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Title: LOSA-M2 aerosol Raman lidar

Abstract

The scanning LOSA-M2 aerosol Raman lidar, which is aimed at probing atmosphere at wavelengths of 532 and 1064 nm, is described. The backscattered light is received simultaneously in two regimes: analogue and photon-counting. Along with the signals of elastic light scattering at the initial wavelengths, a 607-nm Raman signal from molecular nitrogen is also recorded. It is shown that the height range of atmosphere probing can be expanded from the near-Earth layer to stratosphere using two (near- and far-field) receiving telescopes, and analogue and photon-counting lidar signals can be combined into one signal. Examples of natural measurements of aerosol stratification in atmosphere along vertical and horizontal paths during the expeditions to the Gobi Desert (Mongolia) and Lake Baikal areas are presented.

Authors:
; ; ; ;  [1]
  1. V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation)
Publication Date:
OSTI Identifier:
22043663
Resource Type:
Journal Article
Resource Relation:
Journal Name: Quantum Electronics (Woodbury, N.Y.); Journal Volume: 41; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AEROSOLS; AIR POLLUTION CONTROL; ATMOSPHERES; DESERTS; LAKE BAIKAL; LAYERS; LIGHT SCATTERING; NITROGEN; OPTICAL RADAR; PHOTONS; QUANTUM ELECTRONICS; RAMAN EFFECT; TELESCOPES; VISIBLE RADIATION; WAVELENGTHS

Citation Formats

Balin, Yu S, Bairashin, G S, Kokhanenko, G P, Penner, I E, and Samoilova, S V. LOSA-M2 aerosol Raman lidar. United States: N. p., 2011. Web. doi:10.1070/QE2011V041N10ABEH014574.
Balin, Yu S, Bairashin, G S, Kokhanenko, G P, Penner, I E, & Samoilova, S V. LOSA-M2 aerosol Raman lidar. United States. doi:10.1070/QE2011V041N10ABEH014574.
Balin, Yu S, Bairashin, G S, Kokhanenko, G P, Penner, I E, and Samoilova, S V. 2011. "LOSA-M2 aerosol Raman lidar". United States. doi:10.1070/QE2011V041N10ABEH014574.
@article{osti_22043663,
title = {LOSA-M2 aerosol Raman lidar},
author = {Balin, Yu S and Bairashin, G S and Kokhanenko, G P and Penner, I E and Samoilova, S V},
abstractNote = {The scanning LOSA-M2 aerosol Raman lidar, which is aimed at probing atmosphere at wavelengths of 532 and 1064 nm, is described. The backscattered light is received simultaneously in two regimes: analogue and photon-counting. Along with the signals of elastic light scattering at the initial wavelengths, a 607-nm Raman signal from molecular nitrogen is also recorded. It is shown that the height range of atmosphere probing can be expanded from the near-Earth layer to stratosphere using two (near- and far-field) receiving telescopes, and analogue and photon-counting lidar signals can be combined into one signal. Examples of natural measurements of aerosol stratification in atmosphere along vertical and horizontal paths during the expeditions to the Gobi Desert (Mongolia) and Lake Baikal areas are presented.},
doi = {10.1070/QE2011V041N10ABEH014574},
journal = {Quantum Electronics (Woodbury, N.Y.)},
number = 10,
volume = 41,
place = {United States},
year = 2011,
month =
}
  • Aerosol backscattering and extinction profiles measured by the NASA Goddard Space Flight Center Scanning Raman Lidar (SRL) during the remote cloud sensing (RCS) intensive operations period (IOP) at the Department of Energy Atmospheric Radiation Measurement (ARM) southern Great Plains (SGP) site during two nights in April 1994 are discussed. These profiles are shown to be consistent with the simultaneous aerosol size distribution measurements made by a PCASP (Passive Cavity Aerosol Spectrometer Probe) optical particle counter flown on the University of North Dakota Citation aircraft. We describe a technique which uses both lidar and PCASP measurements to derive the dependence ofmore » particle size on relative humidity, the aerosol real refractive index {ital n}, and estimate the effective single-scattering albedo {omega}{sub 0}. Values of {ital n} ranged between 1.4{endash}1.5 (dry) and 1.37{endash}1.47 (wet); {omega}{sub 0} varied between 0.7 and 1.0. The single-scattering albedo derived from this technique is sensitive to the manner in which absorbing particles are represented in the aerosol mixture; representing the absorbing particles as an internal mixture rather than the external mixture assumed here results in generally higher values of {omega}{sub 0}. The lidar measurements indicate that the change in particle size with relative humidity as measured by the PCASP can be represented in the form discussed by {ital Hanel} [1976] with the exponent {gamma}=0.3{plus_minus}0.05. The variations in aerosol optical and physical characteristics captured in the lidar and aircraft size distribution measurements are discussed in the context of the meteorological conditions observed during the experiment. {copyright} 1998 American Geophysical Union« less
  • A combined Raman elastic-backscatter lidar is utilized to observe the development of the stratospheric perturbation after the strong eruptions of Mount Pinatubo in June 1991. Height profiles of the particle extinction and backscatter coefficients are determined simultaneously and independently of each other. From these data the area-weighted mean particle radius and the aerosol surface area and mass are determined. The lidar measurements are taken at Geesthacht in northern Germany (53.5[degree]N, 10.5[degree]E). The Pinatubo aerosol layer is located between the tropopause and about 24 km height. Traces of stratospheric aerosol were frequently found down to 5 km height. The optical depthmore » of the stratospheric aerosol layer has been of the order of 0.15 in 1992. The ratio of optical depth to column-integrated backscatter varied between about 15 and 60 sr. Most values were found between 20 and 30 sr. Extinction-to-backscatter ratios >50, between 20 and 30, and <15sr indicate effective particle radii <0.2, between 0.2 and 0.75, and >0.75 [mu]m, respectively, as Mie scattering calculations show. Variations of the extinction-to-backscatter ratio with height between about 10 and 99 sr were observed. Column aerosol mass and surface area were of the order of 0.05 gm[sup [minus]2] and 2.5 [times] 10[sup 11] [mu]m[sup 2] m[sup [minus]2] in the first half of 1992. 7 refs., 4 figs.« less
  • This paper examines the aerosol backscattering and extinction profiles measured at night by the NASA Goddard Space Flight Center Scanning Raman Lidar (SRL) during the remote cloud sensing (RCS) intensive operations period (IOP) at the Department of Energy Atmospheric Radiation Measurement (ARM) southern Great Plains (SGP) site in April 1994. These lidar data are used to derive aerosol profiles for altitudes between 0.015 and 5 km. Since this lidar detects Raman scattering from nitrogen and oxygen molecules as well as the elastic scattering from molecules and aerosols, it measures both aerosol backscattering and extinction simultaneously. The aerosol extinction/backscattering ratio variedmore » between approximately 30 sr and 75 sr at 351 nm. Aerosol optical thicknesses derived by integrating the lidar profiles of aerosol extinction measured at night between 0.1 and 5 km are found to be about 10{endash}40{percent} lower than those measured by a Sun photometer during the day. This difference is attributed to the contribution by stratospheric aerosols not included in the lidar estimates as well as to diurnal differences in aerosol properties and concentrations. Aerosol profiles close to the surface were acquired by pointing the lidar nearly horizontally. Measurements of aerosol scattering from a tower-mounted nephelometer are found to be 40{percent} lower than lidar measurements of aerosol extinction over a wide range of relative humidities even after accounting for the difference in wavelengths. The reasons for this difference are not clear but may be due to the inability of the nephelometer to accurately measure scattering by large particles. {copyright} 1998 American Geophysical Union« less
  • A Feature detection and EXtinction retrieval (FEX) algorithm for the Atmospheric Radiation Measurement (ARM) program’s Raman lidar (RL) has been developed. Presented here is part 1 of the FEX algorithm: the detection of features including both clouds and aerosols. The approach of FEX is to use multiple quantities— scattering ratios derived using elastic and nitro-gen channel signals from two fields of view, the scattering ratio derived using only the elastic channel, and the total volume depolarization ratio— to identify features using range-dependent detection thresholds. FEX is designed to be context-sensitive with thresholds determined for each profile by calculating the expectedmore » clear-sky signal and noise. The use of multiple quantities pro-vides complementary depictions of cloud and aerosol locations and allows for consistency checks to improve the accuracy of the feature mask. The depolarization ratio is shown to be particularly effective at detecting optically-thin features containing non-spherical particles such as cirrus clouds. Improve-ments over the existing ARM RL cloud mask are shown. The performance of FEX is validated against a collocated micropulse lidar and observations from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite over the ARM Darwin, Australia site. While we focus on a specific lidar system, the FEX framework presented here is suitable for other Raman or high spectral resolution lidars.« less
  • We derive profiles of the aerosol extinction-to-backscatter ratio, Sa, at 355 nm using aerosol extinction and backscatter profiles measured during 1998 and 1999 by the operational Raman lidar at the Department of Energy Atmospheric Radiation Measurement program Southern Great Plains site in north central Oklahoma. Data from this Raman/Rayleigh-Mie lidar, which measures Raman scattering from nitrogen as well as the combined molecular (Rayleigh) and aerosol (Mie) scattering at the laser wavelength, are used to derive aerosol extinction and backscattering independently as a function of altitude. Because this lidar operates at 355 nm, where molecular backscattering is comparable with aerosol backscattering,more » Sa retrievals are generally limited to conditions where the aerosol extinction at 355 nm is > 0.03 km-1. The mean value of Sa at 355 nm derived for this period was 60 sr with a standard deviation of 12 sr. Sa was generally about 5-10 sr higher during high aerosol optical thickness (AOT) (> 0.3) conditions than during low AOT (< 0.1). A similar increase in Sa was found when the relative humidity increased from 30 to 80%. Large (> 15%) variations in the vertical profile of Sa occurred about 30% of the time, which implies significant variability in the vertical distribution of aerosol size distribution, shape, and/or composition often occurs. The Raman lidar measurements of Sa were compared with estimates of particle size and refractive index derived from an algorithm that uses ground-based Sun photometer measurements of Sun and sky radiance. For 17 cases of coincident Raman lidar and Sun and sky radiance measurements, Sa was linearly correlated with the aerosol fine mode effective radius and the volume ratio of fine/coarse particles.« less