MATRIX (Multiconfiguration Aerosol TRacker of mIXing state): an aerosol microphysical module for global atmospheric models

Abstract. A new aerosol microphysical module MATRIX, the Multiconfiguration Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS) climate model (ModelE) are described. This module, which is based on the quadrature method of moments (QMOM), represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol population, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble aerosol populations. A detailed model description and results of box-model simulations of various aerosol population configurations are presented. The box model experiments demonstrate the dependence of cloud activating aerosol number concentration on the aerosol population configuration; comparisons to sectional models are quite favorable. MATRIX is incorporated into the GISS climate model and simulations are carried out primarily to assess its performance/efficiency for global-scale atmospheric model application. Simulation results were compared with aircraft and station measurements of aerosol mass and number concentration and particle size to assess the ability of the new method to yield data suitable for such comparison. The model accurately captures the observed size distributions in the Aitken and accumulation modes up to particle diameter 1 μm, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment. This is more likely due to oversimplifications of the representation of sea salt emissions – sea salt emissions are only calculated for two size classes – than to inherent limitations of MATRIX.

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MATRIX (Multiconfiguration Aerosol TRacker of mIXing state): an aerosol microphysical module for global atmospheric models

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-9931-2008 ◽

2008 ◽

Vol 8 (3) ◽

pp. 9931-10003 ◽

Cited By ~ 1

Author(s):

S. E. Bauer ◽

D. Wright ◽

D. Koch ◽

E. R. Lewis ◽

R. McGraw ◽

...

Keyword(s):

Particle Size ◽

Climate Model ◽

Particle Diameter ◽

Global Scale ◽

Number Concentration ◽

Model Description ◽

Carbonaceous Aerosols ◽

Mixing State ◽

Cloud Drop ◽

Detailed Model

Abstract. A new aerosol microphysical module MATRIX, the Multiconfiguation Aerosol TRacker of mIXing state, and its application in the Goddard Institute for Space Studies (GISS) climate model (ModelE) is described. This module, which is based on the quadrature method of moments (QMOM), represents nucleation, condensation, coagulation, internal and external mixing, and cloud-drop activation and provides aerosol particle mass and number concentration and particle size information for up to 16 mixed-mode aerosol populations. Internal and external mixing among aerosol components sulfate, nitrate, ammonium, carbonaceous aerosols, dust and sea-salt particles are represented. The solubility of each aerosol mode, which is explicitly calculated based on its soluble and insoluble components, enables calculation of the dependence of cloud drop activation on the microphysical characterization of multiple soluble modes. A detailed model description and results of box-model simulations of various mode configurations are presented. The number concentration of aerosol particles activated to cloud drops depends on the mode configuration. Simulations on the global scale with the GISS climate model are evaluated against aircraft and station measurements of aerosol mass and number concentration and particle size. The model accurately captures the observed size distributions in the aitken and accumulation modes up to particle diameter 1 μm, in which sulfate, nitrate, black and organic carbon are predominantly located; however the model underestimates coarse-mode number concentration and size, especially in the marine environment.

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Size-resolved cloud condensation nuclei (CCN) activity and closure analysis at the HKUST Supersite in Hong Kong

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-10267-2014 ◽

2014 ◽

Vol 14 (18) ◽

pp. 10267-10282 ◽

Cited By ~ 43

Author(s):

J. W. Meng ◽

M. C. Yeung ◽

Y. J. Li ◽

B. Y. L. Lee ◽

C. K. Chan

Keyword(s):

Particle Size ◽

Hong Kong ◽

Atmospheric Aerosols ◽

Cloud Condensation Nuclei ◽

Particle Diameter ◽

Volume Ratio ◽

Condensation Nuclei ◽

Mixing State ◽

Scanning Mobility Particle Sizer ◽

The Mean

Abstract. The cloud condensation nuclei (CCN) properties of atmospheric aerosols were measured on 1–30 May 2011 at the HKUST (Hong Kong University of Science and Technology) Supersite, a coastal site in Hong Kong. Size-resolved CCN activation curves, the ratio of number concentration of CCN (NCCN) to aerosol concentration (NCN) as a function of particle size, were obtained at supersaturation (SS) = 0.15, 0.35, 0.50, and 0.70% using a DMT (Droplet Measurement Technologies) CCN counter (CCNc) and a TSI scanning mobility particle sizer (SMPS). The mean bulk size-integrated NCCN ranged from ~500 cm−3 at SS = 0.15% to ~2100 cm−3 at SS = 0.70%, and the mean bulk NCCN / NCN ratio ranged from 0.16 at SS = 0.15% to 0.65 at SS = 0.70%. The average critical mobility diameters (D50) at SS = 0.15, 0.35, 0.50, and 0.70% were 116, 67, 56, and 46 nm, respectively. The corresponding average hygroscopic parameters (κCCN) were 0.39, 0.36, 0.31, and 0.28. The decrease in κCCN can be attributed to the increase in organic to inorganic volume ratio as particle size decreases, as measured by an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The κCCN correlates reasonably well with κAMS_SR based on size-resolved AMS measurements: κAMS_SR = κorg × forg + κinorg × finorg, where forg and finorg are the organic and inorganic volume fractions, respectively, κorg = 0.1 and κinorg = 0.6, with a R2 of 0.51. In closure analysis, NCCN was estimated by integrating the measured size-resolved NCN for particles larger than D50 derived from κ assuming internal mixing state. Estimates using κAMS_SR show that the measured and predicted NCCN were generally within 10% of each other at all four SS. The deviation increased to 26% when κAMS was calculated from bulk PM1 AMS measurements of particles because PM1 was dominated by particles of 200 to 500 nm in diameter, which had a larger inorganic fraction than those of D50 (particle diameter < 200 nm). A constant κ = 0.33 (the average value of κAMS_SR over the course of campaign) was found to give an NCCN prediction within 12% of the actual measured values. We also compared NCCN estimates based on the measured average D50 and the average size-resolved CCN activation ratio to examine the relative importance of hygroscopicity and mixing state. NCCN appears to be relatively more sensitive to the mixing state and hygroscopicity at a high SS = 0.70% and a low SS = 0.15%, respectively.

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The global aerosol-climate model ECHAM-HAM, version 2: sensitivity to improvements in process representations

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-8911-2012 ◽

2012 ◽

Vol 12 (19) ◽

pp. 8911-8949 ◽

Cited By ~ 225

Author(s):

K. Zhang ◽

D. O'Donnell ◽

J. Kazil ◽

P. Stier ◽

S. Kinne ◽

...

Keyword(s):

Organic Matter ◽

Water Uptake ◽

Climate Model ◽

Organic Aerosols ◽

Lower Troposphere ◽

Cloud Microphysics ◽

Number Concentration ◽

Sea Salt ◽

Microphysics Scheme ◽

Aerosol Mass

Abstract. This paper introduces and evaluates the second version of the global aerosol-climate model ECHAM-HAM. Major changes have been brought into the model, including new parameterizations for aerosol nucleation and water uptake, an explicit treatment of secondary organic aerosols, modified emission calculations for sea salt and mineral dust, the coupling of aerosol microphysics to a two-moment stratiform cloud microphysics scheme, and alternative wet scavenging parameterizations. These revisions extend the model's capability to represent details of the aerosol lifecycle and its interaction with climate. Nudged simulations of the year 2000 are carried out to compare the aerosol properties and global distribution in HAM1 and HAM2, and to evaluate them against various observations. Sensitivity experiments are performed to help identify the impact of each individual update in model formulation. Results indicate that from HAM1 to HAM2 there is a marked weakening of aerosol water uptake in the lower troposphere, reducing the total aerosol water burden from 75 Tg to 51 Tg. The main reason is the newly introduced κ-Köhler-theory-based water uptake scheme uses a lower value for the maximum relative humidity cutoff. Particulate organic matter loading in HAM2 is considerably higher in the upper troposphere, because the explicit treatment of secondary organic aerosols allows highly volatile oxidation products of the precursors to be vertically transported to regions of very low temperature and to form aerosols there. Sulfate, black carbon, particulate organic matter and mineral dust in HAM2 have longer lifetimes than in HAM1 because of weaker in-cloud scavenging, which is in turn related to lower autoconversion efficiency in the newly introduced two-moment cloud microphysics scheme. Modification in the sea salt emission scheme causes a significant increase in the ratio (from 1.6 to 7.7) between accumulation mode and coarse mode emission fluxes of aerosol number concentration. This leads to a general increase in the number concentration of smaller particles over the oceans in HAM2, as reflected by the higher Ångström parameters. Evaluation against observation reveals that in terms of model performance, main improvements in HAM2 include a marked decrease of the systematic negative bias in the absorption aerosol optical depth, as well as smaller biases over the oceans in Ångström parameter and in the accumulation mode number concentration. The simulated geographical distribution of aerosol optical depth (AOD) is better correlated with the MODIS data, while the surface aerosol mass concentrations are very similar to those in the old version. The total aerosol water content in HAM2 is considerably closer to the multi-model average from Phase I of the AeroCom intercomparison project. Model deficiencies that require further efforts in the future include (i) positive biases in AOD over the ocean, (ii) negative biases in AOD and aerosol mass concentration in high-latitude regions, and (iii) negative biases in particle number concentration, especially that of the Aitken mode, in the lower troposphere in heavily polluted regions.

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Inversion of droplet aerosol analyzer data for long-term aerosol–cloud interaction measurements

Atmospheric Measurement Techniques ◽

10.5194/amt-7-877-2014 ◽

2014 ◽

Vol 7 (4) ◽

pp. 877-886 ◽

Cited By ~ 1

Author(s):

M. I. A. Berghof ◽

G. P. Frank ◽

S. Sjogren ◽

B. G. Martinsson

Keyword(s):

Particle Size ◽

Particle Diameter ◽

Cloud Droplet ◽

Number Concentration ◽

Cloud Droplets ◽

Data Set ◽

Size Dependent ◽

First Results ◽

Ambient Particle ◽

Droplet Size Distributions

Abstract. The droplet aerosol analyzer (DAA) was developed to study the influence of aerosol properties on clouds. It measures the ambient particle size of individual droplets and interstitial particles, the size of the dry (residual) particles after the evaporation of water vapor and the number concentration of the dry (residual) particles. A method was developed for the evaluation of DAA data to obtain the three-parameter data set: ambient particle diameter, dry (residual) particle diameter and number concentration. First results from in-cloud measurements performed on the summit of Mt. Brocken in Germany are presented. Various aspects of the cloud–aerosol data set are presented, such as the number concentration of interstitial particles and cloud droplets, the dry residue particle size distribution, droplet size distributions, scavenging ratios due to cloud droplet formation and size-dependent solute concentrations. This data set makes it possible to study clouds and the influence of the aerosol population on clouds.

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A GCM study of organic matter in marine aerosol and its potential contribution to cloud drop activation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-5675-2007 ◽

2007 ◽

Vol 7 (2) ◽

pp. 5675-5700

Author(s):

G. J. Roelofs

Keyword(s):

Organic Matter ◽

Chemical Composition ◽

Dimethyl Sulfide ◽

Climate Model ◽

Organic Aerosol ◽

Potential Contribution ◽

Marine Aerosol ◽

Mixing State ◽

Cloud Drop ◽

Aerosol Mass

Abstract. With the global aerosol-climate model ECHAM5-HAM we investigate the potential influence of organic aerosol originating from the ocean on aerosol mass and chemical composition and the droplet concentration and size of marine clouds. We present sensitivity simulations in which the uptake of organic matter in the marine aerosol is prescribed for each aerosol mode with varying organic mass and mixing state, and with a geographical distribution and seasonality similar to the oceanic emission of dimethyl sulfide. Measurements of aerosol mass and chemical composition serve to evaluate the representativity of the model initializations. Good agreement with the measurements is obtained when organic matter is added to the Aitken, accumulation and coarse modes simultaneously. Representing marine organics in the model leads to higher cloud drop number concentrations, smaller cloud drop effective radii, and a better agreement with remote sensing measurements. The mixing state of the organics and the other aerosol matter, i.e., internal or external depending on the formation process of aerosol organics, is an important factor for this. We estimate that globally about 75 Tg C yr−1 of organic matter from marine origin enters the aerosol phase. An approximate 35% of this occurs through formation of secondary organic aerosol and 65% through emission of primary particles.

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Spatial and temporal CCN variations in convection-permitting aerosol microphysics simulations in an idealised marine tropical domain

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-3371-2017 ◽

2017 ◽

Vol 17 (5) ◽

pp. 3371-3384 ◽

Cited By ~ 5

Author(s):

Céline Planche ◽

Graham W. Mann ◽

Kenneth S. Carslaw ◽

Mohit Dalvi ◽

John H. Marsham ◽

...

Keyword(s):

Particle Size ◽

High Resolution ◽

Wind Speed ◽

Large Scale ◽

Dimethyl Sulfide ◽

Climate Model ◽

Sea Salt ◽

Limited Area ◽

Strong Wind ◽

Aerosol Composition

Abstract. A convection-permitting limited area model with periodic lateral boundary conditions and prognostic aerosol microphysics is applied to investigate how concentrations of cloud condensation nuclei (CCN) in the marine boundary layer are affected by high-resolution dynamical and thermodynamic fields. The high-resolution aerosol microphysics–dynamics model, which resolves differential particle growth and aerosol composition across the particle size range, is applied to a domain designed to match approximately a single grid square of a climate model. We find that, during strongly convective conditions with high wind-speed conditions, CCN concentrations vary by more than a factor of 8 across the domain (5–95th percentile range), and a factor of ∼  3 at more moderate wind speed. One reason for these large sub-climate-grid-scale variations in CCN is that emissions of sea salt and dimethyl sulfide (DMS) are much higher when spatial and temporal wind-speed fluctuations become resolved at this convection-permitting resolution (making peak wind speeds higher). By analysing how the model evolves during spin-up, we gain new insight into the way primary sea salt and secondary sulfate particles contribute to the overall CCN variance in these realistic conditions, and find a marked difference in the variability of super-micron and sub-micron CCN. Whereas the super-micron CCN are highly variable, dominated by strongly fluctuating sea spray emitted, the sub-micron CCN tend to be steadier, mainly produced on longer timescales following growth after new particle formation in the free troposphere, with fluctuations inherently buffered by the fact that coagulation is faster at higher particle concentrations. We also find that sub-micron CCN are less variable in particle size, the accumulation-mode mean size varying by ∼  20 % (0.101 to 0.123 µm diameter) compared to ∼  35 % (0.75 to 1.10 µm diameter) for coarse-mode particles at this resolution. We explore how the CCN variability changes in the vertical and at different points in the spin-up, showing how CCN concentrations are introduced both by the emissions close to the surface and at higher altitudes during strong wind-speed conditions associated to the intense convective period. We also explore how the non-linear variation of sea-salt emissions with wind speed propagates into variations in sea-salt mass mixing ratio and CCN concentrations, finding less variation in the latter two quantities due to the longer transport timescales inherent with finer CCN, which sediment more slowly. The complex mix of sources and diverse community of processes involved makes sub-grid parameterisation of CCN variations difficult. However, the results presented here illustrate the limitations of predictions with large-scale models and the high-resolution aerosol microphysics–dynamics modelling system shows promise for future studies where the aerosol variations will propagate through to modified cloud microphysical evolution.

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Inversion of droplet aerosol analyzer data for long-term aerosol-cloud interaction measurements

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-6-10269-2013 ◽

2013 ◽

Vol 6 (6) ◽

pp. 10269-10295 ◽

Cited By ~ 1

Author(s):

M. I. A. Berghof ◽

G. P. Frank ◽

S. Sjogren ◽

B. G. Martinsson

Keyword(s):

Particle Size ◽

Particle Diameter ◽

Cloud Droplet ◽

Number Concentration ◽

Cloud Droplets ◽

Size Dependent ◽

First Results ◽

Ambient Particle ◽

Droplet Size Distributions

Abstract. The droplet aerosol analyzer (DAA) was developed to study the influence of aerosol properties on clouds. It measures the ambient particle size of individual droplets and interstitial particles, the size of the dry (residual) particles after the evaporation of water, and the number concentration of the dry (residual) particles. A method was developed for the evaluation of DAA data to obtain the three-parameter dataset: ambient particle diameter, dry (residual) particle diameter and number concentration. First results from in-cloud measurements performed on the summit of Mt. Brocken in Germany are presented. Various aspects of the cloud aerosol dataset are presented, such as the number concentration of interstitial particles and cloud droplets, the dry residue particle size distribution, droplet size distributions, scavenging ratios due to cloud droplet formation and size-dependent solute concentrations. This dataset makes it possible to study clouds and the influence of the aerosol population on clouds.

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Climate model studies of sulphate aerosols and clouds

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.1997.0017 ◽

1997 ◽

Vol 352 (1350) ◽

pp. 221-229 ◽

Cited By ~ 9

Author(s):

A. Jones ◽

A. Slingo

Keyword(s):

Indirect Effect ◽

Climate Model ◽

Number Concentration ◽

Sea Salt ◽

Sulphate Aerosol ◽

Model Studies ◽

Naturally Occurring ◽

Sulphate Aerosols ◽

Hadley Centre ◽

Atmospheric Concentrations

It is generally believed that increases in the atmospheric concentrations of greenhouse gases as a result of man's activities are leading to global warming. It is also believed that the same activities lead to increasing concentrations of sulphate aerosol, which act to cool the climate system and ameliorate the warming. The sulphate cooling may be separated into the direct effect in cloud–free regions and the indirect effect in cloudy regions. This paper summarizes recent work at the Hadley Centre on the indirect effect. Results from two versions of the hadley Centre Climate Model are shown, using various parameterizations linking the amountof sulphate aerosol and the number concentration of droplets in water clouds. These results illustrate the considerable uncertainties in estimating the indirect effect. It is shown that other naturally occurring components of the aerosol population, in particular sea salt, may be important in reducing the magnitude of the indirect effect.

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Spatial and temporal CCN variations in convection-permitting aerosol microphysics simulations in an idealised marine tropical domain

10.5194/acp-2016-826 ◽

2016 ◽

Author(s):

Céline Planche ◽

Graham W. Mann ◽

Kenneth S. Carslaw ◽

Mohit Dalvi ◽

John H. Marsham ◽

...

Keyword(s):

Particle Size ◽

High Resolution ◽

Wind Speed ◽

Large Scale ◽

Climate Model ◽

Cloud Condensation Nuclei ◽

Sea Salt ◽

Limited Area ◽

Convective Conditions ◽

Aerosol Composition

Abstract. A convection-permitting limited area model with periodic lateral boundary conditions and prognostic aerosol microphysics is applied to investigate how concentrations of cloud condensation nuclei (CCN) in the marine boundary layer are affected by high resolution dynamical and thermodynamic fields. The high-resolution aerosol microphysics–dynamics model, which resolves differential particle growth and aerosol composition across the particle size range, is applied on a domain designed to match approximately a single grid square of a climate model. We find that, during strongly convective conditions, CCN concentrations vary by more than a factor of 8 across the domain (5th–95th percentile range), and a factor of ~3 at more moderate wind-speed conditions. One reason for these large sub-climate-grid-scale variations in CCN is that emissions of sea-salt and DMS are much higher when spatial and temporal wind speed fluctuations become resolved at this convection-permitting resolution (making peak wind speeds higher). By analysing how the model evolves during spin-up, we gain new insight into the way primary sea-salt and secondary sulphate particles contribute to the overall CCN variance in these realistic conditions, and find a marked difference in the variability of super-micron and sub-micron CCN. Whereas the super-micron CCN are highly variable, being dominated by strongly fluctuating emitted sea-spray, the sub-micron CCN tend to be steadier, being mainly produced on longer timescales following growth after new particle formation in the free troposphere, with fluctuations inherently buffered by the fact that coagulation is faster at higher particle concentrations. We also find that sub-micron CCN are less variable in particle size, the accumulation mode mean size varying by ~20 % (0.101 to 0.123 µm diameter) compared to ~35 % (0.75 to 1.10 µm diameter) for coarse mode particles at this resolution. We explore how the CCN variability changes in the vertical, and at different points in the spin-up, showing how CCN concentrations are introduced both by the emissions close to the surface, and at higher altitudes during strongly convective conditions. We also explore how the non-linear variation of sea-salt emissions with wind speed propagates into variations in sea-salt mass mixing ratio and CCN concentrations, finding less variation in the latter two quantities due to the longer transport timescales inherent with finer CCN, which sediment more slowly. The complex mix of sources and diverse community of processes involved makes sub-grid parameterization of CCN variations difficult. However, the results presented here illustrate the limitations of predictions with large-scale models and the high-resolution aerosol-dynamics modelling system shows promise for future studies where the aerosol variations will propagate through to modified cloud microphysical evolution.

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Compositions and mixing states of aerosol particles by aircraft observations in the Arctic springtime, 2018

10.5194/acp-2020-1114 ◽

2020 ◽

Author(s):

Kouji Adachi ◽

Naga Oshima ◽

Sho Ohata ◽

Atsushi Yoshida ◽

Nobuhiro Moteki ◽

...

Keyword(s):

Climate Model ◽

Mineral Dust ◽

Model Simulation ◽

Aerosol Particles ◽

Sea Salt ◽

The Arctic ◽

Radiation Balance ◽

Mixing State ◽

Carbonaceous Particles ◽

Airborne Measurements

Abstract. Aerosol particles were collected at various altitudes in the Arctic during the Polar Airborne Measurements and Arctic Regional Climate Model Simulation Project (PAMARCMiP 2018) conducted in the early spring of 2018. The composition, size, number fraction, and mixing state of individual aerosol particles were analyzed using transmission electron microscopy (TEM), and their sources and transport were evaluated by numerical model simulations. We found that sulfate, sea-salt, mineral-dust, K-bearing, and carbonaceous particles were the major aerosol constituents and were internally mixed. The number fraction of mineral-dust and sea-salt particles decreased with increasing altitude. The K-bearing particles increased within a biomass burning (BB) plume at altitudes > 3900 m, which originated from Siberia. Chlorine in sea-salt particles was replaced with sulfate at high altitudes. These results suggest that the sources, transport, and aging of Arctic aerosols largely vary depending on the altitude and airmass history. We also provide the occurrences of solid-particle inclusions (soot, fly-ash, and Fe-aggregate particles), some of which are light-absorbing and potential ice-nucleating particles. Our TEM measurements revealed, for the first time, the detailed mixing state of individual particles at various altitudes in the Arctic. This information facilitates the accurate evaluation of the aerosol influences on Arctic haze, radiation balance, cloud formation, and snow/ice albedo when deposited.

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