Impacts of atmospheric

aerosols and air pollution in

Northern Eurasia and

their dynamics

Irina N. SokolikSchool of Earth and Atmospheric Sciences

Georgia Institute of Technology

Atlanta, GA, USA

Why Northern Eurasia?

• The world’s largest sources of major aerosol

types and air pollutants => strong regional and

global signals (via long-range transport,

teleconnection)

• Distinct trends in sources and spatial and

temporal variability (due to region-specific

climatic, economical and political changes)

• The regional nature of tropospheric aerosols

Intergovernmental Panel on Climate Change (IPCC, 2007)

Global mean radiative forcing (W/m2): 2005 relative to 1750

Climate radiative forcing of atmospheric aerosols

can enhance or rival warming caused by GHGs

Complexity of tropospheric

aerosols:

• different types (distinct

sources, varying emissions,

differing physical and chemical

processes, fine and coarse size

modes)

•short lifetime (up to a few

weeks)

• heterogeneous distribution of

sources and varying transport

pathways

• aging (changes during

transport)

• anthropogenic vs. natural

aerosols

• light absorbing vs. light non-

absorbing aerosols

• many parameters are needed

to characterize aerosols

Direct radiative forcing by individual aerosol components (W/m2):

Sulfates -0.4 (+/- 0.2) Nitrates -0.1 (+/-0.2)

Fossil fuel OC -0.05 (+/- 0.005) Fossil fuel BC +0.2 (+/- 0.15)

Biomass burning +0.03 (+/-0.12) Dust -0.1 (+/-0.2) from -0.3 to +0.1

Aerosols are hard to model

Kinne et al. (2006)

AeroCom intercomparison of GCMs

With some tuning, most GCMs can reproduce the global annual mead AOD

Aerosols in Earth system models

Max Planck Institute – Earth System Model

(MPI-ESM), Stier et al. (2006)

External and internal mixtures of main

aerosol types

Evolving size distribution and composition

Global annual mean aerosol optical depth

retrieved from MPI-ESM vs. AVHRR

Mishchenko et al.(2006)

Over oceans only

Only cloud-free sky

AOD = natural + anthropogenic aerosols

Max Planck Institute – Earth System Model

(MPI-ESM), Stier et al. (2006)

Global “dimming” paradigm:

aerosol-induced reduction in downward surface solar radiation

Trend (%/10YR) Data of global (direct+diffuse) solar radiation from

160 FSU actinometric stations, 1960 – 1990;

Abakumova et al. (1996)

!!!! Net effect of {Aerosols +clouds +H2O} + surface albedo

Solar dimming impact on soil

moisture trends

Robock and Li (2007):

• Aerosol induced-dimming

controls soil moisture

increases (cannot be

explained by precipitation

and T alone)

• Small effect of CO2 trends

Dimming and brightening in China

Qian et al. (2003)

Regional to global linkages

Sources of BC?

Koch and Hansen (2005):

Industrial and biofuel combustion

in Southern Asia are a major

source of BC in the Arctic

Stohl (2006):

Europe and northern Asia are the

main sources

Asian Dust ->Arctic

Boreal Biomass burning -> Arctic

Frequency and intensity?

Trends in aerosol optical depth in the Arctic

Barrow, Alaska

Emissions of PM from stationary sources in 1988

(thousand tons)

0

200

400

600

800

1000

1200

1400

1600

1980 1981 1982 1983 1984 1985 1986 1987 1988

0

200

400

600

800

1000

1200

1400

1600

1980 1981 1982 1983 1984 1985 1986 1987 1988

Data from Annual Bulletins on Air Pollution in the USSR cities and Industrial Centres, 1980-1990; Shahgedanova and Burt (1994)

0

500

1000

1500

2000

2500

3000

3500

1980 1981 1982 1983 1984 1985 1986 1987 1988

Western Siberia

Eastern Siberia

Kazakhstan

Aerosols-energy-hydrological cycle linkages

• Direct and indirect radiative effect

• Effects on precipitation (via clouds)

• Deposition of light absorbing aerosols (soot and dust) on snow/ice

(via snow/ice albedo feedback)

Dust effect on precipitation

Dust promotes precipitation locally

over desert regions

Modeling study using NASA GISS

AGCM (resolution 40x50), considered

only surface radiative forcing

mechanism, no dust-cloud

interactions

Miller et

al.(2004)

Aral dust promotes precipitationCase study of NOAA-AVHRR data of

Aral dust

Rudich et al.

(2002)

Dust suppresses precipitationCase study of NOAA-AVHRR and

TRMM data of Saharan dust

Rosenfeld et al.

(2001)

dust promotes precipitationAir parcel modelingYin et al.(2002)

Wurzler et al.

(2000)

CONCLUSIONCOMMENTSREFERENCE

Dust promotes precipitation locally

over desert regions

Modeling study using NASA GISS

AGCM (resolution 40x50), considered

only surface radiative forcing

mechanism, no dust-cloud

interactions

Miller et

al.(2004)

Aral dust promotes precipitationCase study of NOAA-AVHRR data of

Aral dust

Rudich et al.

(2002)

Dust suppresses precipitationCase study of NOAA-AVHRR and

TRMM data of Saharan dust

Rosenfeld et al.

(2001)

dust promotes precipitationAir parcel modelingYin et al.(2002)

Wurzler et al.

(2000)

CONCLUSIONCOMMENTSREFERENCE

Sokolik et al.

“Climatology” of Asian dust

A combined effect of variability of met parameters and land cover/land use change

Kurosaki et al. (2006)

Asian Dust Data Bank

Kurosaki and Sokolik

Asian Dust Data Bank

Kurosaki and Sokolik

Long-range transport of Asian dust from

TOMS AI and MODIS AOD

Apr 6

Apr 7Apr 8

Apr 9 Apr 10Apr 11

Apr 12

Apr 6

Apr 7

Apr 8,9

Apr 10Apr 11 Apr 12

MODIS AOD > 0.4

TOMS AI > 1.7

“The perfect dust storm” in 2001

Darmenova et al.(2005)

Asian Dust Data Bank

Coupled regional modeling system

Mesoscale Model

WRF

(RegCM)

Dust Module

DuMo

Terrestrial

preprocessor

Adjustable water/land cover mask to

reproduce different historical LULC

scenarios in Central and East Asia;

Data base of land properties for dust

emission

Flexible nesting capability (down to 1 km)

Driven by assimilated winds (NCEP or

ECMWF)

Physically based-dust production schemes

(coupled with the land model)

Physically based-treatments of size-

resolved dust composition

Radiative feedback

Dust/cloud/precipitation coupling

Aerosol - ecosystem-hydrological cycle linkages

Aerosols

Decrease surface SW radiation

and increase LW radiation

Decrease SW direct radiation but may

increase SW diffuse radiation =>

alter photosynthetically active radiation

(PAR) (400-700 nm)

Other important processes: aerosol deposition on vegetation;

aerosol impacts on O3 and rain acidity, etc.

Positive or negative

feedbacks?

Acid rain

Forested area

(in million ha)

Growing stock

(in billion m3)

Sulfur

European Russia 21.5 2.8

Asian Russia 210.0 24.5

Total 231.5 27.3

Nitrogen

European Russia 1 0.2

Asian Russia 87 11.4

Total 88 11.6

Forest area and growing stock at risk from

sulfur and nitrogen depositions in Russia

(Nilsson and Shvidenko, 1999)

Adverse impacts of aerosols on human well-being

Fine aerosol

particles are

responsible for

causing the greatest

harm to human

health. Inhaled deep

into the lungs, they

can cause breathing

and respiratory

problems, irritation,

inflammation and

cancer

Particle size

Aerosols cause decrease in solar

radiation in the photosynthetically

active region (0.4-0.7 µµµµm) reducing

photosynthesis

Health impact Agriculture impacts

Reduction in

productivity

Deposition of particles on the

plants shields solar radiation

NEESPI FRC AAAPNEESPI FRC AAAP

• Venue: School of Earth and Atmospheric Sciences (EAS)

Georgia Institute of Technology, Atlanta, USA

• Leaders:

Irina Sokolik, Robert Dickinson, Judith Curry

• Two-fold Objectives: � Conduct, facilitate, and promote research aimed at improved understanding of interactions between changing aerosols, air pollutants and the Earth systems in Northern Eurasia

� Education and training

NEESPI FRC on

Atmospheric Aerosol and Air Pollution

• 14 funded proposals relevant to aerosol/air pollution studies

Science foci:

– Impact of wind-blown desert dust on ecosystem functioning, precipitation, and energy budget

– Climate, fires and emissions

– Impact of aerosols on hydrological cycle in the Arctic (IPY endorsed)

– Air quality and human health:

Trans-Siberian observations (TROICA),

POLLEN (allergic pollen in Europe)

• Many (???) NEESPI-related projects

The roles of aerosols in the Earth system

Many challenges of “do-it- all” models

Impact on the

radiative energy

balance

Impact on clouds

and precipitation

Impact on major

biogeochemical

cycles

Impact on

socioeconomic

systems and

human well-

being

Impact on

atmospheric

composition and

chemistry

Aerosol

Impact on

ecosystem

functioning

Only TOA forcing

is included in IPCC

Summary

Climate change and population development in the 21th century are expected to cause increases in atmospheric aerosol concentrations. There is a clear need for improved knowledge of interactions between changing atmospheric aerosols and the Earth Systems to increase confidence in our understanding of how and why the climate and environment have changed and to develop improved predictive capabilities for integrated assessments of climate change in the future.

Aerosol- and air pollution-induced interactions and feedbacks in the land biosphere-atmosphere system and their role in climate change…

• What are the key aerosol- and air pollution-induced processes and feedbacks that have been affecting the energy, water and carbon fluxes over Northern Eurasia (their mechanisms, temporal and spatial scales)?

• How will the future changes in terrestrial ecosystem dynamics, climate and human factors affect the above processes in Northern Eurasia?

Focus of NEESPIFocus of NEESPI