scholarly journals The Observation Path Problems and the Formation Conditions of the Elevated Layer of Black Carbon Aerosol

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 481
Author(s):  
Lianji Jin ◽  
Liang Lin ◽  
Deping Ding ◽  
Delong Zhao ◽  
Bin Zhu ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Black Carbon ◽  
Simulation Analysis ◽  
Mixing Layer ◽  
Horizontal Distribution ◽  
Free Atmosphere ◽  
Observation Area ◽  
Formation Conditions ◽  
Black Carbon Aerosol ◽  
The Vertical Distribution

Studies on the detection of layers with elevated black carbon aerosol (BC) concentrations and the formation conditions of these layers help understand the vertical distribution of BC concentrations, which will provide a basis for the assessment of climate effects and early pollution warnings. By using the Weather Research and Forecasting with Chemistry (WRF-Chem) numerical model, we performed a numerical simulation analysis on the authenticity of strongly elevated BC concentration layers that were detected by an aircraft in the mixing layer over Harbin, China, which is a high-emission area, on a clear sunny afternoon in the early heating period of 2016. We then discuss possible problems and solutions when non-vertical paths are used to detect the vertical distribution of BC concentrations. Finally, we discuss the favorable conditions for the formation of elevated BC concentration layers by a weak vertical flow based on the simulation. The modeling results show that the horizontal variability of BC concentration in the mixing layer in the observation area in Harbin was sufficiently large during the measurement. This produced a false elevated layer, as detected by the aircraft during one round of spiral flight in the mixing layer. The root mean square of the horizontal distribution of BC concentration did not change with height in the mixing layer during the daytime, but it decreased with the thickness of the mixing layer and was higher in the mixing layer than in the free atmosphere. Therefore, the thinner the mixing layer, in which the vertical distribution of the BC concentration is detected in an inclined path, the stronger interference of the horizontal variability on the detected results. In the daytime, due to strong turbulence in the mixing layer, weak vertical uplift is not favorable for the occurrence of elevated BC concentration layers in the mixing layer. In the nighttime, if weak vertical uplift is well-matched with the BC concentration or its vertical gradient, elevated BC concentration layers can be formed in the atmosphere. Compared with upper layers far from the ground, nighttime elevated layers are easier to form in lower layers near the ground because high BC concentrations or large vertical gradients are more likely to occur in the lower layers. Both cases facilitate the occurrence of large vertical upward transport rates of BC.

scholarly journals The Observation Path Problems and the Formation Conditions of the Elevated Layer of Black Carbon Aerosol

2020 ◽  
Author(s):  
Lianji Jin ◽  
Liang Lin ◽  
Deping Ding ◽  
Delong Zhao ◽  
Bin Zhu ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Black Carbon ◽  
Simulation Analysis ◽  
Mixing Layer ◽  
Horizontal Distribution ◽  
Free Atmosphere ◽  
Observation Area ◽  
Formation Conditions ◽  
Black Carbon Aerosol ◽  
The Vertical Distribution

Studies on the detection of layers with elevated black carbon aerosol (BC) concentrations and the formation conditions of these layers help understand the vertical distribution of BC concentrations, which will provide a basis for the assessment of climate effects and early BC pollution warnings. By using the Weather Research and Forecasting with Chemistry (WRF-Chem) numerical model, we performed a numerical simulation analysis on the authenticity of strong elevated BC concentration layers that were detected by an aircraft in the mixing layer over Harbin, China, which is a high-emission area, on a clear sunny afternoon in the early heating period of 2016. We then discuss possible problems and solutions when non-vertical paths are used to detect the vertical distribution of BC concentrations. Finally, we discuss the favorable conditions for the formation of elevated BC concentration layers by weak vertical flow. The results show that the horizontal variability of BC concentration in the mixing layer in the observation area in Harbin was sufficiently large during the measurement. This produced a false elevated layer, as detected by the aircraft during one round of spiral flight in the mixing layer. The root mean square of the horizontal distribution of BC concentration did not change with height in the mixing layer during the daytime, but it decreased with the thickness of the mixing layer and was higher in the mixing layer than in the free atmosphere. Therefore, the thinner the mixing layer, in which the vertical distribution of the BC concentration is detected in an inclined path, the stronger interference of the horizontal variability on the detected results. When a spiral flight detection path is used, the aircraft should fly at least two rounds in the mixing layer. In the daytime, due to strong turbulence in the mixing layer, weak vertical uplift is not favorable for the occurrence of elevated BC concentration layers in the mixing layer. In the nighttime, if weak vertical uplift is well matched with the BC concentration or its vertical gradient, elevated BC concentration layers can be formed in the atmosphere. Compared with upper layers far from the ground, nighttime elevated layers are easier to form in lower layers near the ground because high BC concentrations or large vertical gradients are more likely to occur in the lower layers. Both cases facilitate the occurrence of large vertical upward transport rates of BC.

scholarly journals The vertical distribution of biomass burning pollution over tropical South America from aircraft in situ measurements during SAMBBA

2019 ◽  
Vol 19 (9) ◽  
pp. 5771-5790 ◽  
Author(s):  
Eoghan Darbyshire ◽  
William T. Morgan ◽  
James D. Allan ◽  
Dantong Liu ◽  
Michael J. Flynn ◽  
...  
Keyword(s):  
Air Quality ◽  
South America ◽  
Vertical Distribution ◽  
Biomass Burning ◽  
Mixing Layer ◽  
Free Troposphere ◽  
The West ◽  
The Vertical Distribution ◽  
Tropical South America

Abstract. We examine processes driving the vertical distribution of biomass burning pollution following an integrated analysis of over 200 pollutant and meteorological profiles measured in situ during the South AMerican Biomass Burning Analysis (SAMBBA) field experiment. This study will aid future work examining the impact of biomass burning on weather, climate and air quality. During the dry season there were significant contrasts in the composition and vertical distribution of haze between western and eastern regions of tropical South America. Owing to an active or residual convective mixing layer, the aerosol abundance was similar from the surface to ∼1.5 km in the west and ∼3 km in the east. Black carbon mass loadings were double as much in the east (1.7 µg m−3) than the west (0.85 µg m−3), but aerosol scattering coefficients at 550 nm were similar (∼120 Mm−1), as too were CO near-surface concentrations (310–340 ppb). We attribute these contrasts to the more flaming combustion of Cerrado fires in the east and more smouldering combustion of deforestation and pasture fires in the west. Horizontal wind shear was important in inhibiting mixed layer growth and plume rise, in addition to advecting pollutants from the Cerrado regions into the remote tropical forest of central Amazonia. Thin layers above the mixing layer indicate the roles of both plume injection and shallow moist convection in delivering pollution to the lower free troposphere. However, detrainment of large smoke plumes into the upper free troposphere was very infrequently observed. Our results reiterate that thermodynamics control the pollutant vertical distribution and thus point to the need for correct model representation so that the spatial distribution and vertical structure of biomass burning smoke is captured. We observed an increase of aerosol abundance relative to CO with altitude both in the background haze and plume enhancement ratios. It is unlikely associated with thermodynamic partitioning, aerosol deposition or local non-fire sources. We speculate it may be linked to long-range transport from West Africa or fire combustion efficiency coupled to plume injection height. Further enquiry is required to explain the phenomenon and explore impacts on regional climate and air quality.

scholarly journals On the spatial variability of the regional aerosol distribution as determined from ceilometers

2020 ◽  
Author(s):  
Matthias Wiegner ◽  
Alexander Geiß ◽  
Ina Mattis ◽  
Fred Meier ◽  
Thomas Ruhtz
Keyword(s):  
Vertical Distribution ◽  
Mixing Layer ◽  
Data Set ◽  
Integrated Backscatter ◽  
Aerosol Distribution ◽  
Mixing Layer Height ◽  
Aerosol Sources ◽  
The Mean ◽  
Two Parameters ◽  
The Vertical Distribution

Abstract. Measurements of the vertical distribution of aerosol particles are typically only available at selected sites leaving the question of their representativeness for urban and regional scales unanswered. As a contribution to solve this problem we have investigated ceilometer signals from two testbeds in Munich and Berlin, Germany. For each testbed measurements of 24 months from 6 ceilometers were available. This constitutes a unique data set, in particular as the same type of instruments are deployed and the same data evaluation schemes applied. Two parameters are discussed: the mixing layer height (MLH) as an indicator for the vertical distribution and the integrated backscatter as a proxy for the amount of aerosols in the mixing layer. The MLH was determined by the COBOLT algorithm, the integrated backscatter from the Klett (backward and forward) inversion scheme. It was found that the mean difference of the MLH at two sites within a testbed typically only varies by less than 50 m, slightly increasing with the distance of the corresponding sites. Almost 60 % of all intercomparisons agree within ±100 m. MLHs are typically correlated with R > 0.9 in particular for the Berlin-testbed. With respect to the integrated backscatter the correlation is in the range of 0.7 < R < 0.9. This is expected from the diversity of local aerosol sources within a given testbed. We conclude from our data that the MLH determined from a single ceilometer is applicable for a whole metropolitan area. However, the integrated backscatter of particles within the mixing layer exhibits a variability of 15–25 % suggesting that one ceilometer is not representative, especially if atmospheric processes shall be investigated.

scholarly journals The Vertical Distribution of Marine Macroplankton. II. The Pelagic Young of Teleostean Fishes in the Day-time in the Plymouth Area, with a Note on the Eggs of certain Species

1926 ◽  
Vol 14 (1) ◽  
pp. 101-159 ◽  
Author(s):  
F. S. Russell
Keyword(s):  
Vertical Distribution ◽  
Horizontal Distribution ◽  
Seasonal Distribution ◽  
Teleostean Fish ◽  
Young Fish ◽  
Surface Layers ◽  
Larval Stages ◽  
Different Depths ◽  
The Vertical Distribution

1. Horizontal hauls were made with a “stramin” ring-trawl and a silk net at different depths in 1924 and 1925 to determine the vertical distribution of the pelagic post-larval stages of Teleostean fish in daylight. The depths at which the nets fished on every occasion were obtained by means of a graphic depth-recorder.2. It was indicated that there are specific differences in the behaviour of the post-larvae of various fishes as to their vertical distribution in daylight, some preferring the surface layers, others apparently indifferently distributed from surface to bottom, and others preferring the deeper layers and avoiding the surface; of these last it was found that somespecies became abundant at deeper levels than others. A tentative list of distribution types is given on page 107. 3. Eesults emphasise the necessity when examining the horizontal distribution of young fish of sampling all layers : oblique hauls are to be desired fishing at as many levels as possible. 4. Mention is made of seasonal distribution : the year 1924 appeared to differ from 1925 in that certain post-larvae which were prevalent in the plankton well into June or July in the former year were cut short a month earlier in 1925.The post-larvae of Molva molva and of Lophius piscatorius were unusually abundant in 1924 ; post-larval Gobies (Gobiidce) and Wrasses (Labridce) were extremely scarce in 1925 during the months April to beginning of August.

scholarly journals Horizontal distribution affects the vertical distribution of native and invasive container‐inhabiting Aedes mosquitoes within an urban landscape

2020 ◽  
Vol 45 (1) ◽  
pp. 16-24
Author(s):  
Marcelo Schwarz ◽  
Brian D. Byrd ◽  
Bahjat F. Marayati ◽  
Peter W. Blum ◽  
Michael B. Wells ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Urban Landscape ◽  
Horizontal Distribution ◽  
Aedes Mosquitoes ◽  
The Vertical Distribution

Heavy Metal Distribution and Sources in Pineapple-Growing Agricultural Soil in Hainan Province, China

2014 ◽  
Vol 955-959 ◽  
pp. 1003-1008
Author(s):  
Zhen Zhen Ma ◽  
Yu Guo ◽  
Zheng Yu Bao ◽  
Guo Ai Wu ◽  
Yang Rong Fu
Keyword(s):  
Heavy Metal ◽  
Vertical Distribution ◽  
Agricultural Soil ◽  
Principal Component ◽  
Horizontal Distribution ◽  
Parent Material ◽  
Hainan Province ◽  
Soil Parent Material ◽  
The Vertical Distribution

An investigation on heavy metal content in agricultural soil growing pineapples was carried out in Hainan Province. The horizontal and vertical distribution of heavy metal in different areas was studied. The sources of heavy metal were conducted using principal component analysis. Generally the study areas were less affected by human activity factors and the overall environmental quality was quite better. The uneven horizontal distribution of heavy metal was controlled mainly by the soil parent material and the vertical distribution of heavy metal was limited by both the role of human activities and the natural effect combined.

scholarly journals The Vertical Distribution of Marine Macroplankton. VIII. Further Observations on the Diurnal Behaviour of the Pelagic Young of Teleostean Fishes in the Plymouth Area

1928 ◽  
Vol 15 (3) ◽  
pp. 829-850 ◽  
Author(s):  
F. S. Russell
Keyword(s):  
Vertical Distribution ◽  
Horizontal Distribution ◽  
Young Fish ◽  
Larval Stages ◽  
Cyanea Capillata ◽  
The Vertical Distribution ◽  
Diurnal Behaviour

SUMMARYResults are given of a further series of collections made with the stramin ring-trawl to determine the diurnal behaviour of post-larval stages of Teleostean fishes in the Plymouth area.The catches were very satisfactory and showed that in no case, except for Clupeids and Gobies, was there any really marked movement of young fish towards the surface. This confirms previous observations.It has been shown on this and previous occasions that Clupeids are many times more abundant in the catches at night than in the daytime, and any study of their seasonal or horizontal distribution would probably.have to be carried out at night.For the remaining species, except perhaps Gobies and Callionymus, oblique hauls taken either at day or at night should give a fair picture of seasonal or horizontal distribution. More observations are, however, required.The association of the whiting young with the medusa, Cyanea capillata, is discussed.

scholarly journals The vertical distribution of biomass burning pollution over tropical South America from aircraft in situ measurements during SAMBBA

2018 ◽  
Author(s):  
Eoghan Darbyshire ◽  
William T. Morgan ◽  
James D. Allan ◽  
Dantong Liu ◽  
Michael J. Flynn ◽  
...  
Keyword(s):  
South America ◽  
Vertical Distribution ◽  
Biomass Burning ◽  
Mixing Layer ◽  
Thin Layers ◽  
Horizontal Wind ◽  
Free Troposphere ◽  
The West ◽  
The Vertical Distribution ◽  
Tropical South America

Abstract. To reduce the uncertainties in processes driving the vertical distribution of biomass burning pollutants, and thus impacts on regional weather and climate, we present an integrated analysis of vertical profiles of pollutants and meteorological parameters measured on flights during the 2012 South American Biomass Burning Analysis (SAMBBA) field experiment. During the dry season there were significant contrasts in the composition and vertical distribution of haze between western and eastern regions of tropical South America. Owing to an active or residual convective mixing layer, the aerosol burden was similar from the surface to ~ 1.5 km in the west and ~ 3 km in the east. Black carbon mass loadings were double in the east (1.7 µg cm−3) than west (0.85 µg cm−3) but aerosol scattering coefficients at 550 nm were similar (~ 120 Mm−1), as too were CO surface concentrations (310–340 ppb). We attribute these contrasts to the more flaming combustion of Cerrado fires in the east and more smouldering combustion of deforestation and pasture fires in the west. Horizontal wind shear was important in inhibiting mixed layer growth and plume rise, in addition to advecting pollutants from the Cerrado regions into the remote tropical forest of central Amazonia. Optically thin layers above the mixing layer indicates roles for both plume injection and shallow moist convection in delivering pollution to the lower free troposphere. However, detrainment of large smoke plumes into the upper free troposphere was very infrequently observed. Our results reiterate that thermodynamics control the pollutant vertical distribution and thus point to the need for correct model representation so the spatial distribution and vertical structure of biomass burning smoke is captured. Our observations of relatively large concentrations of aerosol aloft and of CO near surface suggest that there is a greater contribution of pollutants from more complete combustion with altitude. Release of appropriate emissions from the initial more flaming and later residual smouldering phases of a fire at appropriate altitudes may be especially important to ensure models can accurately predict aerosol-radiation, aerosol-cloud and air quality impacts.

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