-1) or 2 steps (POL-2) versions with dependence on either the 2-or 3-component separation. In order to illustrate this procedure, aerosol mixing cases observed over Barcelona (NE Spain) are selected: a dust event on 5 July 2016, smoke plumes detected on 23 May 2016 and a pollination episode observed on 23 March 2016. In particular, the 3-component separation is just applied for the dust case: a combined POL-1 with POL-2 procedure (POL-1/2) is used, and additionally the fine-dust contribution to the total fine mode (fine dust plus non-dust aerosols) is estimated. The high dust impact before 12:00 UTC yields a mean mass loading of 0.6 ± 0.1 g m −2 due to the prevalence of Saharan coarse-dust particles. After that time, the mean mass loading is reduced by two-thirds, showing a rather weak dust incidence. In the smoke case, the arrival of fine biomass-burning particles is detected at altitudes as high as 7 km. The smoke particles, probably mixed with less depolarizing non-smoke aerosols, are observed in air masses, having their origin from either North American fires or the Arctic area, as reported by HYSPLIT backtrajectory analysis. The particle linear depolarization ratio for smoke shows values in the 0.10-0.15 range and even higher at given times, and the daily mean smoke mass loading is 0.017 ± 0.008 g m −2 , around 3 % of that found for the dust event. Pollen particles are detected up to 1.5 km in height from 10:00 UTC during an intense pollination event with a particle linear depolarization ratio ranging between 0.10 and 0.15. The maximal mass loading of Platanus pollen particles is 0.011 ± 0.003 g m −2 , representing around 2 % of the dust loading during the higher dust incidence. Regarding the MEE derived for each aerosol component, their values are in agreement with others referenced in the literature for the specific aerosol types examined in this work: 0.5 ± 0.1 and 1.7 ± 0.2 m 2 g −1 are found for coarse and fine dust particles, 4.5 ± 1.4 m 2 g −1 is derived for smoke and 2.4 ± 0.5 m 2 g −1 for non-smoke aerosols with Arctic origin, and a MEE of 2.4 ± 0.8 m 2 g −1 is obtained for pollen particles, though it can reach higher or lower values depending on predomiPublished by Copernicus Publications on behalf of the European Geosciences Union. 4776 C. Córdoba...

show abstract

Section: Polarized Micro-pulse Lidar (P-mpl) Systemmentioning

confidence: 99%

Separation of the optical and mass features of particle components in different aerosol mixtures by using POLIPHON retrievals in synergy with continuous polarized Micro-Pulse Lidar (P-MPL) measurements

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Calculation of backscatter (b aer ) and extinction (a aer ) was performed according to Ansmann et al (1992) with the lidar profiles of the mentioned resolution. The backscatter for the infrared (1064 nm) was evaluated according to Klett (1985) with the lidar ratio derived for the 532 nm channel. Finally, the aerosol depolarization (d aer ) at 532 nm was calculated from the both backscatter coefficients at parallel and perpendicular polarization according to Behrendt and Nakamura (2002 (Liu et al, 2002).…”

Section: Lidarmentioning

confidence: 99%

Springtime Arctic aerosol: Smoke versus haze, a case study for March 2008

Stock¹,

Ritter²,

Herber³

et al. 2012

Atmospheric Environment

View full text Add to dashboard Cite

a b s t r a c tDuring March 2008 photometer observations of Arctic aerosol were performed both at a Russian ice-floe drifting station (NP-35) at the central Arctic ocean (56.7e42.0 E, 85.5e84.2 N) and at Ny-Ålesund, Spitsbergen (78.9 N, 11.9 E). Next to a persistent increase of AOD over NP-35, two pronounced aerosol events have been recorded there, one originating from early season forest fires close to the city of Khabarovsk ("Arctic Smoke"), the other one showed trajectories from central Russia and resembled more the classical Arctic Haze. The latter event has also been recorded two days later over Ny-Ålesund, both in photometer and lidar. From these remote sensing instruments volume distribution functions are derived and discussed. Only subtle differences between the smoke and the haze event have been found in terms of particle microphysics. Different trajectory analysis, driven by NCEP and ECMWF have been performed and compared. For the data set presented here the meteorological field, due to sparseness of data in the central Arctic, mainly limits the precision of the air trajectories.

show abstract

“…As opposed to elastic instruments, Raman lidars have the advantage that the inelastic backscatter is only affected by aerosol extinction. Since the aerosol extinction of the atmosphere is measured with the inelastic backscatter (without relying on assumptions about the aerosol type), there is no need to estimate the lidar ratio for data analysis as required by the Klett approach (Klett, 1981(Klett, , 1985. This makes the Raman lidar approach superior to systems such as elastic lidars and ceilometers, where only the elastic backscatter is detected.…”

Section: Introductionmentioning

confidence: 99%