Lidar measurements of aerosol at Varanasi (25.28° N, 82.96° E), India during CAIPEEX scientific campaign
05 May 2016-Vol. 9876, pp 320-329
TL;DR: In this article, a dual-polarization lidar (DPL) was designed and developed at National Atmospheric Research Laboratory (NARL) for daytime measurements of the boundary layer aerosol distribution and depolarization properties with very high vertical and temporal resolution.
Abstract: A compact dual polarization lidar (DPL) was designed and developed at National Atmospheric Research Laboratory (NARL) for daytime measurements of the boundary layer aerosol distribution and depolarization properties with very high vertical and temporal resolution. The lidar employs a compact flashlamp pumped Q-switched Nd:YAG laser and operates at 532 nm wavelength. The lidar system uses a stable biaxial configuration between transmitter and receiver units. The receiver utilizes a 150 mm Schmidt Cassegranin telescope for collecting laser returns from the atmosphere. The collected backscattered light is separated into co and cross-polarization signals using a polarization beam splitter cube. A set of mini-PMTs have been used for detection of light from atmosphere during daylight period. A two channel transient recorder system with built-in ADC has been employed for recording the detected light. The entire lidar system is housed in a compact cabinet which can be easily transported for field measurements. During 2014, the lidar system was installed at the Banaras Hindu University (BHU) campus, Varanasi (25.28° N, 82.96° E, 82 m AMSL) and operated for a period of three months in to support the cloud aerosol interaction and precipitation enhancement experiment (CAIPEEX) conducted by Indian Institute of tropical meteorology (IITM). During this campaign period, the lidar measurements were carried out in the vertical direction with spatial resolution of 7.5 m and time sampling of 30s. The lidar measurements revealed the occurrence of boundary layer growth during convective periods and also detected the long-range transport dust layers with significant depolarization. In the present paper, we present the lidar measurements obtained during the campaign period and discuss the observation of transport of dust layer over the experimental site with support of back trajectory analysis and satellite data. The Lidar observations were compared with the available satellite observations also presented here.
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TL;DR: Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) is a two-wavelength polarization lidar that performs global profiling of aerosols and clouds in the troposphere and lower stratosphere as discussed by the authors.
Abstract: The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) is a two-wavelength polarization lidar that performs global profiling of aerosols and clouds in the troposphere and lower stratosphere. CALIOP is the primary instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite, which has flown in formation with the NASA A-train constellation of satellites since May 2006. The global, multiyear dataset obtained from CALIOP provides a new view of the earth’s atmosphere and will lead to an improved understanding of the role of aerosols and clouds in the climate system. A suite of algorithms has been developed to identify aerosol and cloud layers and to retrieve a variety of optical and microphysical properties. CALIOP represents a significant advance over previous space lidars, and the algorithms that have been developed have many innovative aspects to take advantage of its capabilities. This paper provides a brief overview of the CALIPSO mission, the CA...
1,833 citations
"Lidar measurements of aerosol at Va..." refers background in this paper
...The CALIPSO payload includes a high-powered digital camera, an infrared radiometer, and the two-wavelength (532 and 1064 nm) near-nadir, polarization sensitive elastic backscatter lidar CALIOP [11][12][13]....
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TL;DR: A restatement of the more general solution of Fernald et al.l which is also applicable to mildly turbid atmospheres where both aerosol and molecular scatterers must be considered in the analysis.
Abstract: There have been many discussions of solutions to the lidar equation for elastic scattering (e.g., Fernald et al.,' Klett, 2 Davis, and Collis and Russell ). Most of these are simply variations on Hitschfeld and Bordan's5 solution for meteorological radars. Klett 2 recently restated this solution in a very convenient form for the analysis of lidar observations collected in very turbid atmospheres. His paper has prompted a restatement of the more general solution of Fernald et al.l which is also applicable to mildly turbid atmospheres where both aerosol and molecular scatterers must be considered in the analysis. This has led to a simple numerical scheme for the computer analysis of lidar measurements. The lidar equation for two distinct classes of scatters (Fernald et al.') is
1,558 citations
"Lidar measurements of aerosol at Va..." refers background in this paper
...TDR is zero for spherical particles and deviates from zero for non-spherical particles [10]....
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...Depolarization facilitates the shape information of different particle types and can be defined [10]...
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TL;DR: In this article, the first time over land in the visible wavelengths by MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the EOSTerra spacecraft, the authors derived the aerosol optical depths from more than 30 AERONET (Aerosol Robotic Network) sites globally.
Abstract: Aerosol optical depths are derived operationally for the first time over land in the visible wavelengths by MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the EOSTerra spacecraft. More than 300 Sun photometer data points from more than 30 AERONET (Aerosol Robotic Network) sites globally were used in validating the aerosol optical depths obtained during July - September 2000. Excellent agreement is found with retrieval errors within (Delta)tau=+/- 0.05 +/- 0.20 tau, as predicted, over (partially) vegetated surfaces, consistent with pre-launch theoretical analysis and aircraft field experiments. In coastal and semi-arid regions larger errors are caused predominantly by the uncertainty in evaluating the surface reflectance. The excellent fit was achieved despite the ongoing improvements in instrument characterization and calibration. This results show that MODIS-derived aerosol optical depths can be used quantitatively in many applications with cautions for residual clouds, snow/ice, and water contamination.
811 citations
21 Mar 2003
TL;DR: CALIPSO as discussed by the authors is a satellite that uses active lidar together with passive instruments to provide vertical profiles of aerosols and clouds and their properties which will help address these uncertainties.
Abstract: Current uncertainties in the effects of aerosols and clouds on the Earth radiation budget limit our understanding of the climate system and the potential for global climate change. The CALIPSO satellite will use an active lidar together with passive instruments to provide vertical profiles of aerosols and clouds and their properties which will help address these uncertainties. CALIPSO will fly in formation with the EOS Aqua and CloudSat satellites and the other satellites of the Aqua constellation. The acquisition of simultaneous and coincident observations will allow numerous synergies to be realized by combining CALIPSO observations with complementary observations from other platforms. In particu-lar, cloud observations from the CALIPSO lidar and the CloudSat radar will be complementary, together encompassing the variety of clouds found in the atmosphere, from thin cirrus to deep convective clouds. CALIPSO is being developed within the framework of a collaboration between NASA and CNES and is scheduled for launch in 2004.
717 citations
"Lidar measurements of aerosol at Va..." refers background in this paper
...1 CALIPSO satellite The CALIPSO mission[11], launched on 28 April 2006, has been able to provide the scientific community with vertically resolved measurements of both aerosol and cloud optical properties like depolarization ratio, AOD, and ice/water phase since June 2006[12]....
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...The CALIPSO payload includes a high-powered digital camera, an infrared radiometer, and the two-wavelength (532 and 1064 nm) near-nadir, polarization sensitive elastic backscatter lidar CALIOP [11][12][13]....
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01 Jan 2005
TL;DR: In this article, the DIAL Revisited: BELINDA and White-Light Femtosecond Lidar is revisited: BelinDA and Raman Lidars.
Abstract: to Lidar.- Polarization in Lidar.- Lidar and Multiple Scattering.- Lidar and Atmospheric Aerosol Particles.- High Spectral Resolution Lidar.- Visibility and Cloud Lidar.- Differential-Absorption Lidar for Ozone and Industrial Emissions.- Differential-Absorption Lidar for Water Vapor and Temperature Profiling.- Raman Lidar.- Temperature Measurements with Lidar.- Resonance Scattering Lidar.- Doppler Wind Lidar.- Airborne and Spaceborne Lidar.- DIAL Revisited: BELINDA and White-Light Femtosecond Lidar.
681 citations
"Lidar measurements of aerosol at Va..." refers methods in this paper
...The backscatter solution to the above lidar equation based on Fernald’s method can be written as[7][8][9]...
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