scholarly journals Long-term aerosol optical hygroscopicity study at the ACTRIS SIRTA observatory: synergy between ceilometer and in-situ measurements

2019 ◽  
Author(s):  
Andrés Esteban Bedoya-Velásquez ◽  
Gloria Titos ◽  
Juan Antonio Bravo-Aranda ◽  
Martial Haeffelin ◽  
Olivier Favez ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Mass Fraction ◽  
In Situ Measurements ◽  
Hygroscopic Growth ◽  
Ambient Aerosols ◽  
Inorganic Species ◽  
On Line ◽  
Remote Sensing Techniques ◽  
Aerosol Hygroscopicity

Abstract. An experimental setup to study aerosol hygroscopicity is proposed based on the time evolution of attenuated backscatter coefficients from a ceilometer co-located to an instrumented-tower equipped with meteorological sensors at different heights. This setup is used to analyse a 4.5-year database at the ACTRIS SIRTA observatory in Palaiseau (Paris, France, 2.208º E, 48.713º N, 160 m above sea level). A strict criterion has been established to identify hygroscopic growth cases using ancillary information such as on-line chemical composition, resulting in eight hygroscopic growth cases from a total of 120 potential cases. For the eight cases, the hygroscopic growth-related properties such as the attenuated backscatter enhancement factor fβ (RH) and the hygroscopic growth coefficient γ are evaluated. This study evidence that the hygroscopicity parameter γ increases as the contribution of organic aerosols decreases. In this sense, organic mass fraction is anti-correlated with γ while it shows a positive correlation with the inorganic mass fraction. Among inorganic species, the higher correlation was found for NO3−. This is the first time that hygroscopic enhancement factors retrieved directly for ambient aerosols using remote sensing techniques are combined with on-line chemical composition in-situ measurements to evaluate the role of the different aerosol species on aerosol hygroscopicity.

scholarly journals Long-term aerosol optical hygroscopicity study at the ACTRIS SIRTA observatory: synergy between ceilometer and in situ measurements

2019 ◽  
Vol 19 (11) ◽  
pp. 7883-7896 ◽  
Author(s):  
Andrés Esteban Bedoya-Velásquez ◽  
Gloria Titos ◽  
Juan Antonio Bravo-Aranda ◽  
Martial Haeffelin ◽  
Olivier Favez ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Mass Fraction ◽  
In Situ Measurements ◽  
Hygroscopic Growth ◽  
Ambient Aerosols ◽  
Inorganic Species ◽  
Remote Sensing Techniques ◽  
First Time ◽  
Aerosol Hygroscopicity

Abstract. An experimental setup to study aerosol hygroscopicity is proposed based on the temporal evolution of attenuated backscatter coefficients from a ceilometer colocated with an instrumented tower equipped with meteorological sensors at different heights. This setup is used to analyze a 4.5-year database at the ACTRIS SIRTA observatory in Palaiseau (Paris, France, 2.208∘ E, 48.713∘ N; 160 m above sea level). A strict criterion-based procedure has been established to identify hygroscopic growth cases using ancillary information, such as online chemical composition, resulting in 8 hygroscopic growth cases from a total of 107 potential cases. For these eight cases, hygroscopic growth-related properties, such as the attenuated backscatter enhancement factor fβ (RH) and the hygroscopic growth coefficient γ, are evaluated. This study shows that the hygroscopicity parameter γ is negatively correlated with the aerosol organic mass fraction but shows a positive correlation with the aerosol inorganic mass fraction. Among inorganic species, nitrate exhibited the highest correlation. This is the first time that hygroscopic enhancement factors are directly retrieved under ambient aerosols using remote-sensing techniques, which are combined with online chemical composition in situ measurements to evaluate the role of the different aerosol species in aerosol hygroscopicity.

scholarly journals Measurement report: The effect of aerosol chemical composition on light scattering due to the hygroscopic swelling effect

2021 ◽  
Author(s):  
Rongmin Ren ◽  
Zhanqing Li ◽  
Peng Yan ◽  
Yuying Wang ◽  
Hao Wu ◽  
...  
Keyword(s):  
Light Scattering ◽  
Chemical Composition ◽  
Mass Fraction ◽  
Mass Concentration ◽  
Negative Impact ◽  
Positive Impact ◽  
Parameterization Scheme ◽  
Ambient Aerosols ◽  
Inorganic Matter ◽  
Aerosol Hygroscopicity

Abstract. Liquid water in aerosol particles has a significant effect on optical properties, especially on light scattering, whose dependence on chemical composition is investigated here using measurements made in southern Beijing in 2019. The effect is measured by the enhancement of aerosol hygroscopic factor, f(RH = 85 %, 525 nm), which is found to be positively and negatively impacted by the proportions of inorganic and organic matters respectively. Black carbon is also negatively correlated. The positive impact is more robust when the inorganic matter mass fraction was smaller than 40 % (correlation coefficient, R = 0.93) which becomes weaker as the inorganic matter mass fraction gets larger (R = 0.48). A similar pattern was also found in the negative impact for organic matter mass fraction. Nitrate played a more significant role in aerosol hygroscopicity than sulfate in Beijing. However, the deliquescence point of ambient aerosols was at about RH = 80 % when the ratio of the sulfate mass concentration to the nitrate mass concentration of the aerosol was high (mostly higher than ~4). Two schemes to parameterize f(RH) were developed in accounting for the deliquescent and non-deliquescent effects. Using only one f(RH) parameterization scheme to fit all f(RH) processes would incur large errors. A piecewise parameterization scheme is proposed, which can better describe deliquescence and reduces uncertainties in simulating aerosol hygroscopicity.

scholarly journals Spatiotemporal changes in aerosol properties by hygroscopic growth and impacts on radiative forcing and heating rates during DISCOVER-AQ 2011

2021 ◽  
Vol 21 (15) ◽  
pp. 12021-12048
Author(s):  
Daniel Pérez-Ramírez ◽  
David N. Whiteman ◽  
Igor Veselovskii ◽  
Richard Ferrare ◽  
Gloria Titos ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Water Soluble ◽  
Hygroscopic Growth ◽  
Radiative Effects ◽  
Heating Rates ◽  
Airborne Measurements ◽  
Lidar Measurements ◽  
Cooling Effects ◽  
Aerosol Hygroscopicity

Abstract. This work focuses on the characterization of vertically resolved aerosol hygroscopicity properties and their direct radiative effects through a unique combination of ground-based and airborne remote sensing measurements during the Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) 2011 field campaign in the Baltimore–Washington DC metropolitan area. To that end, we combined aerosol measurements from a multiwavelength Raman lidar located at NASA Goddard Space Flight Center and the airborne NASA Langley High Spectral Resolution Lidar-1 (HSRL-1) lidar system. In situ measurements aboard the P-3B airplane and ground-based Aerosol Robotic Network – Distributed Regional Aerosol Gridded Observational Network (AERONET-DRAGON) served to validate and complement quantifications of aerosol hygroscopicity from lidar measurements and also to extend the study both temporally and spatially. The focus here is on 22 and 29 July 2011, which were very humid days and characterized by a stable atmosphere and increasing relative humidity with height in the planetary boundary layer (PBL). Combined lidar and radiosonde (temperature and water vapor mixing ratio) measurements allowed the retrieval of the Hänel hygroscopic growth factor which agreed with that obtained from airborne in situ measurements and also explained the significant increase of extinction and backscattering with height. Airborne measurements also confirmed aerosol hygroscopicity throughout the entire day in the PBL and identified sulfates and water-soluble organic carbon as the main species of aerosol particles. The combined Raman and HSRL-1 measurements permitted the inversion for aerosol microphysical properties revealing an increase of particle radius with altitude consistent with hygroscopic growth. Aerosol hygroscopicity pattern served as a possible explanation of aerosol optical depth increases during the day, particularly for fine-mode particles. Lidar measurements were used as input to the libRadtran radiative transfer code to obtain vertically resolved aerosol radiative effects and heating rates under dry and humid conditions, and the results reveal that aerosol hygroscopicity is responsible for larger cooling effects in the shortwave range (7–10 W m−2 depending on aerosol load) near the ground, while heating rates produced a warming of 0.12 K d−1 near the top of PBL where aerosol hygroscopic growth was highest.

scholarly journals Spatiotemporal changes in aerosol properties by hygroscopic growth and impacts on radiative forcing and heating rates during DISCOVER-AQ 2011

2021 ◽  
Author(s):  
Daniel Pérez-Ramírez ◽  
David N. Whiteman ◽  
Igor Veselovskii ◽  
Richard Ferrare ◽  
Gloria Titos ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Water Soluble ◽  
Hygroscopic Growth ◽  
Radiative Effects ◽  
Heating Rates ◽  
Airborne Measurements ◽  
Lidar Measurements ◽  
Cooling Effects ◽  
Aerosol Hygroscopicity

Abstract. This work focuses on the characterization of vertically-resolved aerosol hygroscopicity properties and their direct radiative effects through a unique combination of ground-based and airborne remote sensing measurements during the DISCOVER-AQ 2011 field campaign in the Washington D.C. – Baltimore metropolitan area. To that end, we combined measurements from a multiwavelength Raman lidar located at NASA Goddard Space Flight Center and the airborne NASA Langley HSRL-1 lidar system. In-situ measurements on board the P-3B airplane and ground-based AERONET-DRAGON served to validate and complement quantifications of aerosol hygroscopicity from lidar measurements and also to extend the study both temporally and spatially. The focus here is on the 22nd and 29th of July, 2011 which were very humid days and characterized by a stable atmosphere and increasing relative humidity with height in the planetary boundary layer (PBL). Combined lidar and radiosonde measurements allowed the retrieval of the Hänel hygroscopic growth factor which agreed with that obtained from airborne in-situ measurements, and also explained the significant increase of extinction and backscattering with height. Airborne measurements also confirmed aerosol hygroscopicity throughout the entire day in the PBL and identified sulfates and water soluble organic carbon as the main species of aerosol particles. The combined Raman and HSRL-1 measurements permitted the inversion for aerosol microphysical properties revealing an increase of particle radius with altitude consistent with hygroscopic growth. Aerosol hygroscopicity was identified as the main reason to explain aerosol optical depth increases during the day, particularly for fine mode particles. Lidar measurements were used as input to the libRadtram radiative transfer code to obtain vertically-resolved aerosol radiative effects and heating rates under dry and humid conditions, and the results reveal that aerosol hygroscopicity is responsible for larger cooling effects in the shortwave range (7–10 W/m2 depending on aerosol load) near the ground, while heating rates produced a warming of 0.12 K/day near the top of PBL where aerosol hygroscopic growth was highest.

scholarly journals The chemical connection between 67P/C-G and IRAS 16293-2422

2017 ◽  
Vol 13 (S332) ◽  
pp. 196-201
Author(s):  
Maria Nikolayevna Drozdovskaya ◽  
Ewine F. van Dishoeck ◽  
Martin Rubin ◽  
Jes Kristian Jørgensen ◽  
Kathrin Altwegg
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
Chemical Evolution ◽  
Protoplanetary Disks ◽  
In Situ Measurements ◽  
Isotopic Ratios ◽  
Data Sets ◽  
Low Mass ◽  
Comet 67P

AbstractThe chemical evolution of a star- and planet-forming system begins in the prestellar phase and proceeds across the subsequent evolutionary phases. The chemical trail from cores to protoplanetary disks to planetary embryos can be studied by comparing distant young protostars and comets in our Solar System. One particularly chemically rich system that is thought to be analogous to our own is the low-mass IRAS 16293-2422. ALMA-PILS observations have made the study of chemistry on the disk scales (<100 AU) of this system possible. Under the assumption that comets are pristine tracers of the outer parts of the innate protosolar disk, it is possible to compare the composition of our infant Solar System to that of IRAS 16293-2422. The Rosetta mission has yielded a wealth of unique in situ measurements on comet 67P/C-G, making it the best probe to date. Herein, the initial comparisons in terms of the chemical composition and isotopic ratios are summarized. Much work is still to be carried out in the future as the analysis of both of these data sets is still ongoing.

scholarly journals In-situ measurements of the ice flow motion at Eqip Sermia Glacier using a remotely controlled UAV

2019 ◽  
Author(s):  
Guillaume Jouvet ◽  
Eef van Dongen ◽  
Martin P. Lüthi ◽  
Andreas Vieli
Keyword(s):  
Remote Sensing ◽  
Template Matching ◽  
In Situ Measurements ◽  
In Situ Monitoring ◽  
High Temporal Resolution ◽  
Ice Flow ◽  
Flow Motion ◽  
Remote Sensing Techniques ◽  
Matching Techniques

Abstract. Measuring the ice flow motion accurately is essential to better understand the time evolution of glaciers and ice sheets, and therefore to better anticipate the future consequence of climate change in terms of sea-level rise. Although there exist a variety of remote sensing methods to fill this task, in-situ measurements are always needed for validation or to capture high temporal resolution movements. Yet glaciers are in general hostile environments where the installation of instruments might be tedious and risky when not impossible. Here we report the first-ever in-situ measurements of ice flow motion using a remotely controlled Unmanned Aerial Vehicle (UAV). We used a multicopter UAV to land on a highly crevassed area of Eqip Sermia Glacier, West Greenland, to measure the displacement of the glacial surface with the aid of an on-board differential GNSS receiver. Despite the unfortunate loss of the UAV, we measured approximately 70 cm of displacement over 4.36 hours without setting foot onto the glacier – a result validated by applying UAV photogrammetry and template matching techniques. Our study demonstrates that UAVs are promising instruments for in-situ monitoring, and have a great potential for capturing short-term ice flow variations in inaccessible glaciers – a task that remote sensing techniques can hardly achieve.

scholarly journals Remote Sensing

2017 ◽  
Vol 58 ◽  
pp. 10.1-10.21 ◽  
Author(s):  
J. Bühl ◽  
S. Alexander ◽  
S. Crewell ◽  
A. Heymsfield ◽  
H. Kalesse ◽  
...  
Keyword(s):  
Remote Sensing ◽  
In Situ Measurements ◽  
Ice Formation ◽  
Literature Study ◽  
Passive Remote Sensing ◽  
Level Information ◽  
Formation And Evolution ◽  
Remote Sensing Techniques ◽  
Remote Sensing Methods

Abstract State-of-the-art remote sensing techniques applicable to the investigation of ice formation and evolution are described. Ground-based and spaceborne measurements with lidar, radar, and radiometric techniques are discussed together with a global view on past and ongoing remote sensing measurement campaigns concerned with the study of ice formation and evolution. This chapter has the intention of a literature study and should illustrate the major efforts that are currently taken in the field of remote sensing of atmospheric ice. Since other chapters of this monograph mainly focus on aircraft in situ measurements, special emphasis is put on active remote sensing instruments and synergies between aircraft in situ measurements and passive remote sensing methods. The chapter concentrates on homogeneous and heterogeneous ice formation in the troposphere because this is a major topic of this monograph. Furthermore, methods that deliver direct, process-level information about ice formation are elaborated with a special emphasis on active remote sensing methods. Passive remote sensing methods are also dealt with but only in the context of synergy with aircraft in situ measurements.

scholarly journals Aerosol hygroscopicity derived from size-segregated chemical composition and its parameterization in the North China Plain

2014 ◽  
Vol 14 (5) ◽  
pp. 2525-2539 ◽  
Author(s):  
H. J. Liu ◽  
C. S. Zhao ◽  
B. Nekat ◽  
N. Ma ◽  
A. Wiedensohler ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Ultrafine Particles ◽  
Mass Fraction ◽  
North China Plain ◽  
North China ◽  
The North ◽  
The North China Plain ◽  
Mass Fractions ◽  
Particulate Mass ◽  
Aerosol Hygroscopicity

Abstract. Hygroscopic growth of aerosol particles is of significant importance in quantifying the aerosol radiative effect in the atmosphere. In this study, hygroscopic properties of ambient particles are investigated based on particle chemical composition at a suburban site in the North China Plain during the HaChi campaign (Haze in China) in summer 2009. The size-segregated aerosol particulate mass concentration as well as the particle components such as inorganic ions, organic carbon and water-soluble organic carbon (WSOC) are identified from aerosol particle samples collected with a ten-stage impactor. An iterative algorithm is developed to evaluate the hygroscopicity parameter κ from the measured chemical composition of particles. During the HaChi summer campaign, almost half of the mass concentration of particles between 150 nm and 1 μm is contributed by inorganic species. Organic matter (OM) is abundant in ultrafine particles, and 77% of the particulate mass with diameter (Dp) of around 30 nm is composed of OM. A large fraction of coarse particle mass is undetermined and is assumed to be insoluble mineral dust and liquid water. The campaign's average size distribution of κ values shows three distinct modes: a less hygroscopic mode (Dp < 150 nm) with κ slightly above 0.2, a highly hygroscopic mode (150 nm < Dp < 1 μm) with κ greater than 0.3 and a nearly hydrophobic mode (Dp > 1 μm) with κ of about 0.1. The peak of the κ curve appears around 450 nm with a maximum value of 0.35. The derived κ values are consistent with results measured with a high humidity tandem differential mobility analyzer within the size range of 50–250 nm. Inorganics are the predominant species contributing to particle hygroscopicity, especially for particles between 150 nm and 1 μm. For example, NH4NO3, H2SO4, NH4HSO4 and (NH4)2SO4 account for nearly 90% of κ for particles of around 900 nm. For ultrafine particles, WSOC plays a critical role in particle hygroscopicity due to the predominant mass fraction of OM in ultrafine particles. WSOC for particles of around 30 nm contribute 52% of κ. Aerosol hygroscopicity is related to synoptic transport patterns. When southerly wind dominates, particles are more hygroscopic; when northerly wind dominates, particles are less hygroscopic. Aerosol hygroscopicity also has a diurnal variation, which can be explained by the diurnal evolution of planetary boundary layer, photochemical aging processes during daytime and enhanced black carbon emission at night. κ is highly correlated with mass fractions of SO42−, NO3− and NH4+ for all sampled particles as well as with the mass fraction of WSOC for particles of less than 100 nm. A parameterization scheme for κ is developed using mass fractions of SO42−, NO3−, NH4+ and WSOC due to their high correlations with κ, and κ calculated from the parameterization agrees well with κ derived from the particle's chemical composition. Further analysis shows that the parameterization scheme is applicable to other aerosol studies in China.

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