NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

Rogers, Raymond R.; Hair, Johnathan W.; Hostetler, C. A.; Ferrare, R. A.; Obland, M. D.; Cook, Anthony; Harper, David B.; Burton, S. P.; Shinozuka, Y.; McNaughton, C. S.; Clarke, A. D.; Redemann, Jens; Russell, Philip B.; Livingston, J. M.; Kleinman, Lawrence I.

doi:10.5194/acp-9-4811-2009

Cited by 96 publications

(81 citation statements)

References 31 publications

(33 reference statements)

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“…However, the optical depth in the upper troposphere and stratosphere is generally low (AOD < 0.005) in the absence of any large injections of aerosol into the stratosphere (Jäger, 2005). In a relevant example, Rogers et al (2009) found the 532 nm AOD above 6.3 km to be 0.01 during the Megacity Initiative: Local and Global Research Observations (MILAGRO) campaign during 2006 in Mexico. In order to estimate the possible bias introduced by unaccounted aerosol transmittance, a constant scattering ratio of 1.05 and a lidar ratio of 50 sr is assumed in the 30 km to 8 km region and yields a maximum undetected AOD of 0.011 (T 2 aerosol = 0.978).…”

Section: Uncertainty Due To the Estimate Of The Two-way Transmittancementioning

confidence: 99%

Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

et al. 2011

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To better assess the range of conditions under which CALIOP data products are produced, these validation flights were conducted under both daytime and nighttime lighting conditions, in multiple seasons, and over a large range of latitudes and aerosol and cloud conditions. This paper presents a quantitative assessment of the CALIOP 532 nm calibration (through the 532 nm total attenuated backscatter) using internally calibrated airborne HSRL underflight data and is the most extensive study of CALIOP 532 nm calibration. Results show that HSRL and CALIOP 532 nm total attenuated backscatter agree on average within 2.7% ± 2.1% (CALIOP lower) at night and within 2.9% ± 3.9% (CALIOP lower) during the day, demonstrating the accuracy of the CALIOP 532 nm calibration algorithms. Additionally, comparisons with HSRL show consistency of the CALIOP calibration before and after the laser switch in 2009 as well as improvements in the daytime version 3.01 calibration scheme compared with the version 2 calibration scheme. Potential biases and uncertainties in the methodology relevant to validating satellite lidar measurements with an airborne lidar system are Correspondence to: R. R. Rogers (raymond.r.rogers@nasa.gov) discussed and found to be less than 4.5% ± 3.2% for this validation effort with HSRL. Results from this study are also compared with prior assessments of the CALIOP 532 nm attenuated backscatter calibration.

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Section: Uncertainty Due To the Estimate Of The Two-way Transmittancementioning

confidence: 99%

Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

et al. 2011

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“…to the top of the atmosphere. Rogers et al (2009) have shown in multiple cases (10, 12, 15 March 2006) that AOD over Mexico City drops to 0 at around 4-4.5 km m.s.l. It means that the air above 4.5 km m.s.l.…”

Section: Transect Through Mexico Citymentioning

confidence: 99%

Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign

et al. 2010

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Abstract. On 7 March 2006, a mobile, ground-based, vertical pointing, elastic lidar system made a North-South transect through the Mexico City basin. Column averaged, aerosol size distribution (ASD) measurements were made on the ground concurrently with the lidar measurements. The ASD ground measurements allowed calculation of the column averaged mass extinction efficiency (MEE) for the lidar system (1064 nm). The value of column averaged MEE was combined with spatially resolved lidar extinction coefficients to produce total aerosol mass concentration estimates with the resolution of the lidar (1.5 m vertical spatial and 1 s temporal). Airborne ASD measurements from DOE G-1 aircraft made later in the day on 7 March 2006, allowed the evaluation of the assumptions of constant ASD with height and time used for estimating the column averaged MEE.The results showed that the aerosol loading within the basin is about twice what is observed outside of the basin. The total aerosol base concentrations observed in the basin are of the order of 200 µg/m 3 and the base levels outside are of the order of 100 µg/m 3 . The local heavy traffic events can introduce aerosol levels near the ground as high as 900 µg/m 3 .The article presents the methodology for estimating aerosol mass concentration from mobile, ground-based lidar measurements in combination with aerosol size distribution measurements. An uncertainty analysis of the methodology is also presented.

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“…Unlike standard backscatter lidars, the HSRL technique enables an accurate and unambiguous measurement of aerosol extinction. Rogers et al (2009) compared the HSRL aerosol extinction measurements with aerosol extinction derived from simultaneous measurements from the NASA Ames Airborne Sun Photometer (AATS-14) ) and in situ scattering and absorption measurements from the Hawaii Group for Environmental Aerosol Research (HiGEAR) in situ instruments and found bias differences between HSRL and these instruments to be less than 3% (0.001 km −1 ) at 532 nm; root-mean-square (rms) differences at 532 nm were less than 50% (0.015 km −1 ). These differences are well within the typical state-of-the-art systematic error of 15-20% at visible wavelengths (Schmid et al, 2006).…”

Section: Aerosol Optical Properties and Radiative Influencesmentioning

confidence: 99%

“…7 above, the T0 and T1 sites were set up with state-of-the-art aerosol spectrometers and samplers for characterization of chemical and physical properties including the scattering and absorption of aerosols, particularly in the submicrometer fractions that are anticipated to have the longest lifetimes and have the most impact on regional and potentially global climate forcing. Measurements were also conducted using several airborne platforms: the DOE G-1 that obtained precursor gas and aerosol measurements; a NASA King Air equipped with a High Spectral Resolution Lidar (HSRL) to measure profiles of aerosol extinction, backscattering, and depolarization (Hair et al, 2008;Rogers et al, 2009) Key findings related to aerosol optical properties obtained during MILAGRO are presented below. Some of the measurements and results related to this topic have been described also under Sect.…”

Section: Aerosol Optical Properties and Radiative Influencesmentioning

confidence: 99%

An overview of the MILAGRO 2006 Campaign: Mexico City emissions and their transport and transformation

et al. 2010

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Abstract. MILAGRO (Megacity Initiative: Local And Global Research Observations) is an international collaborative project to examine the behavior and the export of atmospheric emissions from a megacity. The Mexico City Metropolitan Area (MCMA) -one of the world's largest megacities and North America's most populous city -was selected as the case study to characterize the sources, concentrations, transport, and transformation processes of the gases and fine particles emitted to the MCMA atmosphere and to evaluate the regional and global impacts of these emissions. The findings of this study are relevant to the evolution and impacts of pollution from many other megacities.The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City duringCorrespondence to: L. T. Molina (ltmolina@mit.edu) March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, and enlisting over 450 scientists from 150 institutions in 30 countries. Three ground supersites were set up to examine the evolution of the primary emitted gases and fine particles. Additional platforms in or near Mexico City included mobile vans containing scientific laboratories and mobile and stationary upward-looking lidars. Seven instrumented research aircraft provided information about the atmosphere over a large region and at various altitudes. Satellite-based instruments peered down into the atmosphere, providing even larger geographical coverage. The overall campaign was complemented by meteorological forecasting and numerical simulations, satellite observations and surface networks. Together, these research observations have provided the most comprehensive characterization of the MCMA's urban and regional atmospheric composition and chemistry that will take years to analyze and evaluate fully.Published by Copernicus Publications on behalf of the European Geosciences Union. L. T. Molina et al.: Mexico City emissions and their transport and transformationIn this paper we review over 120 papers resulting from the MILAGRO/INTEX-B Campaign that have been published or submitted, as well as relevant papers from the earlier MCMA-2003 Campaign, with the aim of providing a road map for the scientific community interested in understanding the emissions from a megacity such as the MCMA and their impacts on air quality and climate. This paper describes the measurements performed during MILAGRO and the results obtained on MCMA's atmospheric meteorology and dynamics, emissions of gases and fine particles, sources and concentrations of volatile organic compounds, urban and regional photochemistry, ambient particulate matter, aerosol radiative properties, urban plume characterization, and health studies. A summary of key findings from the field study is presented.

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NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

Cited by 96 publications

References 31 publications

Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign

An overview of the MILAGRO 2006 Campaign: Mexico City emissions and their transport and transformation

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