Aerosol Outflows and Their Interactions with Gaseous Species in East Asia during Springtime, 2001: Three-Dimensional Model Study Combining Observations

Youhua Tang1, Gregory R. Carmichael1, John H. Seinfeld2, Donald Dabdub3, Rodney J. Weber4, Barry Huebert5, Antony D. Clarke5, Gakuji Kurata6, Itsushi Uno7, Jung-Hun Woo1, David G.

Streets8, Chul-Han Song4, Adrian Sandu9, Theodore L. Anderson10, Robert W. Talbot11 and Jack E. Dibb11

1. Center for Global and Regional Environmental Research, University of Iowa2. Dept. of Chemical Engineering and Environmental Science Engineering,

California Institute of Technology

3. Dept. of Mechanical and Aerospace Engineering, U. of California at Irvine4. School of Earth and Atmospheric Sciences, Georgia Institute of Technology5. School of Ocean and Earth Science and Technology, University of Hawaii

6. Dept. of Ecological Engineering, Toyohashi University of Technology, Japan 7. Research Institute for Applied Mechanics, Kyushu University, Japan8. Decision and Information Sciences Division, Argonne National Laboratory9. Dept. of Computer Science, Virginia Technical University10. Dept. of Atmospheric Science, University of Washington at Seattle11. Dept. of Earth Sciences, University of New Hampshire

Framework of Chemical Mechanism

3332

24223

NODust

HNO NODust

NO

SODust

SO 1.5ODust

O

To represent the involvement of dust in heterogeneous chemistry, we define the dust surface fresh ratio as

active

activefresh Ca

NOCaCaSOCaD 234 )(

where Caactive is the amount of dust active calcium that is

available for heterogeneous reactions:

Cloud fieldDobson O3

On-line TUV

Aerosol Optical

Properties

Gas-phase absorptio

n

Tropospheric O 3

Photolysis Rates

AerosolEquilibrium Module

SCAPE

Gaseous ReactionsSAPRC-99

HeterogeneousReactions (Dust)

Gas-A

erosol E

quilib

rium

interaction

Gaseous Loss

Dust su

rface

satu

ratio

n

Aeroso

l Pro

duction

Four aerosol size bins are used: 0.1µm-0.3µm, 0.3µm-1.0µm, 1.0µm-2.5µm, and 2.5µm-10µm (referred to as bins 1 to 4, respectively).

TA

S T

otal Ca (µ

g/std m

3)

Ca Increase

Sim

ulated

Total C

a (µg/std

m3

)

Ca Increase

Irregular Points

Re-Colored in Coarse Dust Fresh RatioDuring dust events of all C-130 flights, sulfate and nitrate coarse ratios show different correlations under different dust loading, represented by the Ca concentrations. When dust loading increased, the correlation became less varied and converge to a certain point related to dust coarse ratio. Both model and measurements show the similar trend. The simulation also show some points do not follow this trend. For these points, nitrate and sulfate coarse ratios are linearly related. Re-colored in coarse dust fresh ratio, these points were identifies as fresh dust loading. When dust was very fresh, nitrate and sulfate did not repel each other, since follow the similar uptake mechanism.

0 2 4 6 8T I M E (G M T )

2 0

3 0

4 0

5 0

6 0

7 0

8 0

O3 (

pp

bv)

0

2000

4000

6000

8000

Alt

itu

de

(m)

ObservedNORMALNODUSTFULLFlight Altitude

0 2 4 6 8T IM E (G M T )

0

5E-005

0.0001

0.00015

0.0002

0.00025

OH

(p

pb

v)

0

2000

4000

6000

8000

Alt

itu

de

(m)

NORMALNODUSTFULLFlight Altitude

Three Simulations: NODUST: without dustNORMAL: consider dust radiative impact

FULL: consider both heterogeneous and radiative impacts

Dust influences on Gaseous Species along C-130 Flight 6

0 2 4 6 8 10T IM E (G M T )

0

2

4

6

Fin

e A

mm

oniu

m (

ug/

std

m3 )

0

2000

4000

6000

8000

Alt

itu

de

(m)

PILS ObservedSim ulated with DustSim ulated without DustFlight Altitude

0 2 4 6 8 10T IM E (G M T )

0

0.2

0.4

0.6

Du

sr F

resh

Rat

ios

0

2000

4000

6000

8000

Alt

itu

de

(m)

Fine Dust Fresh RatioCoarse Dust Fresh RatioFlight Altitude

0 0.2 0.4 0.6 0.8 1M o d e le d R a tio s

0

1000

2000

3000

4000

5000

6000

7000

Alt

itud

e (m

)

Fine Dust Fresh RatioCoarse Dust Fresh RatioSulfate Fine RatioNitrate Fine RatioAmmonia Aerosol Ratio

0 4 8 12Io n C o nc e n tr a tio n s (u g /s td m 3)

0

1000

2000

3000

4000

5000

6000

7000

Alt

itud

e (m

)

Simulated Fine CaSimulated Coarse CaPILS Fine CaMOI Coarse CaSimulated Fine CO3Simulated Coarse CO3

C-130 Flight 8 encountered aged dust Dust did not influence the sub-micron sulfate, but significantly increased the super-micron sulfate concentration. Sub-micron dust ages faster than the super-micron dust.

9 9 1 0 0 1 0 1 1 0 2 1 0 3 1 0 4J u lian D a y (G M T )

0

0.2

0.4

0.6

0.8

1

Ion

Fin

e R

atio

s an

d T

otal

Dus

t F

resh

Rat

io

0

1000

2000

3000

4000

AG

L (

m)

Sulfate Fine RatioNitrate Fine RatioDust Fresh RatioAltitude (AGL)Longitude

9 0

1 0 0

1 1 0

1 2 0

1 3 0

Lon

gitu

de

9 9 1 0 0 1 0 1 1 0 2 1 0 3 1 0 4J u lia n D a y (G M T )

0

4

8

12

16

20

Fin

e Io

ns

(ug/

std

m3 )

CalciumAmmoniumNitrateSulfate

9 9 1 0 0 1 0 1 1 0 2 1 0 3 1 0 4J u lia n D a y (G M T )

0

2

4

6

8

Coa

rse

Ion

s (u

g/st

d m

3 )

CalciumAmmoniumNitrateSulfate

Extracted model results along trajectory B (shown left) illustrating the dust aging process and composition variation.

0 2 4 6 8T IM E (G M T )

0

2

4

6

8

Fin

e C

alci

um (

ug/s

td m

3 )

0

2000

4000

6000

8000

Alt

itu

de

(m)

PILS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

5

10

15

20

25

Tot

al C

alci

um (

ug/s

td m

3 )

0

2000

4000

6000

8000

Alt

itu

de

(m)

TAS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

0.2

0.4

0.6

0.8

Fin

e M

agn

esiu

m (

ug/

std

m3 )

0

2000

4000

6000

8000

Alt

itu

de

(m)

PILS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

1

2

3

Tot

al M

agne

sium

(u

g/st

d m

3 )

0

2000

4000

6000

8000

Alt

itu

de (

m)

TAS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

4

8

12

16

Fin

e S

ulf

ate

(ug/

std

m3 )

0

2000

4000

6000

8000

Alt

itu

de

(m)

PILS ObservedSim ulated with DustSim ulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

4

8

12

16

Tot

al S

ulfa

te (

ug/s

td m

3 )

0

2000

4000

6000

8000

Alt

itud

e (m

)

TAS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

1

2

3

4

5

6

7

Fin

e N

itra

te (

ug/s

td m

3 )

0

2000

4000

6000

8000

Alt

itud

e (m

)

PILS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

2

4

6

8

10

Tot

al N

itra

te (

ug/

std

m3 )

0

2000

4000

6000

8000

Alt

itud

e (m

)

TAS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

2

4

6

Fin

e A

mm

oniu

m (

ug/

std

m3 )

0

2000

4000

6000

8000

Alt

itud

e (m

)

PILS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

1

2

3

4

5

Tot

al A

mm

oniu

m (

ug/

std

m3 )

0

2000

4000

6000

8000

Alt

itu

de

(m)

TAS ObservedSimulated with DustSimulated without DustFlight Altitude

0 2 4 6 8T IM E (G M T )

0

500

1000

1500

2000

2500

Coa

rse

Du

st (

ug/

std

m3 )

0

2000

4000

6000

8000

Fli

ght

Alt

itud

e (m

)

O b serv ed C oa rse P a rtic leS im u la ted C oa rse D u stF lig h t A ltitu d e

O b served an d S im u la ted D u st in C -130 F lig h t #6 (04 /11 /2001 )

0 2 4 6 8T IM E (G M T )

0

0.0002

0.0004

0.0006

0.0008

AO

E @

550

nm

(/m

)

0

2000

4000

6000

8000

Fli

ght

Alt

itud

e (m

)

O b serv ed A O ES im u la ted A O E w ith D u stS im u la ted A O E w ith o u t D u stF lig h t A ltitu d e

O b serv ed a n d S im u la ted A O E in C -13 0 F lig h t # 6 (0 4 /1 1 /2 00 1 )

Measurements Compared to the Simulations with and without Dust along C-130 Flight 6

Simulations with and without dust clearly show the dust influence on secondary aerosols. Dust appearance increased total sulfate and nitrate concentrations, especially increased their coarse portions, but the high Ca loading repelled ammonia uptake. Dust storm also significantly increased aerosol extinction coefficient.

Averaged Dust Concentration (µg/m3) Averaged in the layers below 3km

GMS-5 Dust-Enhanced Image

Simulated Total Dust below 3 km with Weather Stations where Dust Were Reported

Simulated Dust Fresh Ratio in the 400m level Simulated Sulfate Coarse Ratio in the 400m level

C-130 Flight 6 & 7

Trajectory B

Simulated Dust Fresh Ratio DfreshSimulated Sulfate (contour, µg/m3) and its Coarse Ratio (color-coded)

Apr 7

Apr 9

Apr 11

Apr 13

The dust storms occurred from April 4-14, 2001 in East Asia were named “perfect storm”by some ACE-Asia investigators. These dust storms accompanied with cold-air outbreak and were transported eastward. Dusts became aged (shown by dust fresh ratio) when passing over polluted areas, and sulfate increased its coarse ratio. The interaction of dust, secondary aerosols and gaseous species through equilibria and heterogeneous processes significantly affected related species and aerosol size distributions, which was verified by aircrafts (C-130 and Twin Otter), NOAA ship (Ronald H. Brown), and ground measurements. C-130 flight 6 encountered the strongest dust events.

Trajectory A

C-130 Flight 8

-0.04

-0.02

0

0.02

0.04

0.06

O3 B

ud

get

and

Its

Com

pon

ents

(p

pb

v/s)

FULLNORMALNODUST

1 0 x N et B u d g et

R #2

R #7

1 0 x R # 8

R # 1 7

1 0 x R # 2 3 7

R # 1 8

-0.04

-0.02

0

0.02

0.04

NO

2 B

udge

t an

d It

s C

ompo

nent

s (p

pbv/

s)

FULLNORMALNODUST

10 x N et B u d get

R #1

R # 7

10 x R #8

10 x R #9

10 x R #25

10 x R #31

10 x R #32

100 x R #236

-0.04

-0.02

0

0.02

0.04

NO

Bud

get

and

Its

Com

pone

nts

(ppb

v/s)

FULLNORMALNODUST

10 x N et B u d get

R #1

R #7

10 x R #9 10 x R #3 1

10 x R #51100 x R #21

-0.0002

-0.0001

0

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

OH

(pp

bv)

and

Its

Bud

get

Com

pone

nts

(ppb

v/s)

FULLNORMALNODUST

O H C o n cen tra tio n s

R #1 9

R #2 1

R #2 2

R #2 5R #2 9

R #3 0

R #3 1

1 0 x R # 4 1

R #4 4 R #1 2 5

Reaction # Reaction Equations

1 NO2 + hv NO + O3P

2 O3P + O2 O3

7 O3 + NO NO2 + O2

8 O3 + NO2 NO3 + O2

9 NO + NO3 2NO2

17 O3 + hv O2 + O3P

18 O3 + hv O2 + O1D

19 O1D + H2O 2OH

21 OH + NO HONO

22 HONO + hv OH + NO

25 OH + NO2 HNO3

29 OH + CO + O2 HO2 + CO2

30 OH + O3 HO2 + O2

31 HO2 + NO NO2 + OH

32 HO2 + NO2 HNO4

41 H2O2 + hv 2OH

44 OH + SO2 + H2O + O2 H2SO4 + HO2

125 OH + HCHO HO2 + CO

236 NO2 + Dust 0.5Nitrate + 0.5 Nitrite

237 O3 + Dust 1.5O2

Chemical budget when trajectory A passed over the polluted region, Beijing

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lia n D a y (G M T )

2 0

3 0

4 0

5 0

6 0

7 0

O3

(pp

bv)

0

1000

2000

3000

4000

AG

L (

m)

NORMALNODUSTFULLAltitude (AGL)Longitude

9 0

1 0 0

1 1 0

1 2 0

1 3 0

Lon

gitu

de

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5J u lia n D a y (G M T )

-0.002

-0.001

0

0.001

0.002

0.003

O3 B

ud

get

(pp

bv/

s)

-0.0002

-0.00016

-0.00012

-8E-005

-4E-005

0

O3 L

oss

on D

ust

(ppb

v/s)

NORMALNODUSTFULLO3 Loss on Dust

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lia n D a y (G M T )

0

2

4

6

NO

2 (p

pb

v)

-4E-005

-3E-005

-2E-005

-1E-005

0

NO

2 Los

s on

Dus

t (p

pbv/

s)NORMALNODUSTFULLNO2 Loss on Dust

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lia n D a y (G M T )

0

1

2

3

NO

(p

pb

v)

NORMAL NONODUST NOFULL NONORMAL: NO+O3 =>NODUST: NO+O3=>FULL: NO+O3=>

-0.04

-0.03

-0.02

-0.01

0

NO

Los

s vi

a [N

O+O

3=>N

O2+

O2]

(pp

bv/s

)

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lia n D a y (G M T )

0

2

4

6

8

10

SO2 (

pp

bv)

-8E-005

-6E-005

-4E-005

-2E-005

0

SO2 L

oss

on D

ust

(ppb

v/s)NORMAL

NODUSTFULLSO2 Loss on Dust

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lia n D a y (G M T )

0

0.004

0.008

0.012

HO

NO

/NO

2

NORMALNODUSTFULL

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lia n D a y (G M T )

0

1

2

3

NO

(pp

bv)

NORMAL NONODUST NOFULL NONORMAL: NO+O3 =>NODUST: NO+O3=>FULL: NO+O3=>

-0.04

-0.03

-0.02

-0.01

0

NO

Los

s vi

a [N

O+O

3=>N

O2+

O2]

(pp

bv/s

)

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lia n D a y (G M T )

0

2

4

6

8

10

SO2 (

pp

bv)

-8E-005

-6E-005

-4E-005

-2E-005

0

SO2 L

oss

on D

ust

(ppb

v/s)NORMAL

NODUSTFULLSO2 Loss on Dust

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lian D ay (G M T )

0

0.5

1

1.5

2

2.5

HN

O3

(pp

bv)

-0.00012

-8E-005

-4E-005

0

HN

O3

Het

erog

eneo

us

Los

s (p

pb

v/s)

NORMALNODUSTFULLHNO3 Budget in FULL

9 8 9 8 . 5 9 9 9 9 . 5 1 0 0 1 0 0 . 5 1 0 1 1 0 1 . 5Ju lian D ay (G M T )

0

4E-005

8E-005

0.00012

0.00016

0.0002

OH

(pp

bv)

NORMALNODUSTFULL

-0.0002 -0.00016 -0.00012 -8E-005 -4E-005 0O 3 L o s s o n D u s t (p p b v /s )

-25

-20

-15

-10

-5

0

O3 D

iffe

ren

ce (

FU

LL

-NO

RM

AL

) (p

pb

v)

Fit Line: Y = 108033 * X - 0.21 R2=0.87

The model simulations (FULL, NORMAL and NODUST) extracted along trajectory A (see map in left corner) show the impacts of dust heterogeneous and radiative processes on gaseous species and photochemistry. The main influence of dust heterogeneous reactions is reducing O3 concentration, which decreased NO2/NO ratio, but increased HONO concentration. During this journey, O3 difference was nearly linearly correlated with O3-Dust heterogeneous reactions, except over heavily polluted areas.

Trajectory A passed over the polluted area

Averaged Dust Radiative Impact on OH (%) below 1 km

Averaged Dust Radiative Impact on O3 (%) below 1 km

Averaged Dust Heterogeneous Impact (%) on O3 (left) and NO2 (right) below 1 km

Simulated dust influences below km averaged for April 4-14, 2001 show OH is mainly affected (up to 20% reduction) by dust reducing photolysis rates, which also results in O3 decrease in polluted areas and their downwind sites. In clean area, dut radiative influence tends to increase O3 by decreasing its photolytic loss. In average during this period, dust heterogeneous reactions have stronger impacts on O3 than its radiative influence. Regional O3 decrease due to heterogeneous reactions also affect other species, like NO2, through photochemical reactions.

Thank you for your attention

For further information, please check our papers:Tang, Y., et al. The impacts of dust on regional tropospheric chemistry during the ACE-Asia experiment: a model study with observations, J. Geophys. Res., doi: 10.1029/2003JD003806, in press, 2003.Tang, Y., et al. Three-dimensional studies of aerosol ions and their Size Distribution in East Asia during spring 2001, submitted to J. Geophys. Res..

Or contact us : Youhua Tang (ytang@cgrer.uiowa.edu) Greg Carmichael (gcarmich@engineering.uiowa.edu)

C-130 flight 6 encountered the strongest dust storm during ACE-Asia campaign, which strongly affected both aerosol (left) and gaseous (up) species via equalibria, heterogeneous and radiative processes.

•J. Geophys. Res.,