355-nm high spectral resolution airborne lidar LNG: system description and first results

Bruneau, Didier; Pelon, Jacques; Blouzon, F.; Spatazza, Joseph; Genau, Pascal; Buchholtz, G.; Amarouche, Nadir; Abchiche, Abdelkader; Aouji, Oualid

doi:10.1364/ao.54.008776

Cited by 54 publications

(48 citation statements)

References 19 publications

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“…The ATR-42 will be equipped with advanced instrumentation including the multiwavelength Leandre New Generation (LNG) HSR backscatter lidar (Bruneau et al 2015), the 95 GHz Doppler radar RASTA (RAdar SysTem Airborne, Delanoë et al 2013), the mini-cloud radar BASTA (Delanoë et al 2016), and the mini-lidar ALiAS developed at LSCE (Chazette et al 2007;Chazette 2016). The first three instruments have been developed at LATMOS 1 to characterize clouds, aerosol particles and hydrometeor particle velocities.…”

Section: The Atr-42 Aircraft and Its Instrumentationmentioning

confidence: 99%

“…It operates in a direct detection mode (measurement of the backscattered light intensity), which has the advantage of relying on both particulate and molecular scattering, and allows extended ranges and capabilities. Thanks to its two-wave interferometry system (MachZehnder Interferometer) and its capability of high-spectral-resolution UV analysis, it can determine both optical parameters of aerosol and clouds and measurements of along-lineof-sight wind velocity, based on the Doppler effect on particles (Bruneau and Pelon 2003;Bruneau et al 2015). When scattering particles are moving, the wavelength of the scattered light is shifted by a small amount as a function of speed.…”

Section: The Atr-42 Aircraft and Its Instrumentationmentioning

confidence: 99%

“…the total backscatter divided by the molecular backscatter) measured on the same channel. The accuracy of the LNG system along the line of sight after aircraft motions are removed has been assessed for a case of cirrus clouds by Bruneau et al (2015) based on the apparent aircraft speed derived from LNG ground-echo, and based on results from a recent field campaign (NAWDEX-North Atlantic Waveguide and Downstream Impact Experiment, fall 2016): the accuracy of LNG wind speed measurements in these conditions was expected to be around 1 m s À1 (D. Bruneau, personal communication).…”

Section: The Atr-42 Aircraft and Its Instrumentationmentioning

confidence: 99%

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EUREC4A: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation

et al. 2017

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Trade-wind cumuli constitute the cloud type with the highest frequency of occurrence on Earth, and it has been shown that their sensitivity to changing environmental conditions will critically influence the magnitude and pace of future global warming. Research over the last decade has pointed out the importance of the interplay between clouds, convection and circulation in controling this sensitivity. 123Surv Geophys (2017) 38:1529-1568 https://doi.org/10.1007/s10712-017-9428-0 cumuli at cloud base is very sensitive to changes in environmental conditions, while process models suggest the opposite. To understand and resolve this contradiction, we propose to organize a field campaign aimed at quantifying the physical properties of tradecumuli (e.g., cloud fraction and water content) as a function of the large-scale environment. Beyond a better understanding of clouds-circulation coupling processes, the campaign will provide a reference data set that may be used as a benchmark for advancing the modelling and the satellite remote sensing of clouds and circulation. It will also be an opportunity for complementary investigations such as evaluating model convective parameterizations or studying the role of ocean mesoscale eddies in air-sea interactions and convective organization.

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Section: The Atr-42 Aircraft and Its Instrumentationmentioning

confidence: 99%

Section: The Atr-42 Aircraft and Its Instrumentationmentioning

confidence: 99%

Section: The Atr-42 Aircraft and Its Instrumentationmentioning

confidence: 99%

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EUREC4A: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation

et al. 2017

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“…Details on the CALIOP instrument, data acquisition and science products are given by Winker et al (2007). In this work, we use CALIOP level-2 data version 4.10 ( Kim et al, 2018), which was corrected for aerosol types, as noted in Burton et al (2012). The aerosol types identified in the free troposphere (FT) are typically polluted dust and elevated smoke (see example in Appendix A).…”

Section: Datementioning

confidence: 99%

Evidence of the complexity of aerosol transport in the lower troposphere on the Namibian coast during AEROCLO-sA

et al. 2019

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Abstract. The evolution of the vertical distribution and optical properties of aerosols in the free troposphere, above stratocumulus, is characterized for the first time over the Namibian coast, a region where uncertainties on aerosol–cloud coupling in climate simulations are significant. We show the high variability of atmospheric aerosol composition in the lower and middle troposphere during the Aerosols, Radiation and Clouds in southern Africa (AEROCLO-sA) field campaign (22 August–12 September 2017) around the Henties Bay supersite using a combination of ground-based, airborne and space-borne lidar measurements. Three distinct periods of 4 to 7 d are observed, associated with increasing aerosol loads (aerosol optical thickness at 550 nm ranging from ∼0.2 to ∼0.7), as well as increasing lofted aerosol layer depth and top altitude. Aerosols are observed up to 6 km above mean sea level during the later period. Aerosols transported within the free troposphere are mainly polluted dust (predominantly dust mixed with smoke from fires) for the first two periods (22 August–1 September 2017) and smoke for the last part (3–9 September) of the field campaign. As shown by Lagrangian back-trajectory analyses, the main contribution to the aerosol optical thickness over Henties Bay is shown to be due to biomass burning over Angola. Nevertheless, in early September, the highest aerosol layers (between 5 and 6 km above mean sea level) seem to come from South America (southern Brazil, Argentina and Uruguay) and reach Henties Bay after 3 to 6 d. Aerosols appear to be transported eastward by the midlatitude westerlies and towards southern Africa by the equatorward moving cut-off low originating from within the westerlies. All the observations show a very complex mixture of aerosols over the coastal regions of Namibia that must be taken into account when investigating aerosol radiative effects above stratocumulus clouds in the southeast Atlantic Ocean.

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“…The aircraft was equipped with the LEANDRE Nouvelle Génération (LNG) backscatter lidar (Bruneau et al, 2015). The profiles of atmospheric extinction coefficient at 532 nm were retrieved using a standard lidar inversion method that employs a backscatter-to-extinction ratio of 0.0205 sr −1 (see Schepanski et al, 2013, for a more detailed description of the inversion method).…”

Section: Observationsmentioning

confidence: 99%

Fennec dust forecast intercomparison over the Sahara in June 2011

et al. 2016

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Abstract. In the framework of the Fennec international programme, a field campaign was conducted in June 2011 over the western Sahara. It led to the first observational data set ever obtained that documents the dynamics, thermodynamics and composition of the Saharan atmospheric boundary layer (SABL) under the influence of the heat low. In support to the aircraft operation, four dust forecasts were run daily at low and high resolutions with convection-parameterizing and convection-permitting models, respectively. The unique airborne and ground-based data sets allowed the first ever intercomparison of dust forecasts over the western Sahara. At monthly scale, large aerosol optical depths (AODs) were forecast over the Sahara, a feature observed by satellite retrievals but with different magnitudes. The AOD intensity was correctly predicted by the high-resolution models, while it was underestimated by the low-resolution models. This was partly because of the generation of strong near-surface wind associated with thunderstorm-related density currents that could only be reproduced by models representing convection explicitly. Such models yield emissions mainly in the afternoon that dominate the total emission over the western fringes of the Adrar des Iforas and the Aïr Mountains in the high-resolution forecasts. Over the western Sahara, where the harmattan contributes up to 80 % of dust emission, all the models were successful in forecasting the deep wellmixed SABL. Some of them, however, missed the large nearsurface dust concentration generated by density currents and low-level winds. This feature, observed repeatedly by the airborne lidar, was partly forecast by one high-resolution model only.

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355-nm high spectral resolution airborne lidar LNG: system description and first results

Cited by 54 publications

References 19 publications

EUREC4A: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation

EUREC4A: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation

Evidence of the complexity of aerosol transport in the lower troposphere on the Namibian coast during AEROCLO-sA

Fennec dust forecast intercomparison over the Sahara in June 2011

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