scholarly journals Size distribution, mass concentration, chemical and mineralogical composition and derived optical parameters of the boundary layer aerosol at Tinfou, Morocco, during SAMUM 2006

Tellus B ◽  
2009 ◽  
Vol 61 (1) ◽  
pp. 32-50 ◽  
Author(s):  
K. Kandler ◽  
L. SchüTZ ◽  
C. Deutscher ◽  
M. Ebert ◽  
H. Hofmann ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Size Distribution ◽  
Mass Concentration ◽  
Mineralogical Composition ◽  
Optical Parameters ◽  
Chemical And Mineralogical Composition

scholarly journals Rapid mass growth and enhanced light extinction of atmospheric aerosols during the heating season haze episodes in Beijing revealed by aerosol-chemistry-radiation-boundary layer interaction

2020 ◽  
Author(s):  
Zhuohui Lin ◽  
Yonghong Wang ◽  
Feixue Zheng ◽  
Ying Zhou ◽  
Yishuo Guo ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Chemical Composition ◽  
Ammonium Nitrate ◽  
Size Distribution ◽  
Mass Concentration ◽  
Light Extinction ◽  
Aerosol Chemistry ◽  
Mass Growth ◽  
Aerosol Mass ◽  
Radiation Boundary

Abstract. Despite the numerous studies investigating haze formation mechanism in China, it is still puzzling that intensive haze episodes could form within hours directly following relatively clean periods. Haze has been suggested to be initiated by the variation of meteorological parameters and then to be substantially enhanced by aerosol-radiation-boundary layer feedback. However, knowledge on the detailed chemical processes and the driving factors for extensive aerosol mass accumulation during the feedback is still scarce. Here, the dependency of the aerosol number size distribution, mass concentration and chemical composition on the daytime mixing layer height (MLH) in urban Beijing is investigated. The size distribution and chemical composition-resolved dry aerosol light extinction is also explored. The results indicate that the aerosol mass concentration and fraction of nitrate increased dramatically when the MLH decreased from high to low conditions, corresponding to relatively clean and polluted conditions, respectively. Particles having their dry diameters in the size of ~ 400–700 nm, and especially particle-phase ammonium nitrate and liquid water, contributed greatly to visibility degradation during the winter haze periods. The dependency of aerosol composition on the MLH revealed that ammonium nitrate and aerosol water content increased the most during low MLH conditions, which may have further triggered enhanced formation of sulphate and organic aerosol via heterogeneous reactions. As a result, more sulphate, nitrate and water soluble organics were formed, leading to an enhanced water uptake ability and increased light extinction by the aerosols. The results of this study contribute towards a more detailed understanding of the aerosol-chemistry-radiation-boundary layer feedback that is likely to be responsible for explosive aerosol mass growth events in urban Beijing.

scholarly journals Rapid mass growth and enhanced light extinction of atmospheric aerosols during the heating season haze episodes in Beijing revealed by aerosol–chemistry–radiation–boundary layer interaction

2021 ◽  
Vol 21 (16) ◽  
pp. 12173-12187
Author(s):  
Zhuohui Lin ◽  
Yonghong Wang ◽  
Feixue Zheng ◽  
Ying Zhou ◽  
Yishuo Guo ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Chemical Composition ◽  
Ammonium Nitrate ◽  
Size Distribution ◽  
Mass Concentration ◽  
Light Extinction ◽  
Aerosol Chemistry ◽  
Mass Growth ◽  
Aerosol Mass ◽  
Radiation Boundary

Abstract. Despite the numerous studies investigating haze formation mechanism in China, it is still puzzling that intensive haze episodes could form within hours directly following relatively clean periods. Haze has been suggested to be initiated by the variation of meteorological parameters and then to be substantially enhanced by aerosol–radiation–boundary layer feedback. However, knowledge on the detailed chemical processes and the driving factors for extensive aerosol mass accumulation during the feedback is still scarce. Here, the dependency of the aerosol number size distribution, mass concentration and chemical composition on the daytime mixing layer height (MLH) in urban Beijing is investigated. The size distribution and chemical composition-resolved dry aerosol light extinction is also explored. The results indicate that the aerosol mass concentration and fraction of nitrate increased dramatically when the MLH decreased from high to low conditions, corresponding to relatively clean and polluted conditions, respectively. Particles having their dry diameters in the size of ∼400–700 nm, and especially particle-phase ammonium nitrate and liquid water, contributed greatly to visibility degradation during the winter haze periods. The dependency of aerosol composition on the MLH revealed that ammonium nitrate and aerosol water content increased the most during low MLH conditions, which may have further triggered enhanced formation of sulfate and organic aerosol via heterogeneous reactions. As a result, more sulfate, nitrate and water-soluble organics were formed, leading to an enhanced water uptake ability and increased light extinction by the aerosols. The results of this study contribute towards a more detailed understanding of the aerosol–chemistry–radiation–boundary layer feedback that is likely to be responsible for explosive aerosol mass growth events in urban Beijing.

Towards understanding the size distribution, composition and optical properties of freshly emitted dust and its relationship with the parent sediment

2021 ◽  
Author(s):  
Carlos Pérez García-Pando ◽  
Cristina González-Florez ◽  
Adolfo González-Romero ◽  
Agnesh Panta ◽  
Jesús Yus-Díez ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Size Distribution ◽  
Chemical Properties ◽  
Mineralogical Composition ◽  
Particle Analysis ◽  
Optical Parameters ◽  
Atmospheric Forcing ◽  
Mixing State ◽  
Comprehensive Overview

<p>The physical and chemical properties of dust, i.e. its particle size distribution (PSD), mineralogical composition, shape and mixing state determine its climate effects. However, the lack of experimental data and understanding of the emitted dust and its relationship with the parent sediment and atmospheric forcing limit the extension of climate and dust models to account for potentially important regional variations in dust properties. In this context, the FRontiers in dust minerAloGical coMposition and its Effects upoN climate (FRAGMENT) project is dedicated to understand, constrain and calculate the global mineralogical composition of dust along with its effects upon climate. In September 2019, we conducted an intensive dust field campaign as a part of FRAGMENT near M’hamid El Ghizlane in Morocco, at the edge of the Sahara Desert. During the measurement period, dust events occurred frequently (about every 1-2 days) with varying intensity.</p><p> </p><p>In this contribution, we provide a comprehensive overview and analysis of the sediment and airborne samples collected, and of the time-resolved measurements of dust concentration, PSD, optical properties and atmospheric forcing. We use mineralogical analyses of wet-sieved (totally disturbed) and dry-sieved (minimally disturbed) sediment samples at high particle-size resolution to better understand the fragmentation of sediment aggregates during wind erosion. We analyse the temporal variability of the number and volume PSDs along with the associated size-resolved dust emission fluxes using data from three optical particle counters deployed at different heights. We discuss the size-resolved particle composition, morphology, and mixing-state of the suspended dust determined by single particle analysis with electron microscopy coupled with energy dispersive X-ray detection from samples collected on sticky carbon substrates with cascade impactors, flat-plate samplers, and free-wing impactors. Finally, scattering coefficients at 450, 525 and 635 nm and seven different angles (from 0º to 90º) obtained with a polar nephelometer and absorption coefficients at 370, 470, 520, 590, 660, 880 and 950 nm obtained with an aethalometer are used to analyse the variability of extensive and intensive optical parameters, such as scattering and absorption Ångström exponents (SAE and AAE), backscatter fraction (BF) and multi-wavelength single scattering albedo (SSA) for both PM2.5 and PM10 dust fractions in combination with PSD and meteorological measurements.</p>

scholarly journals Mineralogical Composition and Physical–Mechanical Properties of Dasht-E-Taatrang Zar Sand Deposits (Afghanistan)

2020 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Hemayatullah Ahmadi ◽  
Atal Yousufi ◽  
Amir Mohammad Mosazai
Keyword(s):  
Mechanical Properties ◽  
Construction Material ◽  
Mineralogical Composition ◽  
Xrd Analysis ◽  
Sample Collection ◽  
Extensive Field ◽  
Chemical And Mineralogical Composition ◽  
New City ◽  
Two Phases ◽  
Field Works

Sand is a common construction material used for various purposes, e.g., concrete, mortar, render, screed, and asphalt. The usage depends on its fineness, and its fineness is controlled by its mineralogical composition and physical-mechanical properties. This research aims to determine the chemical and mineralogical composition and the physical-mechanical properties of the Dasht-e-Taatrang Zar sand deposits within the Qarabagh and Bagram districts of Kabul and Parwan provinces in Afghanistan. To achieve the objectives of this research, a review of the existing literature has been combined with new extensive field works for macroscopic studies and sample collection, and laboratory analyses. In total, 23 samples during two phases of field works were collected and subjected to lab works for XRF, Schlich, and XRD analysis to determine the chemical and mineralogical composition; moreover, sieve and Atterberg analysis, specific gravity, soundness, and alkali-silica reaction tests were performed for characterization of the physical-mechanical properties of the studied samples. The results of the tests show that the Taatrang Zar sand deposits are considered as a suitable construction material, and due to their simple accessibility, the deposits have high potential as a construction material supplier for the Kabul new city project (Dehsabz) in Kabul and adjacent Parwan and Kapisa provinces.

scholarly journals Combining airborne in situ and ground-based lidar measurements for attribution of aerosol layers

2018 ◽  
Author(s):  
Anna Nikandrova ◽  
Ksenia Tabakova ◽  
Antti Manninen ◽  
Riikka Väänänen ◽  
Tuukka Petäjä ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Size Distribution ◽  
Aerosol Size Distribution ◽  
Long Range Transport ◽  
Back Trajectories ◽  
Clear Sky ◽  
Temporal And Spatial Variability ◽  
Range Transport ◽  
Temporal And Spatial

Abstract. Understanding the distribution of aerosol layers is important for determining long range transport and aerosol radiative forcing. In this study we combine airborne in situ measurements of aerosol with data obtained by a ground-based High Spectral Resolution Lidar (HSRL) and radiosonde profiles to investigate the temporal and vertical variability of aerosol properties in the lower troposphere. The HSRL was deployed in Hyytiälä, Southern Finland, from January to September 2014 as a part of the US DoE ARM (Atmospheric Radiation Measurement) mobile facility during the BAECC (Biogenic Aerosols – Effects on Cloud and Climate) Campaign. Two flight campaigns took place in April and August 2014 with instruments measuring the aerosol size distribution from 10 nm to 10 µm at altitudes up to 3800 m. Two case studies from the flight campaigns, when several aerosol layers were identified, were selected for further investigation: one clear sky case, and one partly cloudy case. During the clear sky case, turbulent mixing ensured low temporal and spatial variability in the measured aerosol size distribution in the boundary layer whereas mixing was not as homogeneous in the boundary layer during the partly cloudy case. The elevated layers exhibited greater temporal and spatial variability in aerosol size distribution, indicating a lack of mixing. New particle formation was observed in the boundary layer during the clear sky case, and nucleation mode particles were also seen in the elevated layers that were not mixing with the boundary layer. Interpreting local measurements of elevated layers in terms of long-range transport can be achieved using back trajectories from Lagrangian models, but care should be taken in selecting appropriate arrival heights, since the modelled and observed layer heights did not always coincide. We conclude that higher confidence in attributing elevated aerosol layers with their air mass origin is attained when back trajectories are combined with lidar and radiosonde profiles.

scholarly journals A global off-line model of size-resolved aerosol microphysics: I. Model development and prediction of aerosol properties

2005 ◽  
Vol 5 (8) ◽  
pp. 2227-2252 ◽  
Author(s):  
D. V. Spracklen ◽  
K. J. Pringle ◽  
K. S. Carslaw ◽  
M. P. Chipperfield ◽  
G. W. Mann
Keyword(s):  
Boundary Layer ◽  
Sulfuric Acid ◽  
Size Distribution ◽  
Marine Boundary Layer ◽  
Transport Model ◽  
Model Development ◽  
Aerosol Size Distribution ◽  
Chemical Transport Model ◽  
Cloud Processing ◽  
Nucleation Mechanisms

Abstract. A GLObal Model of Aerosol Processes (GLOMAP) has been developed as an extension to the TOMCAT 3-D Eulerian off-line chemical transport model. GLOMAP simulates the evolution of the global aerosol size distribution using a sectional two-moment scheme and includes the processes of aerosol nucleation, condensation, growth, coagulation, wet and dry deposition and cloud processing. We describe the results of a global simulation of sulfuric acid and sea spray aerosol. The model captures features of the aerosol size distribution that are well established from observations in the marine boundary layer and free troposphere. Modelled condensation nuclei (CN>3nm) vary between about 250–500 cm-3 in remote marine boundary layer regions and are generally in good agreement with observations. Modelled continental CN concentrations are lower than observed, which may be due to lack of some primary aerosol sources or the neglect of nucleation mechanisms other than binary homogeneous nucleation of sulfuric acid-water particles. Remote marine CN concentrations increase to around 2000–10 000 cm

scholarly journals Chemical and mineralogical composition of clay fraction found in Podillia upland haplic chernozems

2017 ◽  
pp. 278-292
Author(s):  
Igor Papish ◽  
Oleksii Telehuz
Keyword(s):  
Clay Fraction ◽  
Soil Formation ◽  
Mineralogical Composition ◽  
Development Stage ◽  
Potassium Feldspar ◽  
Forest Steppe ◽  
Molar Ratios ◽  
Haplic Chernozems ◽  
Typical Chernozems ◽  
Chemical And Mineralogical Composition

The article presents data on gross chemical and mineralogical composition of clay faction found in typical chernozems occurred within the Podillia Upland. Geographical regularities of formation as regards clayey profile of Chernozems pertaining to the same genetic series are revealed. The relationship between conditions and Chernozem development stage, character of vertical differentiation of basic mineral phases of clayey plasma and its chemical and mineralogical composition are shown. Izoclayey profile of hydromicas is the consequence of their relative accumulation as a result eluviation of colloid-dispersible mica-smectite minerals. The character of clay profile observed in Chernozems is determined by the correlation of intensity of carbonates leaching, lessivage and soils argillisation. Typical Podolian Chernozems are characterised with the like weathering crust of silicate type. The modern Chernozem clayey profile originated mainly during a wetter stage of soil formation. In the ploughable layer a high content of clastic minerals (quartz, potassium feldspar, sodium plagioclase) is observed. Random mixed and stratified mica-smectite minerals with a high content (>50 %) of smectite packets (33–63 %), hydromica (33–52 %), and kaolinite plus chlorite (4–15 %) are present in the profile. The mineralogical composition of soils clay fraction indicates obvious signs of smectite eluviation and relative illite accumulation. Clayey profile of the Bug upstream plateau located within the Podillia Upland is atypical for Chernozems found in the eastern forest-steppe and steppe areas. The distribution character of layered silicates, especially smectite, is even more contrastive. Clayey plasma redistributes differentially through leaching and lessivage processes. Accumulative type of sludge deposits formed in Chernozems of the Dniester plateau located within the Podillia Upland, even profile distribution of basic oxides and molar ratios of SiO2 : Al2O3 and SiO2 : Fe2O3 against the background of decreased downward smectite content indicate weakened eluviation of fine-grained clays towards the Dniester. The prevalence of smectite over hydromicas within the entire profile indicates argillisation of Chernozems. Key words: Chernozem, chemical-mineralogical composition, clayey minerals, hydromica, smectite, kaolinite, leaching, lessivage, argillisation.

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