Airborne measurements of the spatial and spectral distributions of aerosol particles over Hebei area, northern China

Abstract. As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia - Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN) relative to CO (ERCN/CO) fell in the range 14-32 cm-3 ppb-1 in most of the investigated smoke plumes. Particle number emission ratios have to our knowledge not been previously measured in tropical deforestation fires, but our results are in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependent on the fire conditions (combustion efficiency). Variability in ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2), which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, reflecting the fact that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF) for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC) fraction of emissions that are not sampled by the aircraft, which increased the EF by a factor of 1.5-2.1. Vertical transport of smoke from the boundary layer (BL) to the cloud detrainment layer (CDL) and the free troposphere (FT) was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non-precipitating clouds. The detrained aerosol particles released in the CDL and FT were larger than in the unprocessed smoke, mostly due to coagulation and secondary growth, and therefore more efficient at scattering radiation and nucleating cloud droplets. This process may have significant atmospheric implications on a regional and larger scale.

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MADE-IN: a new aerosol microphysics submodel for global simulation of potential atmospheric ice nuclei

Geoscientific Model Development Discussions ◽

10.5194/gmdd-3-2221-2010 ◽

2010 ◽

Vol 3 (4) ◽

pp. 2221-2290 ◽

Cited By ~ 1

Author(s):

V. Aquila ◽

J. Hendricks ◽

A. Lauer ◽

N. Riemer ◽

H. Vogel ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Aerosol Particles ◽

Ice Crystals ◽

Dust Particles ◽

Airborne Measurements ◽

Cloud Processing ◽

Ice Nuclei ◽

Hygroscopic Properties ◽

Mixing States ◽

Made In

Abstract. Black carbon (BC) and mineral dust are among the dominant atmospheric ice nuclei, i.e. aerosol particles that can initiate heterogeneous nucleation of ice crystals. When released, most BC and dust particles are externally mixed with other aerosol compounds. Through coagulation with particles containing soluble material and condensation of gases, externally mixed particles may obtain a coating and be transferred into an internal mixture. The mixing state of BC and dust aerosol particles influences their radiative and hygroscopic properties, as well as their ability of building ice crystals. We introduce the new aerosol microphysics submodel MADE-IN, implemented within the ECHAM/MESSy Atmospheric Chemistry global model (EMAC). MADE-IN is able to track separately mass and number concentrations of BC and dust particles in their different mixing states, as well as particles free of BC and dust. MADE-IN describes these three classes of particles through a superposition of seven log-normally distributed modes, and predicts the evolution of their size distribution and chemical composition. Six out of the seven modes are mutually interacting, allowing for the transfer of mass and number among them. Separate modes for the different mixing states of BC and dust particles in EMAC/MADE-IN allow for explicit simulations of the relevant aging processes, i.e. condensation, coagulation and cloud processing. EMAC/MADE-IN has been evaluated with surface and airborne measurements and performs well both in the planetary boundary layer and in the upper troposphere and lowermost stratosphere. Such a model represents a highly appropriate tool for the study of the concentration and composition of potential atmospheric ice nuclei.

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African volcanic emissions influencing atmospheric aerosol particles over the Amazon rain forest

10.5194/acp-2017-1152 ◽

2017 ◽

Cited By ~ 3

Author(s):

Jorge Saturno ◽

Florian Ditas ◽

Marloes Penning de Vries ◽

Bruna A. Holanda ◽

Mira L. Pöhlker ◽

...

Keyword(s):

Rain Forest ◽

Amazon Basin ◽

Dimethyl Sulfide ◽

Aerosol Particles ◽

Amazon Region ◽

Volcanic Emissions ◽

Airborne Measurements ◽

Amazon Rain Forest ◽

Sulfur Emissions

Abstract. Long-range transport (LRT) plays an important role in the Amazon rain forest by bringing in different primary and secondary aerosol particles from distant sources. The atmospheric oxidation of dimethyl sulfide (DMS), emitted from marine plankton, is considered an important sulfate source over the Amazon rain forest, with a lesser contribution from terrestrial soil and vegetation sulfur emissions. Volcanic sulfur emissions from Africa could be a source of particulate sulfate to the Amazonian atmosphere upon transatlantic transport but no observations have been published. By using satellite observations, together with ground‑based and airborne aerosol particle observations, this paper provides evidence of the influence that volcanic emissions have on the aerosol properties that have been observed in central Amazonia. Under the volcanic influence, sulfate mass concentrations reached up to 3.6 µg m−3 (hourly mean) at ground level, the highest value ever reported in the Amazon region. The hygroscopicity parameter was higher than the characteristic dry-season average, reaching a maximum of 0.36 for accumulation mode aerosol particles. Airborne measurements and satellite data indicated the transport of two different volcanic plumes reaching the Amazon Basin in September 2014 with a sulfate-enhanced layer at an altitude between 4 and 5 km. These observations show that remote volcanic sources can episodically affect the aerosol cycling over the Amazon rain forest and perturb the background conditions. Further studies should address the long-term effect of volcanogenic aerosol particles over the Amazon Basin by running long-term and intensive field measurements in the Amazon region and by monitoring African emissions and their transatlantic transport.

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Airborne measurements of tropospheric ice-nucleating aerosol particles in the Arctic spring

Journal of Geophysical Research Atmospheres ◽

10.1029/2000jd900790 ◽

2001 ◽

Vol 106 (D14) ◽

pp. 15053-15063 ◽

Cited By ~ 97

Author(s):

David C. Rogers ◽

Paul J. DeMott ◽

Sonia M. Kreidenweis

Keyword(s):

Aerosol Particles ◽

The Arctic ◽

Airborne Measurements

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Haze types in Beijing and the influence of agricultural biomass burning

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-8119-2010 ◽

2010 ◽

Vol 10 (17) ◽

pp. 8119-8130 ◽

Cited By ~ 185

Author(s):

W. J. Li ◽

L. Y. Shao ◽

P. R. Buseck

Keyword(s):

Organic Matter ◽

Biomass Burning ◽

Cloud Condensation Nuclei ◽

Aerosol Particles ◽

Fine Fraction ◽

Northern China ◽

Heterogeneous Reactions ◽

Agricultural Biomass ◽

Soot Particles

Abstract. Emissions from agricultural biomass burning (ABB) in northern China have a significant impact on the regional and global climate. The monthly average aerosol optical depth (AOD) at 550 nm in northern China in 2007 had a maximum of 0.7 in June. The AOD measurements are consistent with regional brown hazes that occurred at that time, which was a period of severe aerosol pollution. Aerosol particles were collected in urban Beijing from 12 to 30 June 2007, during a period of high haze, and studied using transmission electron microscopy with energy-dispersive X-ray spectrometry. The dominant particle types collected in the fine fraction (diameter <1 μm) were ammonium sulfate, soot, K2SO4, KNO3, and organic matter, except that the K salts were minor between 21 and 30 June. K-rich particles as tracers of biomass burning, together with wildfire maps, show that intense regional ABB in northern China contributed significantly to the regional haze between 12 and 20 June. We therefore grouped the episodes into type-1 and -2 haze, with the former occurring between 12 and 20 June and the latter between 21 and 30 June. After long-range transport, ABB particles in the type-1 haze exhibited marked changes in morphology, composition, and mixing state. KCl particles were absent, presumably having been converted by heterogeneous reactions to K2SO4 and KNO3. Soot particles were mixed with the other particle types. Abundant organic matter and soluble salts emitted by ABB increased their sizes during transport and resulted in more hygroscopic aerosol particles in downwind areas, becoming additional cloud condensation nuclei. The high AOD (average value 2.2) in Beijing during 12 to 20 June is partly explained by the hygroscopic growth of fine aerosol particles and by the strong absorption of internally mixed soot particles, both coming from regional ABB emissions. Therefore, it is important to consider the origins of the haze, which in turn leads to the different particle types.

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Airborne observations of newly formed boundary layer aerosol particles under cloudy conditions

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-8249-2018 ◽

2018 ◽

Vol 18 (11) ◽

pp. 8249-8264 ◽

Cited By ~ 5

Author(s):

Barbara Altstädter ◽

Andreas Platis ◽

Michael Jähn ◽

Holger Baars ◽

Janine Lückerath ◽

...

Keyword(s):

Boundary Layer ◽

Ultrafine Particles ◽

Aerosol Particles ◽

Inversion Layer ◽

Time Intervals ◽

Flight Duration ◽

Airborne Measurements ◽

Stratocumulus Clouds ◽

Short Time

Abstract. This study describes the appearance of ultrafine boundary layer aerosol particles under classical “non-favourable” conditions at the research site of TROPOS (Leibniz Institute for Tropospheric Research). Airborne measurements of meteorological and aerosol properties of the atmospheric boundary layer (ABL) were repeatedly performed with the unmanned aerial system ALADINA (Application of Light-weight Aircraft for Detecting IN-situ Aerosol) during three seasons between October 2013 and July 2015. More than 100 measurement flights were conducted on 23 different days with a total flight duration of 53 h. In 26 % of the cases, maxima of ultrafine particles were observed close to the inversion layer at altitudes between 400 and 600 m and the particles were rapidly mixed vertically and mainly transported downwards during short time intervals of cloud gaps. This study focuses on two measurement days affected by low-level stratocumulus clouds, but different wind directions (NE, SW) and minimal concentrations (< 4.6 µg m−3) of SO2, as a common indicator for precursor gases at ground. Taken from vertical profiles, the onset of clouds led to a non-linearity of humidity that resulted in an increased turbulence at the local-scale and caused fast nucleation (e.g. Bigg, 1997; Wehner et al., 2010), but in relation to rapid dilution of surrounding air, seen in sporadic clusters of ground data, so that ultrafine particles disappeared in the verticality. The typical “banana shape” (Heintzenberg et al., 2007) of new particle formation (NPF) and growth was not seen at ground and thus these days might not have been classified as NPF event days by pure surface studies.

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Aircraft Observations of Ice Particle Properties in Stratiform Precipitating Clouds

Advances in Meteorology ◽

10.1155/2014/206352 ◽

2014 ◽

Vol 2014 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

Tuanjie Hou ◽

Hengchi Lei ◽

Zhaoxia Hu ◽

Jun Zhou

Keyword(s):

Particle Size ◽

Northern China ◽

Size Spectrum ◽

Airborne Measurements ◽

Particle Properties ◽

Stratiform Clouds ◽

Convective Cells ◽

Parameter Values ◽

Ice Water ◽

Precipitating Clouds

This study presented airborne measurements of ice particle properties in three stratiform precipitating clouds over northern China. By using horizontal observations at selected altitudes, the distributions of ice water content (IWC), particle habits, and particle size spectrum parameters were investigated. The cloud cases were characterized by high IWC values due to the existence of embedded convective cells. Liquid water contents were rather low with the maxima of less than 0.3 g m−3and the general values of less than 0.1 g m−3. The occurrence of large dendritic crystals as well as rimed capped columns and branched crystals indicated that ice seeding from the above cloud layer (6 km altitude or above) contributed significantly to both high ice crystal number concentrations and IWCs. Horizontal observations at selected levels suggested the general decreasing trend of IWC with decreasing temperature only in part of the cloud layers but not throughout the cold layer of the multilayered stratiform clouds. Both exponential and gamma functions were used to characterize the particle size spectrum parameters. The slope parameter values of exponential distributions were primarily in the range of 103–104 m−1. In comparison, slope values of the gamma distribution fits spanned more and a relationship was found between the dispersion and slope values.

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STAAARTE-MED 1998 summer airborne measurements over the Aegean Sea 1. Aerosol particles and trace gases

Journal of Geophysical Research Atmospheres ◽

10.1029/2001jd001337 ◽

2002 ◽

Vol 107 (D21) ◽

pp. AAC 1-1-AAC 1-15 ◽

Cited By ~ 32

Author(s):

Paola Formenti ◽

Thomas Reiner ◽

Detlev Sprung ◽

Meinrat O. Andreae ◽

Manfred Wendisch ◽

...

Keyword(s):

Aerosol Particles ◽

Trace Gases ◽

Aegean Sea ◽

Airborne Measurements

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Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-2791-2005 ◽

2005 ◽

Vol 5 (3) ◽

pp. 2791-2831 ◽

Cited By ~ 4

Author(s):

P. Guyon ◽

G. Frank ◽

M. Welling ◽

D. Chand ◽

P. Artaxo ◽

...

Keyword(s):

Biomass Burning ◽

Large Scale ◽

Aerosol Particles ◽

Secondary Growth ◽

Combustion Efficiency ◽

Vertical Transport ◽

Airborne Measurements ◽

Sampling Campaign ◽

Wide Range ◽

Emission Ratios

Abstract. As part of the LBA-SMOCC (Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall, and Climate) 2002 campaign, we studied the emission of carbon monoxide (CO), carbon dioxide (CO2), and aerosol particles from Amazonian deforestation fires using an instrumented aircraft. Emission ratios for aerosol number (CN) relative to CO (ERCN/CO) fell in the range 14–32 cm-3 ppb-1 for most of the time, in agreement with values usually found from tropical savanna fires. The number of particles emitted per amount biomass burned was found to be dependant on the fire condition (combustion efficiency). Variability in the ERCN/CO between fires was similar to the variability caused by variations in combustion behavior within each individual fire. This was confirmed by observations of CO-to-CO2 emission ratios (ERCO/CO2), which stretched across the same wide range of values for individual fires as for all the fires observed during the sampling campaign, indicating that flaming and smoldering phases are present simultaneously in deforestation fires. Emission factors (EF) for CO and aerosol particles were computed and a correction was applied for the residual smoldering combustion (RSC) fraction of emissions that are not sampled by the aircraft. The correction, previously unpublished for tropical deforestation fires, suggested an EF about one and a half to twice as large for these species. Vertical transport of biomass-burning plumes from the boundary layer (BL) to the cloud detrainment layer (CDL) and the free troposphere (FT) was found to be a very common phenomenon. We observed a 20% loss in particle number as a result of this vertical transport and subsequent cloud processing, attributable to in-cloud coagulation. This small loss fraction suggests that this mode of transport is very efficient in terms of particle numbers and occurs mostly via non-precipitating clouds. The detrained aerosol particles released in the CDL and FT were larger due to coagulation and secondary growth, and therefore more efficient at scattering radiation and nucleating cloud droplets than the fresh particles. This process may have significant atmospheric implications on a regional and larger scale.

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Overview: On the transport and transformation of pollutants in the outflow of major population centres – observational data from the EMeRGe European intensive operational period in summer 2017

10.5194/acp-2021-500 ◽

2021 ◽

Author(s):

M. Dolores Andrés Hernández ◽

Andreas Hilboll ◽

Helmut Ziereis ◽

Eric Förster ◽

Ovid O. Krüger ◽

...

Keyword(s):

Observational Data ◽

Long Range ◽

Atmospheric Chemistry ◽

Field Experiments ◽

Spatial Scales ◽

Aerosol Particles ◽

Mitigation Strategies ◽

Transport And Transformation ◽

Airborne Measurements ◽

Fire Emissions

Abstract. EMeRGe (Effect of Megacities on the transport and transformation of pollutants on the Regional to Global scales) is an international project focusing on atmospheric chemistry, dynamics and transport of local and regional pollution originating in megacities and other major population centres (MPCs). Airborne measurements, taking advantage of the long range capabilities of the HALO research platform (High Altitude and Long range research aircraft, www.halo-spp.de), are a central part of the research project. In order to provide an adequate set of measurements at different spatial scales, two field experiments were positioned in time and space to contrast situations when the photochemical transformation of plumes emerging from MPCs is large. These experiments were conducted in summer 2017 over Europe and in the inter-monsoon period over Asia in spring 2018. The intensive observational periods (IOP) involved HALO airborne measurements of ozone and its precursors, volatile organic compounds, aerosol particles and related species as well as coordinated ground-based ancillary observations at different sites. Perfluorocarbon (PFC) tracer releases and model forecasts supported the flight planning and the identification of pollution plumes. This paper describes the experimental deployment of the IOP in Europe, which comprised 7 HALO research flights with aircraft base in Oberpfaffenhofen (Germany) for a total of 53 flight hours. The MPC targets London (Great Britain), Benelux/Ruhr area (Belgium, The Netherlands, Luxembourg and Germany), Paris (France), Rome and Po Valley (Italy), Madrid and Barcelona (Spain) were investigated. An in-flight comparison of HALO with the collaborating UK-airborne platform FAAM took place to assure accuracy and comparability of the instrumentation on-board. Generally, significant enhancement of trace gases and aerosol particles are attributed to emissions originating in MPCs at distances of hundreds of kilometres from the sources. The proximity of different MPCs over Europe favours the mixing of plumes of different origin and level of processing and hampers the unambiguous attribution of the MPC sources. Similarly, urban plumes mix efficiently with natural sources as desert dust and with biomass burning emissions from vegetation and forest fires. This confirms the importance of wildland fire emissions in Europe and indicates an important but discontinuous contribution to the European emission budget that might be of relevance in the design of efficient mitigation strategies. The synergistic use and consistent interpretation of observational data sets of different spatial and temporal resolution (e.g. from ground-based networks, airborne campaigns, and satellite measurements) supported by modelling within EMeRGe, provides a unique insight to test the current understanding of MPC pollution outflows. The present work provides an overview of the most salient results and scientific questions in the European context, these being addressed in more detail within additional dedicated EMeRGe studies. The deployment and results obtained in Asia will be the subject of separate publications.

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