Prediction and observation of cloud processing of the aerosol size distribution by a band of cumulus

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

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New trajectory driven aerosol and chemical process model: chemical and aerosol Lagrangian model (CALM)

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-15197-2010 ◽

2010 ◽

Vol 10 (6) ◽

pp. 15197-15261

Author(s):

P. Tunved ◽

D. G. Partridge ◽

H. Korhonen

Keyword(s):

Size Distribution ◽

Process Model ◽

Winter Season ◽

Lagrangian Model ◽

Cloud Formation ◽

Aerosol Size Distribution ◽

Cloud Processing ◽

Primary Reactions ◽

Average Size ◽

Good Agreement

Abstract. A new Chemical and Aerosol Lagrangian Model (CALM) have been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61°51' N, 24°17' E) over a time period of two years, 2000–2001. The model shows good agreement with measurements throughout most of the year, but fails in reproducing the aerosol properties during the winter season, resulting in poor agreement between model and measurements especially during December–January. Nevertheless, through the rest of the year both trends and magnitude of modal concentrations show good agreement with observation, as do the monthly average size distribution properties. The model is also shown to capture individual nucleation events to a certain degree. This indicates that nucleation largely is controlled by the availability of nucleating material (as prescribed by the [H2SO4]), availability of condensing material (in this model 15% of primary reactions of monoterpenes (MT) are assumed to produce low volatile species) and the properties of the size distribution (more specifically, the condensation sink). This is further demonstrated by the fact that the model captures the annual trend in nuclei mode concentration. The model is also used, alongside sensitivity tests, to examine which processes dominate the aerosol size distribution physical properties. It is shown, in agreement with previous studies, that nucleation governs the number concentration while transport from clean areas takes place. It is also shown that primary number emissions almost exclusively govern the CN concentration when air from Central Europe is advected north over Scandinavia. We also show that biogenic emissions have a large influence on the amount of potential CCN observed over the boreal region, as shown by the agreement between observations and modeled results for the receptor SMEAR II, Hyytiälä, during the studied period.

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CCN activation and cloud processing in sectional aerosol models with low size resolution

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-2561-2005 ◽

2005 ◽

Vol 5 (9) ◽

pp. 2561-2570 ◽

Cited By ~ 16

Author(s):

H. Korhonen ◽

V.-M. Kerminen ◽

K. E. J. Lehtinen ◽

M. Kulmala

Keyword(s):

Size Distribution ◽

Large Scale ◽

Reference Model ◽

Cloud Model ◽

Cloud Droplet ◽

Anthropogenic Sources ◽

Aerosol Size Distribution ◽

Droplet Growth ◽

Cloud Droplets ◽

Cloud Processing

Abstract. We investigate the influence of low size resolution, typical to sectional aerosol models in large scale applications, on cloud droplet activation and cloud processing of aerosol particles. A simplified cloud model with five approaches to determine the fraction of activated particles is compared with a detailed reference model under different atmospheric conditions. In general, activation approaches which assume a distribution profile within the critical model size sections predict the cloud droplet concentration most accurately under clean and moderately polluted conditions. In such cases, the deviation from the reference simulations is below 15% except for very low updraft velocities. In highly polluted cases, the concentration of cloud droplets is significantly overestimated due to the inability of the simplified model to account for the kinetic limitations of the droplet growth. Of the profiles examined, taking into account the local shape of the particle size distribution is the most accurate although in most cases the shape of the profile has little relevance. While the low resolution cloud model cannot reproduce the details of the out-of-the-cloud aerosol size distribution, it captures well the amount of sulphate produced in aqueous-phase reactions as well as the distribution of the sulphate between the cloud droplets. Overall, the simplified cloud model with low size resolution performs well for clean and moderately polluted regions that cover most of the Earth's surface and is therefore suitable for large scale models. It can, however, show uncertainties in areas with strong pollution from anthropogenic sources.

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New trajectory-driven aerosol and chemical process model Chemical and Aerosol Lagrangian Model (CALM)

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-10161-2010 ◽

2010 ◽

Vol 10 (21) ◽

pp. 10161-10185 ◽

Cited By ~ 10

Author(s):

P. Tunved ◽

D. G. Partridge ◽

H. Korhonen

Keyword(s):

Size Distribution ◽

Process Model ◽

Winter Season ◽

Lagrangian Model ◽

Cloud Formation ◽

Aerosol Size Distribution ◽

Cloud Processing ◽

Primary Reactions ◽

Average Size ◽

Good Agreement

Abstract. A new Chemical and Aerosol Lagrangian Model (CALM) has been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61° 51' N, 24° 17' E) over a time period of two years, 2000–2001. The model shows good agreement with measurements throughout most of the year, but fails in reproducing the aerosol properties during the winter season, resulting in poor agreement between model and measurements especially during December–January. Nevertheless, through the rest of the year both trends and magnitude of modal concentrations show good agreement with observation, as do the monthly average size distribution properties. The model is also shown to capture individual nucleation events to a certain degree. This indicates that nucleation largely is controlled by the availability of nucleating material (as prescribed by the [H2SO4]), availability of condensing material (in this model 15% of primary reactions of monoterpenes (MT) are assumed to produce low volatile species) and the properties of the size distribution (more specifically, the condensation sink). This is further demonstrated by the fact that the model captures the annual trend in nuclei mode concentration. The model is also used, alongside sensitivity tests, to examine which processes dominate the aerosol size distribution physical properties. It is shown, in agreement with previous studies, that nucleation governs the number concentration during transport from clean areas. It is also shown that primary number emissions almost exclusively govern the CN concentration when air from Central Europe is advected north over Scandinavia. We also show that biogenic emissions have a large influence on the amount of potential CCN observed over the boreal region, as shown by the agreement between observations and modeled results for the receptor SMEAR II, Hyytiälä, during the studied period.

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CCN activation and cloud processing in simplified sectional aerosol models with low size resolution

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-4871-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 4871-4892

Author(s):

H. Korhonen ◽

V.-M. Kerminen ◽

K. E. J. Lehtinen ◽

M. Kulmala

Keyword(s):

Size Distribution ◽

Large Scale ◽

Reference Model ◽

Cloud Model ◽

Cloud Droplet ◽

Aerosol Size Distribution ◽

Droplet Growth ◽

Distribution Profile ◽

Cloud Droplets ◽

Cloud Processing

Abstract. We investigate the influence of low size resolution, typical to sectional aerosol models in large scale applications, on cloud droplet activation and cloud processing of aerosol particles. A simplified cloud scheme with five approaches to determine the fraction of activated particles is compared with a detailed reference model under different atmospheric conditions. In general, activation approaches which assume a distribution profile within the critical model size sections predict the cloud droplet concentration most accurately under clean and moderately polluted conditions. In such cases, the deviation from the reference simulations is below 15% except for very low updraft velocities. In highly polluted cases, the concentration of cloud droplets is significantly overestimated due to the inability of the simplified scheme to account for the kinetic limitations of the droplet growth. Of the profiles examined, taking into account the local shape of the particle size distribution is the most accurate although in most cases the shape of the profile has little relevance. While the low resolution cloud model cannot reproduce the details of the out-of-the-cloud aerosol size distribution, it captures well the amount of sulphate produced in aqueous-phase reactions as well as the distribution of the sulphate between the cloud droplets. Overall, the simplified cloud scheme with low size resolution performs well for clean and moderately polluted regions that cover most of the Earth's surface and is therefore suitable for large scale models.

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Aerosol size distribution measurements at four Nordic field stations: identification, analysis and trajectory analysis of new particle formation bursts

Tellus B ◽

10.3402/tellusb.v59i3.16995 ◽

2007 ◽

Vol 59 (3) ◽

Author(s):

Miikka Dal Maso ◽

Larisa Sogacheva ◽

Pasi P. Aalto ◽

Ilona Riipinen ◽

Mika Komppula ◽

...

Keyword(s):

Size Distribution ◽

Trajectory Analysis ◽

Particle Formation ◽

Aerosol Size Distribution ◽

New Particle Formation ◽

Identification Analysis ◽

Field Stations

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Observation of aerosol size distribution and new particle formation under different air masses arriving at the northwesternmost South Korean island in the Yellow Sea

Atmospheric Research ◽

10.1016/j.atmosres.2021.105537 ◽

2021 ◽

Vol 255 ◽

pp. 105537

Author(s):

Jong-Uk Park ◽

Hyun-Jae Kim ◽

Jinsoo Choi ◽

Jin-Soo Park ◽

Junghwa Heo ◽

...

Keyword(s):

Size Distribution ◽

Yellow Sea ◽

Particle Formation ◽

The Yellow Sea ◽

Aerosol Size Distribution ◽

New Particle Formation ◽

Air Masses ◽

South Korean

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Evaluating model parameterizations of submicron aerosol scattering and absorption with in situ data from ARCTAS 2008

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-9435-2016 ◽

2016 ◽

Vol 16 (14) ◽

pp. 9435-9455 ◽

Cited By ~ 8

Author(s):

Matthew J. Alvarado ◽

Chantelle R. Lonsdale ◽

Helen L. Macintyre ◽

Huisheng Bian ◽

Mian Chin ◽

...

Keyword(s):

Optical Properties ◽

Size Distribution ◽

Aerosol Size Distribution ◽

Visible Radiation ◽

Submicron Aerosol ◽

In Situ Data ◽

Aerosol Absorption ◽

Aerosol Scattering ◽

The Impact

Abstract. Accurate modeling of the scattering and absorption of ultraviolet and visible radiation by aerosols is essential for accurate simulations of atmospheric chemistry and climate. Closure studies using in situ measurements of aerosol scattering and absorption can be used to evaluate and improve models of aerosol optical properties without interference from model errors in aerosol emissions, transport, chemistry, or deposition rates. Here we evaluate the ability of four externally mixed, fixed size distribution parameterizations used in global models to simulate submicron aerosol scattering and absorption at three wavelengths using in situ data gathered during the 2008 Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign. The four models are the NASA Global Modeling Initiative (GMI) Combo model, GEOS-Chem v9-02, the baseline configuration of a version of GEOS-Chem with online radiative transfer calculations (called GC-RT), and the Optical Properties of Aerosol and Clouds (OPAC v3.1) package. We also use the ARCTAS data to perform the first evaluation of the ability of the Aerosol Simulation Program (ASP v2.1) to simulate submicron aerosol scattering and absorption when in situ data on the aerosol size distribution are used, and examine the impact of different mixing rules for black carbon (BC) on the results. We find that the GMI model tends to overestimate submicron scattering and absorption at shorter wavelengths by 10–23 %, and that GMI has smaller absolute mean biases for submicron absorption than OPAC v3.1, GEOS-Chem v9-02, or GC-RT. However, the changes to the density and refractive index of BC in GC-RT improve the simulation of submicron aerosol absorption at all wavelengths relative to GEOS-Chem v9-02. Adding a variable size distribution, as in ASP v2.1, improves model performance for scattering but not for absorption, likely due to the assumption in ASP v2.1 that BC is present at a constant mass fraction throughout the aerosol size distribution. Using a core-shell mixing rule in ASP overestimates aerosol absorption, especially for the fresh biomass burning aerosol measured in ARCTAS-B, suggesting the need for modeling the time-varying mixing states of aerosols in future versions of ASP.

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