Aerosol and Climate Modeling- BHallier (NASA)

8/6/2019 Aerosol and Climate Modeling- BHallier (NASA)

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Aerosol and ClimateModelingA summary of existing aerosol and cloud chamber

research facilities, factors that influence aerosol

behavior, current aerosol modeling capabilities and

shortfalls, and requirements for a state-of-the-art NASA

research facility to model aerosol effects on climate

change

Current global circulation models have resolutions too large to accurately

estimate how climate change will affect our planet. As we spend valuable time

estimating future climate properties with inaccurate models, we are approaching

a critical tipping point where we must choose to act and save our planet, or

continue our current path to self-destruction. The Intergovernmental Panel on

Climate Change estimates a 4-11 degree rise in temperature by 2100. This

temperature rise will melt arctic and polar sea ice displacing 1/3 of the human

population, cause warming and acidification of the ocean leading to the extinctionof countless species, and feed numerous feedback loops which will ensure

continued warming of the planet. In order to save our planet we must

comprehensively research and understand the factors that influence our climate.

This packet summarizes the capabilities of existing research facilities, as of 2010,

that attempt to quantify the effects of aerosols on our climate, factors that

influence aerosol behavior, methods to improve GCM and RCM accuracy, and the

capabilities that a NASA aerosol facility will need to investigate the properties of

aerosols that are essential to accurately forecasting our Earths future.

2010

Bradley Hallier

LaRC

7/23/2010


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Aerosol and Cloud Chamber Research

Facilities

This section details the majority of facilities that focus on aerosol research around the world. Manyof the research facilities below have multiple chambers for aerosol study with different capabilities.

Each chambers known research capabilities are listed. Some research facilities have more than one

aerosol research chamber, and some facilities are grouped under their sponsoring program.

1. DOE Facilities at Pacific Northwest National Lab Atmospheric Research Chamber

Aerosol formation and transformation Role of aerosols as condensation nuclei Aerosol processes associated with anthropogenic, biogenic, and biomass burning

compounds

Ice Nucleation Chamber

Artificial clouds under precisely controlled temperature and super saturation conditions Isolation of particles from aerosol to study ice nucleation Portable to study ambient aerosols

2. UC Riverside Atmospheric Process Lab Aerosol formation and evolution in the troposphere Consists of two 90 m3 reactors No cloud process abilities Supported by EPA

3. DRI Ice Physics Lab Static diffusion chamber Ice nucleation and electrification studies Produces study on ice habits on glass fiber Not highly subscribed

4. DRI Storm Peak LabSTORMVEx

Location: 3220 m high mountain in Colorado Equipment for airborne cloud research


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Will study situ cloud and precipitation property measurementsISPA

Studies effects of pollution aerosols on snow growth by riming and snowfall amounts onthe ground

Results have implications for water resources in the inner mountain west Supported by Nevada, NSF, DOE

5. NASA GRC Particulate Aerosol Lab (SE-11) Provided aerosol and ice particle measurements during recent ACCRI tests Flow through chamber (N2) Pressure: Sea level to 50,000 ft Temp: Ambient to -70C Humidity: 0-100% (RHi) Chamber Velocity: 0.5 to 3 m/s 3 Windows and panel for probe insertion Capability for exhaust introduction Studied effect of soot and sulfuric acid on ice formation

6. Leipzig Aerosol Cloud Interaction Chamber Investigates physical and chemical processes in the polluted troposphere Flow through chamber Flow tube 1-10 m in length Temp: -40C min Used for CCN studies

7. AIDA Location: Germany Size: 4 m diameter, 7 m high, 84.5 m3 Pressure: 0.01 to 1013 hPa Temp: 183K to 323K Uses air as working fluid Ice saturations achieved by expansion Wall temperature actively controlled

Used for both IN and CCN studies Many techniques for generating test aerosols Location: Karlsruhe Institute of Technology Capability for addition of instruments


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8. National Institute of Radiological Sciences Location: Japan Volume: 25 m3 Radon-aerosol chamber Temp: 278-303K Humidity: 30-90% Pressure between inside and outside of chamber can be negative Particle Concentration: 108-1010 m-3

9. Institute of Chemistry and Dynamics of the Geosphere (ICG) Volume: 260 m3 Studies reactions of the surface of aerosols Uses high resolution FTIR spectroscopy to track gas concentrations Equipped with a scanning electrostatic classifier

10. ARM Mobile Facility (AMF) Tracks interaction between clouds and aerosol particles Measures optical, chemical, physical, and cloud activation properties equipped with many additional inlets to enable additional equipment to be added Condensation Nuclei Counter Multiple-Supersaturation Cloud Nuclei and Condensation Nuclei Counter Particle/Soot Absorption Photometer

11. Meteorological Research Institute Cloud Simulation Chamber Location: Tsukuba, Japan 1 pressure vessel and one temperature vessel Volume: 1.4m3 Pressure: 1000 to below 30hPa Temp: 30 to -100C Chamber Velocity: 0 to 30 m/s Studies cloud formation and ice properties

12. Colorado State University

Continuous Flow Diffusion Chamber Studies ice formation on aerosol particles Some funding from NASA


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13. Energy Research Center of the Netherlands Location: Netherlands Used to study the cloud activation of ambient aerosol Very high flow rate (30m3/min) Uses forward scattering spectrometer probe for measuring cloud droplet number

concentration

Uses high-flow cascade impactors for chemical characterization of aerosol Compared the number of cloud droplets created in clean marine air vs. polluted marine

air

14. Vector GmbH Bremen Aerosol Chamber Location: Germany Volume: 9 m3 Used to study -Pinene ozonolysis in the presence of ammonium sulfate or sulfuric acid

seed particles

15. Oak Ridge National Lab Environmental Sciences Division Mission: (1) investigation of particle behavior in the atmosphere and industrial

workplaces, (2) interactions of engineered and anthropogenic pollution particles with

biological systems, and (3) development of advanced instrumentation and

measurement methodology

Relation to Jaguar (largest existing supercomputer) [see below] Funding sources include DOE and DOD

EUropean Supersites for Atmospheric Aerosol Research

(EUSAAR)

1.Aspvreten Research Station (ASP): Location: About 80 km south of Stockholm at the Baltic coast Determines the physical and chemical properties of the aerosol and contains additionalmeteorological instruments as well as basic instrumentation for gaseous compounds

Measures particle size distribution from 10 to 500 nm Particle mass in two fractions, PM10 and PM 2.5 Particle mass, carbonaceous material (Organic Carbon, Elemental Carbon) Black Carbon, soot Meteorological conditions Tracks air pollution levels over time


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2. Zeppelin Research Station (ZEP): Location: Svalbards west coast, 474m above sea level in an undisturbed Arcticenvironment

Owned by the Norwegian Polar Research Institute and is used mostly by the NorwegianInstitute for Atmospheric Research

Performs studies on the atmosphere, snow and ice properties, and Earths energybalance

3. BEO Moussala Research Station (BEO): Location: High mountain in Bulgaria away from pollution Equipped with meteorological instrumentation, O3 and NOx concentration equipment,devices for radio aerosol research, X-ray florescence analysis, neutron and gamma

measurements

Run by the Bulgarian Academy of Science

4. Cabauw Experimental Site for Atmospheric Research (CBW): Location: An agricultural area in the western part of The Netherlands Has a variety of air masses around from clean maritime to continental polluted Measures land atmosphere interaction and cloud, aerosol and radiation interaction Also measures aerosol properties, aerosol optical depth using a CIMEL sun photometer,and aerosol extinction and backscatter profiles using a backscatter lidar

Run by KIMI

5. Finokalia Research Station (FKL): Location: SE Mediterranean away from local sources of pollution Air is representative of synoptic scale atmospheric composition Equipped with in-situ meteorological instrumentation as well as continuousmeasurements of gaseous (O3, CO, NOx, and NOy), particulate (optical properties, chemical

composition, mass, and mass size distribution) and wet deposition

Location has frequent dust events which is ideal for studying the interaction of gaseouscompounds with heterogeneous surfaces (like dust and sea-salt)

Run by the Environmental Chemical Processes Laboratory


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6. Harwell Research Station (HWL): Location: Harwell, United Kingdom Used as a rural station representative of large scale air masses affecting SouthernEngland

Equipped with in-situ meteorological instrumentation as well as continuousmeasurements of gas phase (O3, NOx, SO2) and particulate (mass concentration, size

distribution, chemical composition) pollutants

Run by University of Birmingham

7. High Altitude Research Station Jungfraujoch (JFJ): Location: Jungfraujoch, Switzerland Located far from local pollution sources; well suited to determine the background abovea continental area

Equipped with a full suite of gas phase components (measures both situ and columnproperties), and aerosol measurements are performed by PSI

The station is within clouds 40% of the time, making it well suited for cloud-aerosolinteraction study

Run by the International Foundation High Altitude Research Stations Jungfraujoch andGornergra

8. JRC-Ispra Atmospheric Research Station (JRC): Location: JRC-Ispra, Italy Located tens of kilometers from local sources of pollution and is representative of theregional polluted background

Equipped with in-situ meteorological instrumentation along with continuousmeasurements of gaseous, particulate (optical properties, size distribution, chemical

composition) species

Will use LIDAR in future Run by the Institute for Environment and Sustainability of the EC - DG Joint ResearchCentre


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Modeling Methods and Capabilities

This section was intended to describe the modeling capabilities of current and developing aerosolmodels. Due to limited time this section was stopped in order to work on more pertinent issues in

this paper. Although this section is far from complete, it was still included because it may be added

to at a later time.

1. GOddard Chemistry Aerosol Radiation and Transport (GOCART): Uses the assimilated meteorological fields of the Goddard Earth Observing System DataAssimilation System

Has a resolution of 2 deg latitude by 2.5 deg longitude or 1 deg by 1 deg, and 20-55vertical sigma layers Incorporates Sulfur (from EDGAR data), dust (8 particle sizes), OC and BC (estimatedfrom global fire counts), sea-salt (determines from wind speed)

Tracks transport, chemistry, dry and wet removal, optical thickness

Aerosol TypesThis section covers the major natural and anthropogenic aerosols present in our atmosphere.

Natural:

Mineral Dust:

Mineral dust is composed of soil particles that have entered the atmosphere usually due

to wind (Earth Gauge, n.d.). The origin of 94% of Earths mineral dust aerosols is the northern

hemisphere (Earth Gauge, n.d.). Mineral dust is usually composed of metal oxides (e.g. iron

oxide, aluminum oxide, and magnesium oxide) and clays and carbonates (e.g. calcium carbonate

or limestone) (Earth Gauge, n.d.). The length of time that dust particles are present in the air

depends on their size and the meteorological conditions in their environment. Large particles

tend to undergo dry deposition more quickly than smaller particles because of their larger mass.

There are many methods that aerosols such as dust are removed from the atmosphere, one

being wet deposition. When precipitation occurs in the atmosphere, water can collect the dust

aerosol and deposit it on the ground. Mineral dust in the atmosphere can cause droughts, snow

melt, ocean cooling, and fertilization of algae in the ocean in addition to localized warming of

the atmosphere (Earth Gauge, n.d.).


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Sea Salt:

Sea salt aerosols are the largest contributors to global-mean clear-sky radiative balance

over oceans and can have measurable effects upon cloud radiative properties (Mahowald,

Lamarque, Tie, & Wolff, n.d.). Ice core samples show 2-5 fold changes in surface sea salt

deposition between glacial and interglacial periods, which supports the idea that the climate is

very sensitive to these aerosols (Mahowald, Lamarque, Tie, & Wolff, n.d.). Sea salt entrainment

into clouds is equivalent to surface winds cubed meaning that small changes in wind conditions

can affect salt aerosol concentrations (Mahowald, Lamarque, Tie, & Wolff, n.d.).

Oceanic Organic Matter:

As waves break, they release saltwater aerosols containing highly enriched organic

matter (OM) (Zhou et al., 2008). As OM travels into the atmosphere, it reacts photochemically.

OM is likely an important source of reactive aerosols including OH radical and hydroperoxides

(Zhou et al., 2008). The importance of OM released by the ocean lies in that it has a substantial

impact on tropospheric chemistry including ozone formation, oxidation processes, sulfur cycles,

radiation balance, and climate. Oceanic organic matter is not currently incorporated into models

(Zhou et al., 2008).

Dimethylsulphide:

Dimethylsulphide (DMS) is a considerably large contributor to CCN numbers over the

ocean. DMS is released by planktonic algae in sea water which then enters the atmosphere and

oxidizes to form a sulphate aerosol (Charlson, Lovelock, Andreae, & Warren, 1987). DMS is an

important feature in the CLAW hypothesis which states that as oceans warm, phytoplankton

growth increases which causes an increase in DMS and in turn causes more CCN to form leading

to increased cloud albedo and cooling. Recent research done by MIT has found that

dimethylsulfoniopropionate (DMSP) attracts certain microbes which then consume it and

release DMS into the atmosphere (Massachusetts Institute of Technology, 2010). MITs findings

suggest that microbes are involved heavily in the oceans sulphur and carbon cycles.

Anthropogenic:

Sulfate, Nitrate, Ammonium:

Sulfate particles are a large component of anthropogenic aerosols. It is believed that

sulfate and its associated cations make up to 60% of aerosol mass with a diameter of less than

2.5 m (Penner et al., 1994). The effects of Sulfate, Nitrate, and Ammonium in the atmosphere

are direct backscatter of solar radiation, changes in cloud albedo, and changes in cloud lifetimes

due to modification of CCN numbers (Penner et al., 1994). More data is required to more

accurately estimate the effects of water-soluble inorganic species (i.e. ammonium nitrate); they

are not currently included in models (Penner et al., 1994). SiO2 must also be studied to better


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understand the effects of its fine particles downwind from coal-burning regions such as Asia

(Penner et al., 1994).

Condensed Organic Species:

Sources of organic aerosol species include combustion and atmospheric oxidation of

certain gaseous precursors such as aromatics, cyclic alkenes, and long chain aliphatics (Penner et

al., 1994). The unspeciated organic fraction of the aerosol in rural areas is roughly 24% of the

aerosol mass under 2.5 m in diameter, of which 70% is estimated to be anthropogenic and a

result of combustion (Penner et al., 1994). Concentrations of organic aerosols appear to be

higher in remote ocean locations of the northern atmosphere than in the southern hemisphere,

but it is unknown what fraction of these concentrations is anthropogenic (Penner et al., 1994).

The radiative effects of organic species are very similar to those of Sulfate which are brought

about by modification of CCN behavior and backscatter of solar radiation (Penner et al., 1994).

Black and Elemental Carbon:

BC and EC are the primary light absorbing anthropogenic species. Knowledge of the

impact and distribution of BC and EC on regional and hemispheric scales is small when

compared to our knowledge of sulfates (Penner et al., 1994). Characterization of the

distribution of these carbon species is challenging because they originate from incomplete

combustion and have numerous sources which have varying emission levels (Penner et al.,

1994). The effects of carbon in the atmosphere include direct localized heating of the

atmosphere due to absorption of solar radiation. Absorption of solar radiation in the upper

atmosphere causes a cooling effect on the lower atmosphere, causing changes in the vertical

temperature profile of the atmosphere (Penner et al., 1994). Variations in vertical temperature

profiles cause convection currents which can then alter processes such as the transfer of heat

from the surface to the atmosphere (Penner et al., 1994). Circulation models and precise

calculation of the radiative effects of EC and BC are deficient due to lack of observational data

(Penner et al., 1994). A high priority must be put on measuring the emission of carbon from

locations in Europe due to the lower grade of fuels and lower combustion efficiency levels than

in the United States (Penner et al., 1994).


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Factors That Influence Aerosol BehaviorThis section details factors that influence aerosol lifecycle and behavior in addition to aerosol

dynamics. The factors listed below, obviously, do not include possibly numerous factors that we do

not know about.

Altitude:Altitude is an important factor that influences aerosol behavior in the atmosphere and cloud

formation. Certain cloud types are associated with certain particle sizes which tend to collect at specific

altitudes. Low altitude (< 70,000 ft) cirrus clouds average particulate sizes of 30-300 microns usually

originating from thunderstorm blow off (Davis, 8/26/1988, p. 1). Nacreous clouds (75,000 ft) average 1

micron particle sizes originating from mountain waves (Davis, 8/26/1988, p. 1). Noctilucent clouds

(260,000 ft) average .1-10 micron particle sizes which tend to appear at high latitudes during the

summer (Davis, 8/26/1988, p. 1). Meteoric dust (all altitudes) averages .01-20 microns (Davis,

8/26/1988, p. 1). And aerosols (65-75,000 ft) average .1 microns from events like volcanic eruptions and

sulfate emissions (Davis, 8/26/1988, p. 1).

The size and distribution of aerosols and particulates in the air is important because they have

the ability to degrade LF, cause erosion, and increase the temperature of the atmosphere (Davis,

8/26/1988, p. 1). The altitude of these particles dictates where these effects will occur (i.e. atmospheric

heating or LF degradation).

Moisture (Humidity):Humidity in the atmosphere impacts the optical properties of aerosols, their ability to serve as

CCN and IN, and the length of time that they are present in the atmosphere. As humidity rises, aerosols

serve as nucleation points for clouds, which can either lead to precipitation, or a cloud that is highly

reflective and unable to precipitate. If precipitation occurs, a majority of the aerosol will be removed or

transported to a lower level of the atmosphere through the falling water or ice.

If precipitation does not occur, because the available volume of water is spread over too many

points of nucleation to reach a mass large enough to precipitate, the cloud composition will consist of

very small, reflective droplets which have a high albedo. Highly reflective clouds and water vapor are

important because along with aerosols they reflect 80% of incoming solar radiating back to space (U.S.

Department of Energy Office of Science, 2010, pp. 11-12).

Temperature:Temperature is the driving force for thermophoresis, which is an aerosol transportation method.

Thermophoresis is driven by temperature gradients in a gas medium. The effect of the process inaerosols smaller than the gas mean free path (less than 0.066 m) is the movement of aerosol particles

from the warmer side of the gradient to the cooler side ("Thermophoretic Force and Velocity," n.d.). In

larger particles the process is similar, but more complex because the particle has its own temperature

gradient in addition to the surrounding temperature gradient. The result of both particle gradients is

supplemented in the fact that particle movement is also influenced by the thermal conductivity of the


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surrounding air and particle. As a large particle moves from the warmer side of the gradient to the

cooler side (as small particles do), the particles with high thermal conductivities will lose velocity quickly

due to their quick loss of energy through conductivity, but as a particle with low thermal conductivity

moves into the cooler side of the gradient it maintains its velocity through its resistance to loss of energy

due to quick heat transfer ("Thermophoretic Force and Velocity," n.d.).

Radiation:Radiation affects aerosol characteristics by causing differential heating in the atmosphere which

leads to air currents that have the ability to transport and disperse aerosols over large areas. In

addition, radiation can manipulate the formation and lifetime of clouds. Aerosols have an albedo effect

which reflects a great deal of solar radiation. Black Carbon is an important aerosol that opposes the net

cooling effect of aerosols. Black Carbon absorbs radiation instead of reflecting it which results in

warming. The presence of black Carbon on ice or in the atmosphere causes a decrease in the reflectivity

of radiation and causes the atmosphere to heat (U.S. Department of Energy Office of Science, 2010, pp.

12).

Surface Chemistry:The surface chemistry of an aerosol determines how it reacts in the atmosphere

with other aerosols and particles. Surface chemistry affects the chance of agglomeration

and whether it can dissolve in water or other liquids. Surface chemistry may be modified by

incoming UV radiation. Ozone is important in the creation of OH radicals which are essential

in the oxidation process of a number of particle species in the atmosphere (Moortgat, 2001).

In simple terms, as Ozone undergoes photodissociation due to UV radiation, OH is formed

which then reacts with particles oxidizing them and thereby removing them from the

atmosphere (Moortgat, 2001). [It should be noted that photodegradation and reaction with

OH radicals are known to be the main degradation processes of carbonyl compounds

(Moortgat, 2001).]

Particle Production:Aerosol dynamics influence the growth and development of aerosols in the atmosphere.

Starting as a gas, unstable, quick moving molecules collide with each other forming small clusters. As

the clusters continue their erratic movement, governed by the dynamics of their environment, they

continue collisions and grow to a larger size. Through the process of collisional growth, the particles are

now coagulated molecules. If the atmosphere in which the clusters are present is at a high temperature,

the clusters may bond together in the process of sintering to form large stable particles, or if heat is not

high enough to sustain sintering, the clusters will grow into larger agglomerates through condensationalgrowth.


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Dynamics:Understanding aerosol dynamics is essential in modeling the life cycle of clouds. Known factors

that play into aerosol dynamics are:

Vertical Air Motions:

Vertical air motions transport aerosols through the layers of the atmosphere andare very important in cloud life cycle. In order to have realistic models of vertical air

motions in the atmosphere more information must be collected to understand the behavior

and speed of the currents. The effects of energy fluxes and radiation on air motions must

be quantified (U.S. Department of Energy Office of Science, 2010, pp. 19).

Entrainment:

Entrainment is the uptake of environmental air into clouds. Entrainment affects the

velocity and buoyancy of convectional updrafts, controlling the upward movement of

clouds. The entrainment process is not well understood, and is difficult to observe. Water

vapor and humidity are important in the entrainment process. For accurate modeling ofentrainment in the atmosphere, extensive knowledge of humidity levels is required (U.S.

Department of Energy Office of Science, 2010, pp. 19).

Convective Initiation:

Convective initiation is a process that transports clouds and their accompanying

aerosols. It marks the beginning of the cloud life cycle where many cloud producing

processes converge. Convective initiation poses a challenge to incorporate into GCMs

because it is associated with many other processes, including gust fronts and troposphere

thermodynamic structure, which still need more investigation to understand (U.S.

Department of Energy Office of Science, 2010, pp. 19-20).

Agglomeration:

Agglomeration is a crucial phenomenon between aerosol particles that must be

thoroughly understood to create an accurate GCM. As particles move, they often collide

with other particles which can lead to the formation of a larger particle through adherence

(Huang, Lin, & Wang, 2007). Particle size has important impacts on the properties of the

aerosol particle (e.g. optical depth and heating potential), which is why GCMs must

incorporate this dynamic process. As particles grow their ability to serve as CCN and IN

changes which in turn can completely alter the degree to which other factors such as

electrostatics, temperature, radiation and atmospheric turbulence have on the aerosol.

Atmospheric Turbulence:

Atmospheric turbulence causes aerosol particles to cluster in areas of low

vorticity (Collins & Keswani, 2004). This effect has important effects on aerosol

processes because high concentrations of aerosol particles in a small area greatly


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increases the particle to particle collision rate and in turn allows for a higher rate of

agglomeration. Similarly, the process of water droplet agglomeration in clouds,

which leads to precipitation, occurs because of turbulence within the cloud (Shaw,

2003).

Important Info: Turbulence causes formation of small-scale droplet

inhomogeneities, and it also increases the relative droplet velocity. In addition, the

turbulence affects the hydrodynamic droplet interaction. The latter increases the

rate of droplet collisions. These effects are of a great importance for understanding

of rain formation in atmospheric clouds. In particular, these effects can cause the

droplet spectrum broadening and acceleration of raindrop formation (Elperin,

Kleeorin, Liberman, Lvov, & Rogachevskii, 2007).

Electrostatics:Most aerosols have some degree of an electric charge which affects their

behavior. Aerosols can attain a charged state through direct ionization, static

electrification, electrolytic effects (liquids of high dielectric constant exchange ionswith metals), contact electrification, spray electrification, frictional electrification,

collisions with ion, diffusion, and field charging (Ahmadi, n.d.). Electrostatics can

cause aerosol particulates to diffuse or condense into a small area, increasing the

chance of particle on particle collisions and agglomeration. Furthermore, Aerosol

electrostatics can influence the effects that other forces like temperature gradients

and electromagnetic radiation can have on the aerosols behavior (Ahmadi, n.d.).

Electrostatic effects on aerosol travel: Violent disruption of a liquid surface

- such as occurs when seawater droplets are created by the breaking of waves or the

bursting of the thinning, roughly hemispherical bubble-films created when air

bubbles rise to the ocean surface: or when air bubbles burst at the surface of lakes,ponds and other stretches of water - is accompanied by significant electric charging

of the huge numbers of droplets so produced (Latham & Wick, 2002). The resulting

charge, which usually affects droplets from 0.1 to several micrometers, is great

enough to overpower the force of gravity and allows to droplets to rise into the

atmosphere (Latham & Wick, 2002). This process is an extremely efficient

mechanism of injecting biological aerosol into the atmosphere (Latham & Wick,

2002).


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How to Improve Climate Modeling

Presently, global climate modeling does not completely incorporate all the vital interactions

between aerosols, clouds, and the dynamics of the atmosphere. Important factors which influence

aerosols such as atmospheric turbulence, electrostatics, and feedback loops are not understood well

enough to create accurate high resolution models. Existing GCMs have resolutions greater than 100 km

and error factors too high to allow true regional climate models. In order to generate usable GCMs that

will help us estimate the future effects of pollution on our climate, we have to comprehensively

understand all the influencing factors that affect clouds, aerosols, and atmosphere dynamics.

To create regional climate models (with accuracies of a few kilometers), models must include

circulation characteristics, boundary-layer dynamics, surface atmosphere coupling, radiative transfer,

and cloud microphysics (Bader et al., 2008). Regional models must have clearly defined regional scales

and the ability to incorporate the effects of phenomena (e.g. tropical storms, effects of mountains, jet

circulations, and ocean-land interaction) (Bader et al., 2008). The knowledge gained through

incorporating the effects of these phenomena will be beneficial for GCMS as well, because the data

acquired from the RCMs can be integrated into GCMs, improving their accuracy (Bader et al., 2008).

No single model appears best through observations because different models display superior

performance depending on the location examined (Bader et al., 2008). Using a number of models

together may yield the best and most accurate estimation results.

Tradeoffs exist between regional and global climate models. While GCMs coarsely simulate

atmospheric events over large areas, they lack the ability to accurately look at a regional scale. At the

same time, an RCM can, for the most part, accurately track events on a small regional scale, but up

scaling may lead to event extremes that are over exaggerated (Bader et al., 2008). For these reasons,

GCMs and RCMs must be used collectively to estimate atmospheric events and properties.

Characteristics of a NASA Facility

In order to produce climate models that can estimate the future characteristics of our climate,

more data must be collected to better comprehend how aerosols affect cloud properties and the earths

energy budget. Current aerosol and cloud chamber facilities study:

Aerosol properties Aerosol formation and transformation Role of aerosols as condensation nuclei Effects of aerosols on ice nucleation Effects of soot and sulfuric acid on ice formation Physical and chemical processes in the polluted troposphere


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Land-atmosphere interaction and cloud, aerosol, and radiation interactionThe most advanced aerosol research facility, Aerosols Interaction and Dynamics in the

Atmosphere, is located at the Karlsruhe Institute of Technology in Germany. AIDA has a chamber with a

4m diameter and 7m height. It has a temperature range of 183K to 323K, and a pressure range of 0.01

to 1013 hPa. AIDA is used primarily for the study of IN and CCN studies and has many methods forgenerating test aerosols. It also has the capability for a wide range of instruments.

A future NASA facility would need a large enough volume to study the effects turbulence and

convection on aerosols. Additionally, incorporation of electrostatics would be necessary. Factors that

should be studied at the new facility:

Effects of radiation on aerosol particles Effects of convection currents on aerosol growth and development Effects of turbulence and electrostatics on aerosol behavior and agglomeration Effects of entrainment of aerosol particles into clouds on the cloud life cycle Effects of bio-aerosols on aerosol behavior and their radiative effects Evolution of aerosol particles relating to the many forces that act upon them (e.g. radiation,

turbulence, reaction with other aerosols)

The new NASA facility would need to study the above and calculate their influence on more well

understood topics like aerosol effects on CCN and IN. In order to develop practical GCMs all aerosol

influences must be quantified in relation to each other.

Current Computing Power (for modeling)

Computing power is expected to be 108

better in 20 years. Currently supercomputers are

running at petaFLOPS but soon they will have the ability to run at the exaFLOPS level, the level necessary

to computationally generate higher resolution regional GCMs. The 2 most advanced supercomputers

currently are listed below:

1. Oak Ridge National Laboratory (Jaguar)

Built by Cray Inc. Capable of performing at 1.75 petaFLOPS Cores: 224162 Rmax= 1759.00 TFlops Rpeak= 2331.00 TFlops Relation to ORNL Environmental Sciences Division (See Aerosol Facilities Above)


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2. National Supercomputing Centre in Shenzhen (Nebulae) Built by Dawning Capable of performing at 1.271 petaFLOPS Cores: 120640 Rmax= 1271.00 TFlops Rpeak= 2984.30 TFlops


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References

Aerosol dynamics. (n.d.).Aerosol basics. Retrieved July 21, 2010, from http://www.aerosols.wustl.edu/

education/AerosolBasics/Aerosol%20dynamics.htm

Ahmadi, G. (n.d.). Electrodynamics. Retrieved from Clarkson University website:

http://web2.clarkson.edu/projects/crcd/me637/downloads/P_Electrodynamics.pdf

Bader, D. C., Covey, C., Gutowski, W. J., Jr., Held, I. M., Kunkel, K. E., Miller, R. L., . . . Zhang, M. H. (2008,

July 31). Climate models: An assessment of strengths and limitations. Retrieved from Climate

Models: An Assessment of Strengths and Limitations website: http://www.climatescience.gov/

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