The global aerosol–climate model ECHAM6.3–HAM2.3  – Part 1: Aerosol evaluation

Abstract. We introduce and evaluate aerosol simulations with the global aerosol–climate model ECHAM6.3–HAM2.3, which is the aerosol component of the fully coupled aerosol–chemistry–climate model ECHAM–HAMMOZ. Both the host atmospheric climate model ECHAM6.3 and the aerosol model HAM2.3 were updated from previous versions. The updated version of the HAM aerosol model contains improved parameterizations of aerosol processes such as cloud activation, as well as updated emission fields for anthropogenic aerosol species and modifications in the online computation of sea salt and mineral dust aerosol emissions. Aerosol results from nudged and free-running simulations for the 10-year period 2003 to 2012 are compared to various measurements of aerosol properties. While there are regional deviations between the model and observations, the model performs well overall in terms of aerosol optical thickness, but may underestimate coarse-mode aerosol concentrations to some extent so that the modeled particles are smaller than indicated by the observations. Sulfate aerosol measurements in the US and Europe are reproduced well by the model, while carbonaceous aerosol species are biased low. Both mineral dust and sea salt aerosol concentrations are improved compared to previous versions of ECHAM–HAM. The evaluation of the simulated aerosol distributions serves as a basis for the suitability of the model for simulating aerosol–climate interactions in a changing climate.

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The aerosol-climate model ECHAM6.3-HAM2.3: Aerosol evaluation

10.5194/gmd-2018-235 ◽

2018 ◽

Cited By ~ 1

Author(s):

Ina Tegen ◽

David Neubauer ◽

Sylvaine Ferrachat ◽

Colombe Siegenthaler-Le Drian ◽

Isabelle Bey ◽

...

Keyword(s):

Climate Model ◽

Mineral Dust ◽

Sea Salt ◽

Carbonaceous Aerosol ◽

Anthropogenic Aerosol ◽

Aerosol Model ◽

Online Computation ◽

Climate Interactions ◽

Cloud Activation ◽

Aerosol Emissions

Abstract. We introduce and evaluate the aerosol simulations with the global aerosol-climate model ECHAM6.3-HAM2.3, which is the aerosol component of the fully coupled aerosol-chemistry-climate model ECHAM-HAMMOZ. Both the host atmospheric climate model ECHAM6.3 and the aerosol model HAM2.3 were updated from previous versions. The updated version of the HAM aerosol model contains improved parameterizations of aerosol processes such as cloud activation, as well as updated emission fields for anthropogenic aerosol species and modifications in the online computation of sea salt and mineral dust aerosol emissions. Aerosol results from nudged and free running simulations for the 10-year period 2003 to 2012 are compared to various measurements of aerosol properties. While there are regional deviations between model and observations, the model performs well overall in terms of aerosol optical thickness, but may underestimate coarse mode aerosol concentrations to some extent, so that the modeled particles are smaller than indicated by the observations. Sulfate aerosol measurements in the US and Europe are reproduced well by the model, while carbonaceous aerosol species are biased low. Both mineral dust and sea salt aerosol concentrations are improved compared to previous versions of ECHAM-HAM. The evaluation of the simulated aerosol distributions serves as a basis for the suitability of the model for simulating aerosol-climate interactions in a changing climate.

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ModelE2-TOMAS development and evaluation using aerosol optical depths, mass and number concentrations

Geoscientific Model Development Discussions ◽

10.5194/gmdd-7-5831-2014 ◽

2014 ◽

Vol 7 (5) ◽

pp. 5831-5918 ◽

Cited By ~ 2

Author(s):

Y. H. Lee ◽

P. J. Adams ◽

D. T. Shindell

Keyword(s):

Organic Matter ◽

General Circulation ◽

Mineral Dust ◽

Cloud Condensation Nuclei ◽

Circulation Model ◽

Convective Transport ◽

Sea Salt ◽

Computationally Efficient ◽

Anthropogenic Aerosol ◽

Aerosol Model

Abstract. The TwO-Moment Aerosol Sectional microphysics model (TOMAS) has been integrated into the state-of-the-art general circulation model, GISS ModelE2. TOMAS has the flexibility to select a size resolution as well as the lower size cutoff. A computationally efficient version of TOMAS is used here, which has 15 size bins covering 3 nm to 10 μm aerosol dry diameter. For each bin, it simulates the total aerosol number concentration and mass concentrations of sulphate, pure elementary carbon (hydrophobic), mixed elemental carbon (hydrophilic), hydrophobic organic matter, hydrophilic organic matter, sea salt, mineral dust, ammonium, and aerosol-associated water. This paper provides a detailed description of the ModelE2-TOMAS model and evaluates the model against various observations including aerosol precursor gas concentrations, aerosol mass and number concentrations, and aerosol optical depths. Additionally, global budgets in ModelE2-TOMAS are compared with those of other global aerosol models, and the TOMAS model is compared to the default aerosol model in ModelE2, which is a bulk aerosol model. Overall, the ModelE2-TOMAS predictions are within the range of other global aerosol model predictions, and the model has a reasonable agreement with observations of sulphur species and other aerosol components as well as aerosol optical depth. However, ModelE2-TOMAS (as well as the bulk aerosol model) cannot capture the observed vertical distribution of sulphur dioxide over the Pacific Ocean possibly due to overly strong convective transport. The TOMAS model successfully captures observed aerosol number concentrations and cloud condensation nuclei concentrations. Anthropogenic aerosol burdens in the bulk aerosol model running in the same host model as TOMAS (ModelE2) differ by a few percent to a factor of 2 regionally, mainly due to differences in aerosol processes including deposition, cloud processing, and emission parameterizations. Larger differences are found for naturally emitted aerosols such as sea salt and mineral dust. With TOMAS, ModelE2 has three different aerosol models (the bulk aerosol model and modal-based aerosol microphysics model, MATRIX) and allows exploration of the uncertainties associated with aerosol modelling within the same host model, NASA GISS ModelE2.

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Improving the simulation of global aerosol with size-segregated anthropogenic number emissions

10.5194/acp-2017-841 ◽

2017 ◽

Author(s):

Filippo Xausa ◽

Pauli Paasonen ◽

Risto Makkonen ◽

Mikhail Arshinov ◽

Aijun Ding ◽

...

Keyword(s):

Particle Number ◽

Climate Models ◽

Climate Model ◽

Dominant Role ◽

Particle Diameter ◽

Radiation Budget ◽

Size Distributions ◽

Anthropogenic Aerosol ◽

Accumulation Mode ◽

Climate Interactions

Abstract. Climate models are important tools that are used for generating climate change projections, in which aerosol-climate interactions are one of the main sources of uncertainties. In order to quantify aerosol-radiation and aerosol-cloud interactions, detailed input of anthropogenic aerosol number emissions is necessary. However, the anthropogenic aerosol number emissions are usually converted from the corresponding mass emissions in precompiled emission inventories through a very simplistic method depending uniquely on chemical composition, particle size and density, which are defined for a few very wide main source sectors. In this work, the anthropogenic particle number emissions converted from the AeroCom mass in the ECHAM-HAM climate model were replaced with the recently-formulated number emissions from the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS)-model, where the emission number size distributions vary, for example, with respect to the fuel and technology. A special attention in our analysis was put on accumulation mode particles (particle diameter dp > 100 nm) because of (i) their capability of acting as cloud condensation nuclei (CCN), thus forming cloud droplets and affecting Earth's radiation budget, and (ii) their dominant role in forming the coagulation sink and thus limiting the concentration of sub-100 nanometers particles. In addition, the estimates of anthropogenic CCN formation, and thus the forcing from aerosol-climate interactions are expected to be affected. Analysis of global particle number concentrations and size distributions reveal that GAINS implementation increases CCN concentration compared with AeroCom, with regional enhancement factors reaching values as high as 10. A comparison between modeled and observed concentrations shows that the increase in number concentration for accumulation mode particle agrees well with measurements, but it leads to a consistent underestimation of both nucleation mode and Aitken mode (dp > 100 nm) particle number concentrations. This suggests that revisions are needed in the new particle formation and growth schemes currently applied in global modeling frameworks.

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Advancing global aerosol simulations with size-segregated anthropogenic particle number emissions

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-10039-2018 ◽

2018 ◽

Vol 18 (13) ◽

pp. 10039-10054 ◽

Cited By ~ 5

Author(s):

Filippo Xausa ◽

Pauli Paasonen ◽

Risto Makkonen ◽

Mikhail Arshinov ◽

Aijun Ding ◽

...

Keyword(s):

Particle Number ◽

Climate Model ◽

Dominant Role ◽

Particle Diameter ◽

Radiation Budget ◽

Size Distributions ◽

Anthropogenic Aerosol ◽

Accumulation Mode ◽

Climate Interactions ◽

Gains Model

Abstract. Climate models are important tools that are used for generating climate change projections, in which aerosol–climate interactions are one of the main sources of uncertainties. In order to quantify aerosol–radiation and aerosol–cloud interactions, detailed input of anthropogenic aerosol number emissions is necessary. However, the anthropogenic aerosol number emissions are usually converted from the corresponding mass emissions in pre-compiled emission inventories through a very simplistic method depending uniquely on chemical composition, particle size and density, which are defined for a few, very wide main source sectors. In this work, the anthropogenic particle number emissions converted from the AeroCom mass in the ECHAM-HAM climate model were replaced with the recently formulated number emissions from the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS) model. In the GAINS model the emission number size distributions vary, for example, with respect to the fuel and technology. Special attention was paid to accumulation mode particles (particle diameter dp > 100 nm) because of (i) their capability of acting as cloud condensation nuclei (CCN), thus forming cloud droplets and affecting Earth's radiation budget, and (ii) their dominant role in forming the coagulation sink and thus limiting the concentration of sub-100 nm particles. In addition, the estimates of anthropogenic CCN formation, and thus the forcing from aerosol–climate interactions, are expected to be affected. Analysis of global particle number concentrations and size distributions reveals that GAINS implementation increases CCN concentration compared with AeroCom, with regional enhancement factors reaching values as high as 10. A comparison between modeled and observed concentrations shows that the increase in number concentration for accumulation mode particles agrees well with measurements, but it leads to a consistent underestimation of both nucleation mode and Aitken mode (dp < 100 nm) particle number concentrations. This suggests that revisions are needed in the new particle formation and growth schemes currently applied in global modeling frameworks.

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Recent pronounced weakening of Asia summer monsoon over the past 450 years

10.5194/egusphere-egu2020-6332 ◽

2020 ◽

Author(s):

Yu Liu ◽

Wenju Cai

Keyword(s):

Summer Monsoon ◽

Large Scale ◽

Climate Model ◽

Ring Width ◽

Future Projection ◽

Anthropogenic Aerosol ◽

Northern Margin ◽

The Past ◽

Detection And Attribution ◽

Aerosol Emissions

Affecting a multitude of ecological and agricultural systems, the Asia summer monsoon (ASM) is essential for biodiversity and the food security of billions of people. Understanding past changes of the ASM is important for the detection and attribution of its recent evolution and future projection in the context of global warming. However, proxy-based, high-resolution reconstructions of the ASM prior to the period of instrumental measurements that started in the 1950s in China are still missing. Here, we use an ensemble of ten tree-ring width chronologies from the northern margin of the ASM to estimate ASM strength back to 1566 AD. The reconstruction not only reveals severe large-scale droughts in 1586/87 and 1759, but also negative anomalies during persistent locus plagues in the 1860s. The record also shows an unprecedented decrease in ASM since the mid-20th century. Simulations from a coupled climate model suggest that the recent ASM decline could have been induced by increased anthropogenic aerosol emissions over the Northern Hemisphere.

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An integrated modeling study on the effects of mineral dust and sea salt particles on clouds and precipitation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-23959-2010 ◽

2010 ◽

Vol 10 (10) ◽

pp. 23959-24014 ◽

Cited By ~ 1

Author(s):

S. Solomos ◽

G. Kallos ◽

J. Kushta ◽

M. Astitha ◽

C. Tremback ◽

...

Keyword(s):

Air Quality ◽

Mineral Dust ◽

Eastern Mediterranean ◽

Atmospheric Modeling ◽

Sea Salt ◽

Cloud Formation ◽

Dust Particles ◽

Limited Area ◽

Aerosol Cloud ◽

Climate Interactions

Abstract. The amount of airborne particles that will nucleate and form cloud droplets under specific atmospheric conditions, depends on their number concentration, size distribution and chemical composition. Aerosol is affected by primary particle emissions, gas-phase precursors, their transformation and interaction with atmospheric constituents, clouds and dynamics. A comprehensive assessment of these interactions requires an integrated approach; most studies however decouple aerosol processes from cloud and atmospheric dynamics and cannot account for all the feedbacks involved in aerosol-cloud-climate interactions. This study addresses aerosol-cloud-climate interactions with the Integrated Community Limited Area Modeling System (ICLAMS) that includes online parameterization of the physical and chemical processes between air quality and meteorology. ICLAMS is an extended version of the Regional Atmospheric Modeling System (RAMS) and it has been designed for coupled air quality – meteorology studies. Model sensitivity tests for a single-cloud study as well as for a case study over the Eastern Mediterranean illustrate the importance of aerosol properties in cloud formation and precipitation. Mineral dust particles are often coated with soluble material such as sea-salt, thus exhibiting increased CCN efficiency. Increasing the percentage of salt-coated dust particles by 15% in the model resulted in more vigorous convection and more intense updrafts. The clouds that were formed extended about 3 km higher and the initiation of precipitation was delayed by one hour. Including on-line parameterization of the aerosol effects improved the model bias for the twenty-four hour accumulated precipitation by 7%. However, the spatial distribution and the amounts of precipitation varied greatly between the different aerosol scenarios. These results indicate the large portion of uncertainty that remains unresolved and the need for more accurate description of aerosol feedbacks in atmospheric models and climate change predictions.

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Constraining ice nuclei freezing efficiency using cloud phase observations together with climate models.

10.5194/egusphere-egu21-8478 ◽

2021 ◽

Author(s):

Diego Villanueva

Keyword(s):

Black Carbon ◽

Climate Models ◽

Climate Model ◽

Mineral Dust ◽

Dust Aerosol ◽

Strong Constraint ◽

Aerosol Model ◽

Aerosol Cloud Interactions ◽

Thermodynamic Phase ◽

The Impact

Aerosol-cloud interactions are an important source of uncertainty in current climate models. In particular, the role of mineral dust and soot particles in cloud glaciation is poorly understood. This lack of understanding leads to high uncertainty in climate predictions.To estimate the global co-variability between mineral dust aerosol and cloud glaciation, we combined an aerosol model reanalysis with satellite retrievals of cloud thermodynamic phase. Our results confirmed that the cloud thermodynamic phase increases with higher mineral dust concentrations.To better understand and quantify the impact of ice-nucleating particles on cloud glaciation, it is crucial to have a reliable estimation of the hemispheric and seasonal contrast in cloud top phase, which is believed to result from the higher dust aerosol loading in boreal spring. For this reason, we locate and quantify these contrasts by combining three different A-Train cloud-phase products for the period 2007-2010. These products rely on a spaceborne lidar, a lidar-radar synergy, and a radiometer-polarimeter synergy. We used these observations to constrain the droplet freezing in the ECHAM-HAM climate model. After tuning, the model leads to more realistic cloud-top-phase contrasts and a dust-driven glaciation effect of 0.14 &#177; 0.13 Wm&#8722;2 between 30&#8211;60&#176;N. Our results show that using observations of cloud-top phase contrasts provide a strong constraint for ice formation in mixed-phase clouds and a weak constraint for the associated impact on radiation and precipitation.Besides mineral dust, it has been under debate whether black carbon also contributes to cloud glaciation. Therefore, we studied the cloud top phase retrieved by CALIOP during the Australian wildfires in 2020. After repeating the tuning strategy for black carbon, we were able to replicate the increase in ice cloud frequency observed during the wildfires.

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The Effects of Anthropogenic Aerosol Emissions from Chile and Mexico in ECHAM-HAMMOZ

10.5194/egusphere-egu2020-9976 ◽

2020 ◽

Author(s):

Tuuli Miinalainen ◽

Harri Kokkola ◽

Kari E. J. Lehtinen ◽

Thomas Kühn

Keyword(s):

Climate Model ◽

Cloud Condensation Nuclei ◽

Cloud Droplet ◽

Radiative Properties ◽

Reference Scenario ◽

Climatic Effects ◽

Anthropogenic Aerosol ◽

Regional Effect ◽

Radiative Balance ◽

Aerosol Emissions

In this research project we studied the climatic effects of anthropogenic aerosol emissions originating from Chile and Mexico. In particular, we studied black carbon (BC), organic carbon (OC) and sulfur dioxide (SO2).By using aerosol-climate model ECHAM6.3.0-HAM2.3-MOZ1.0, we analyzed how each aerosol species affects the local cloud properties and radiative balance in the atmosphere. As we here are interested in the maximum impact, we simulated each aerosol species with separate model runs. The reference scenario (BASE) was simulated with the full representation of anthropogenic aerosol emissions from the ECLIPSEV6a emission inventory for the year 2015.Then, we constructed otherwise identical scenarios but the anthropogenic aerosol emissions from Chile and Mexico for each aerosol type were removed (NO_BC, NO_OC and NO_SO2).&#160;The results indicate that for Chile the sulfur emissions seem to have the greatest impact on both cloud condensation nuclei (CCN) and cloud droplet number concentration. This result is plausible since there the SO2 emissions are much higher than BC and OC emissions. For Mexico, the OC emissions had the most notable effect on CCN, but the cloud droplets are more affected by the SO2 emissions. When looking at the radiative properties, we found out that the direct effects were rather minor compared to semi-direct and indirect effects. This indicates that aerosol-cloud interactions have much larger regional effect on radiation than the aerosol direct effect.

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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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Spatial distributions and seasonal cycles of aerosol climate effects in India seen in global climate-aerosol model

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-18031-2013 ◽

2013 ◽

Vol 13 (7) ◽

pp. 18031-18067 ◽

Cited By ~ 1

Author(s):

S. V. Henriksson ◽

J.-P. Pietikäinen ◽

A.-P. Hyvärinen ◽

P. Räisänen ◽

K. Kupiainen ◽

...

Keyword(s):

Radiative Forcing ◽

Global Climate ◽

Seasonal Cycles ◽

Spatial Distributions ◽

Seasonal Temperature ◽

Anthropogenic Aerosol ◽

Aerosol Model ◽

Aerosol Radiative Forcing ◽

Northern India ◽

Aerosol Emissions

Abstract. Climate-aerosol interactions in India are studied by employing the global climate-aerosol model ECHAM5-HAM and the GAINS inventory for anthropogenic aerosol emissions. Seasonal cycles and spatial distributions of radiative forcing and the temperature and rainfall responses are presented for different model setups. While total aerosol radiative forcing is strongest in the summer, anthropogenic forcing is considerably stronger in winter than in summer. Local seasonal temperature anomalies caused by aerosols are mostly negative with some exceptions, e.g. Northern India in March–May and the eastern Himalayas in September–November. Rainfall increases due to the elevated heat pump (EHP) mechanism and decreases due to solar dimming effects are studied. Aerosol light absorption does increase rainfall significantly in Northern India, but effects due to solar dimming and circulation work to cancel the increase. The total aerosol effect on rainfall is negative when considering all effects if assuming that aerosols have cooled the Northern Indian Ocean by 0.5 °K compared to the equator.

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