scholarly journals Towards parameterising atmospheric concentrations of ice-nucleating particles active at moderate supercooling

2021 ◽  
Vol 21 (2) ◽  
pp. 657-664
Author(s):  
Claudia Mignani ◽  
Jörg Wieder ◽  
Michael A. Sprenger ◽  
Zamin A. Kanji ◽  
Jan Henneberger ◽  
...  
Keyword(s):  
Aerosol Particle ◽  
Aerosol Particles ◽  
Swiss Alps ◽  
Dust Particles ◽  
Ice Formation ◽  
Coarse Particles ◽  
Substantial Fraction ◽  
Cloud Droplets ◽  
Air Mass ◽  
Atmospheric Concentrations

Abstract. A small fraction of freezing cloud droplets probably initiates much of the precipitation above continents. Only a minute fraction of aerosol particles, so-called ice-nucleating particles (INPs), can trigger initial ice formation at −15 ∘C, at which cloud-top temperatures are frequently associated with snowfall. At a mountaintop site in the Swiss Alps, we found that concentrations of INPs active at −15 ∘C can be parameterised by different functions of coarse (> 2 µm) aerosol particle concentrations, depending on whether an air mass is (a) precipitating, (b) non-precipitating, or (c) carrying a substantial fraction of dust particles while non-precipitating. Consequently, we suggest that a parameterisation at moderate supercooling should consider coarse particles in combination with air mass differentiation.

scholarly journals Towards parametrising atmospheric concentrations of ice nucleating particles active at moderate supercooling

2020 ◽  
Author(s):  
Claudia Mignani ◽  
Jörg Wieder ◽  
Michael A. Sprenger ◽  
Zamin A. Kanji ◽  
Jan Henneberger ◽  
...  
Keyword(s):  
Aerosol Particle ◽  
Aerosol Particles ◽  
Swiss Alps ◽  
Saharan Dust ◽  
Ice Formation ◽  
Coarse Particles ◽  
Cloud Droplets ◽  
Air Mass ◽  
Atmospheric Concentrations ◽  
Cloud Top Temperature

Abstract. A small fraction of freezing cloud droplets probably initiates much of the precipitation above continents. Only a minute fraction of aerosol particles, so-called ice nucleating particles (INPs), can trigger initial ice formation at −15 °C, a cloud-top temperature frequently associated with snowfall. We found at a mountain top site in the Swiss Alps that concentrations of INPs active at −15 °C are different functions of coarse (> 2 μm) aerosol particle concentrations, depending on whether an air mass is precipitating, non-precipitating, or carrying Saharan dust and non-precipitating. Consequently, we suggest that a parameterisation at moderate supercooling should consider coarse particles in combination with air mass differentiation.

scholarly journals Mineral and biological ice-nucleating particles above the South East of the British Isles

2021 ◽  
Author(s):  
Alberto Sanchez-Marroquin ◽  
Jonathan S. West ◽  
Ian Burke ◽  
James B McQuaid ◽  
Benjamin John Murray
Keyword(s):  
Aerosol Particles ◽  
Ice Formation ◽  
British Isles ◽  
The South ◽  
Cloud Droplets ◽  
Homogeneous Freezing

A small fraction of aerosol particles known as Ice-Nucleating Particles (INPs) have the potential to trigger ice formation in cloud droplets at higher temperatures than homogeneous freezing. INPs can strongly...

scholarly journals Laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF): performance, reference spectra and classification of atmospheric samples

2018 ◽  
Vol 11 (4) ◽  
pp. 2325-2343 ◽  
Author(s):  
Xiaoli Shen ◽  
Ramakrishna Ramisetty ◽  
Claudia Mohr ◽  
Wei Huang ◽  
Thomas Leisner ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Aerosol Particle ◽  
Mass Spectrometer ◽  
Size Range ◽  
Aerosol Particles ◽  
Time Of Flight ◽  
Polystyrene Latex ◽  
Dust Particles ◽  
Data Set ◽  
Flight Mass Spectrometer

Abstract. The laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF, AeroMegt GmbH) is able to identify the chemical composition and mixing state of individual aerosol particles, and thus is a tool for elucidating their impacts on human health, visibility, ecosystem, and climate. The overall detection efficiency (ODE) of the instrument we use was determined to range from  ∼  (0.01 ± 0.01) to  ∼  (4.23 ± 2.36) % for polystyrene latex (PSL) in the size range of 200 to 2000 nm,  ∼  (0.44 ± 0.19) to  ∼  (6.57 ± 2.38) % for ammonium nitrate (NH4NO3), and  ∼  (0.14 ± 0.02) to  ∼  (1.46 ± 0.08) % for sodium chloride (NaCl) particles in the size range of 300 to 1000 nm. Reference mass spectra of 32 different particle types relevant for atmospheric aerosol (e.g. pure compounds NH4NO3, K2SO4, NaCl, oxalic acid, pinic acid, and pinonic acid; internal mixtures of e.g. salts, secondary organic aerosol, and metallic core–organic shell particles; more complex particles such as soot and dust particles) were determined. Our results show that internally mixed aerosol particles can result in spectra with new clusters of ions, rather than simply a combination of the spectra from the single components. An exemplary 1-day ambient data set was analysed by both classical fuzzy clustering and a reference-spectra-based classification method. Resulting identified particle types were generally well correlated. We show how a combination of both methods can greatly improve the interpretation of single-particle data in field measurements.

scholarly journals Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign at Värriö field station

2007 ◽  
Vol 7 (14) ◽  
pp. 3683-3700 ◽  
Author(s):  
T. M. Ruuskanen ◽  
M. Kaasik ◽  
P. P. Aalto ◽  
U. Hõrrak ◽  
M. Vana ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Aerosol Particle ◽  
Aerosol Particles ◽  
Particle Formation ◽  
Nucleation Event ◽  
New Particle Formation ◽  
Air Ions ◽  
Field Station ◽  
Air Mass ◽  
Measurement Campaign

Abstract. The LAPBIAT measurement campaign took place in the Värriö SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the measurement campaign, concentrations and fluxes of aerosol particles, air ions and trace gases, paying special attention to an aerosol particle formation event broken by a air mass change from a clean Arctic air mass with new particle formation to polluted one approaching from industrial areas of Kola Peninsula, Russia, lacking new particle formation. Aerosol particle number flux measurements show strong downward fluxes during that time. Concentrations of coarse aerosol particles were high for 1–2 days before the nucleation event (i.e. 28–29 April), very low immediately before and during the observed aerosol particle formation event (30 April) and increased moderately from the moment of sudden break of the event. In general particle deposition measurements based on snow samples show the same changes. Measurements of the mobility distribution of air ions showed elevated concentrations of intermediate air ions during the particle formation event. We estimated the growth rates in the nucleation mode size range. For particles <10 nm, the growth rate increases with size on 30 April. Dispersion modelling made with model SILAM support the conclusion that the nucleation event was interrupted by an outbreak of sulphate-rich air mass in the evening of 30 April that originated from the industry at Kola Peninsula, Russia. The results of this campaign highlight the need for detailed research in atmospheric transport of air constituents for understanding the aerosol dynamics.

scholarly journals New particle-dependent parameterizations of heterogeneous freezing processes: sensitivity studies of convective clouds with an air parcel model

2015 ◽  
Vol 15 (22) ◽  
pp. 12741-12763 ◽  
Author(s):  
K. Diehl ◽  
S. K. Mitra
Keyword(s):  
Aerosol Particle ◽  
Dust Particles ◽  
Ice Formation ◽  
Collision Kernel ◽  
Particle Spectrum ◽  
Particle Type ◽  
Sensitivity Studies ◽  
Immersion Freezing ◽  
Ice Water ◽  
The Impact

Abstract. Based on the outcome of laboratory results, new particle-dependent parameterizations of heterogeneous freezing were derived and used to improve and extend a two-dimensional spectral microphysics scheme. They include (1) a particle-type-dependent parameterization of immersion freezing using the numbers of active sites per mass, (2) a particle-type and size-resolved parameterization of contact freezing, and (3) a particle-type-dependent description of deposition freezing. The modified microphysical scheme was embedded in an adiabatic air parcel model with entrainment. Sensitivity studies were performed to simulate convective situations and to investigate the impact of ice nuclei concentrations and types on ice formation. As a central diagnostic parameter, the ice water fraction (IWF) was selected, which is the relation of the ice water content to the total amount of water in the condensed form. The following parameters were varied: initial aerosol particle number size distributions, types of ice nucleating particles, final temperature, and the fractions of potential ice nucleating particles. Single and coupled freezing processes were investigated. The results show that immersion freezing seems to be the most efficient process. Contact freezing is constrained by the collision kernel between supercooled drops and potential ice nucleating particles. The importance of deposition freezing lies in secondary ice formation; i.e., small ice particles produced by deposition nucleation trigger the freezing of supercooled drops by collisions. Thus, a broader ice particle spectrum is generated than that by immersion and contact freezing. During coupled immersion–contact and contact–deposition freezing no competition was observed, and both processes contribute to cloud ice formation but do not impede each other. As already suggested in the literature, mineral dust particles seem to be the most important ice nucleating particles. Biological particles are probably not involved in significant ice formation. The sensitive parameters affecting cloud properties are temperature, aerosol particle composition and concentration, and particle size distribution.

Regional air quality in Leipzig, Germany: detailed source apportionment of size-resolved aerosol particles and comparison with the year 2000

2016 ◽  
Vol 189 ◽  
pp. 291-315 ◽  
Author(s):  
D. van Pinxteren ◽  
K. W. Fomba ◽  
G. Spindler ◽  
K. Müller ◽  
L. Poulain ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Coal Combustion ◽  
Elemental Carbon ◽  
Aerosol Particles ◽  
Biomass Combustion ◽  
Coarse Particles ◽  
Air Mass ◽  
Accumulation Mode ◽  
Secondary Formation ◽  
Year 2000

A detailed source apportionment of size-resolved aerosol particles in the area of Leipzig, Germany, was performed. Sampling took place at four sites (traffic, traffic/residential, urban background, regional background) in parallel during summer 2013 and the winters 2013/14/15. Twenty-one samples were taken per season with a 5-stage Berner impactor and analysed for particulate mass, inorganic ions, organic and elemental carbon, water-soluble organic carbon, trace metals, and a wide range of organic species. The compositional data were used to estimate source contributions to particulate matter (PM) in quasi-ultrafine (up to 140 nm), accumulation mode, and coarse size ranges using Positive Matrix Factorisation (PMF) receptor modelling. Traffic (exhaust and general traffic emissions), coal combustion, biomass combustion, photochemistry, general secondary formation, cooking, fungal spores, urban dust, fresh sea/road salt, and aged sea salt were all found to contribute to different extents to observed PM concentrations. PMF derived estimates agreed reasonably with estimates from established macrotracer approaches. Quasi-ultrafine PM originated mainly from traffic (20–50%) and photochemistry (30–50%) in summer, while it was dominated by solid fuel (mainly biomass) combustion in winter (50–70%). Tentatively identified cooking aerosol contributed up to 36% on average at the residential site. For accumulation mode particles, two secondary sources typically contributed 40–90% to particle mass. In winter, biomass and coal combustion contributions were up to ca. 25% and 45%, respectively. Main sources of coarse particles were diverse and included nearly all PMF-resolved ones depending on season and air mass origin. For PM10, traffic (typically 20–40% at kerbside sites), secondary formation (30–60%), biomass combustion (10–15% in winter), and coal combustion (30–40% in winter with eastern air mass inflow) were the main quantified sources. At the residential site, contributions from biomass combustion derived up to 60% from local emissions. Coal combustion as a significant source was only present during eastern air mass inflow and showed very similar concentrations at all sites, indicating the importance of trans-boundary air pollution transport in the study area. Overall, nearly half of the PM10 mass was attributed to urban sources by a simple subtractive approach with highest reduction potentials of up to 80% for local (urban) mitigation measures in ultrafine and coarse particles. Local increments of elemental carbon have decreased by about 50% as compared to the year 2000, corroborating results from a former study on the positive effects of a low emission zone, implemented in Leipzig in 2011.

scholarly journals Concentrations and fluxes of aerosol particles during the LAPBIAT measurement campaign in Värriö field station

2007 ◽  
Vol 7 (1) ◽  
pp. 709-751
Author(s):  
T. M. Ruuskanen ◽  
M. Kaasik ◽  
P. P. Aalto ◽  
U. Hõrrak ◽  
M. Vana ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Aerosol Particle ◽  
Particle Deposition ◽  
Aerosol Particles ◽  
Particle Formation ◽  
Nucleation Event ◽  
Air Ions ◽  
Field Station ◽  
Air Mass ◽  
Measurement Campaign

Abstract. The LAPBIAT measurement campaign took place in the SMEAR I measurement station located in Eastern Lapland in the spring of 2003 between 26 April and 11 May. In this paper we describe the measurement campaign, concentrations and fluxes of aerosol particles, air ions and trace gases, paying special attention to an aerosol particle formation event broken by a polluted air mass approaching from industrial areas of Kola Peninsula, Russia. Aerosol particle number flux measurements show strong downward fluxes during that time. Concentrations of coarse aerosol particles were high for 1–2 days before the nucleation event (i.e. 28–29 April), very low immediately before and during the observed aerosol particle formation event (30 April) and increased moderately from the moment of sudden break of the event. In general particle deposition measurements based on snow samples show the same changes. Measurements of the mobility distribution of air ions showed elevated concentrations of intermediate air ions during the particle formation event. We estimated the growth rates in the nucleation mode size range. For particles <10 nm, the growth rate increases with size on 30 April. Dispersion modelling made with model SILAM support the conclusion that the nucleation event was interrupted by an outbreak of sulphate-rich air mass in the evening of 30 April that originated from the industry at Kola Peninsula, Russia. The results of this campaign highlight the need for detailed research in atmospheric transport of air constituents for understanding the aerosol dynamics.

Peculiarities of Registration of Fungi Spores in the Air with the Help of Aerosol Particles Counters

2019 ◽  
pp. 71-79
Author(s):  
A.V. Aleksandrova ◽  
E.A. Antonov ◽  
M.I. Veselaya ◽  
V.I. Kalechits ◽  
I.E. Kovbasyuk ◽  
...  
Keyword(s):  
Aerosol Particle ◽  
Aerosol Particles ◽  
Fungal Spores ◽  
Airborne Particles ◽  
Dust Particles ◽  
Background Concentrations ◽  
Particle Counter ◽  
Suspended State ◽  
Large Size ◽  
Aerosol Particle Size

The applicability of laser aerosol particle counters for the registration of microscopic fungal spores in the airborne state (including in the presence of background concentrations of atmospheric airborne particles) was demonstrated during the experiments, and a technique was developed to transfer large (from one to several tens of microns in diameter) fungal spores to the air-suspended state, and to register them confidently with a resolution ensuring their identification. Despite the relatively large size of spores, their detection by the aerosol particle counter is possible for a period of time sufficient to track the movement of spores over significant (compared to conventional dust particles) distances. At the same time, according to the results of measurements, it is possible to judge not only the presence of spores in the air, their size, quantity and ways of movement, but also to draw some preliminary conclusions about their properties, in particular, about the tendency to glue and form aggregates. fungal spores, aerosol, particle size distribution, aerosol particle counter.

scholarly journals Measurements of Ice Nucleating Particles and Ice Residuals

2017 ◽  
Vol 58 ◽  
pp. 8.1-8.13 ◽  
Author(s):  
Daniel J. Cziczo ◽  
Luis Ladino ◽  
Yvonne Boose ◽  
Zamin A. Kanji ◽  
Piotr Kupiszewski ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Condensed Phase ◽  
Atmospheric Aerosols ◽  
Aerosol Particles ◽  
Ice Crystals ◽  
Ice Formation ◽  
Similar Amount ◽  
Residual Material ◽  
History Of ◽  
Phase Water

Abstract It has been known that aerosol particles act as nuclei for ice formation for over a century and a half (see Dufour). Initial attempts to understand the nature of these ice nucleating particles were optical and electron microscope inspection of inclusions at the center of a crystal (see Isono; Kumai). Only within the last few decades has instrumentation to extract ice crystals from clouds and analyze the residual material after sublimation of condensed-phase water been available (see Cziczo and Froyd). Techniques to ascertain the ice nucleating potential of atmospheric aerosols have only been in place for a similar amount of time (see DeMott et al.). In this chapter the history of measurements of ice nucleating particles, both in the field and complementary studies in the laboratory, are reviewed. Remaining uncertainties and artifacts associated with measurements are described and suggestions for future areas of improvement are made.

scholarly journals Identification of the Aerosol Types over Athens, Greece: The Influence of Air-Mass Transport

2010 ◽  
Vol 2010 ◽  
pp. 1-15 ◽  
Author(s):  
D. G. Kaskaoutis ◽  
P. G. Kosmopoulos ◽  
H. D. Kambezidis ◽  
P. T. Nastos
Keyword(s):  
Winter Season ◽  
Saharan Dust ◽  
Dust Particles ◽  
Hysplit Model ◽  
Air Mass ◽  
Back Trajectories ◽  
Air Masses ◽  
Local Pollution ◽  
Coarse Mode ◽  
Aerosol Types

Aerosol optical depth at 550 nm () and fine-mode (FM) fraction data from Terra-MODIS were obtained over the Greater Athens Area covering the period February 2000–December 2005. Based on both and FM values three main aerosol types have been discriminated corresponding to urban/industrial aerosols, clean maritime conditions, and coarse-mode, probably desert dust, particles. Five main sectors were identified for the classification of the air-mass trajectories, which were further used in the analysis of the ( and FM data for the three aerosol types). The HYSPLIT model was used to compute back trajectories at three altitudes to investigate the relation between -FM and wind sector depending on the altitude. The accumulation of local pollution is favored in spring and corresponds to air masses at lower altitudes originating from Eastern Europe and the Balkan. Clean maritime conditions are rare over Athens, limited in the winter season and associated with air masses from the Western or Northwestern sector. The coarse-mode particles origin seems to be more complicated proportionally to the season. Thus, in summer the Northern sector dominates, while in the other seasons, and especially in spring, the air masses belong to the Southern sector enriched with Saharan dust aerosols.

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