Ｄｕｓｔ Ｐａｒｔｉｃｌｅ Ｄｉｓｔｒｉｂｕｔｉｏｎｉｎ Ｆｒｅｅ Ｔｒｏｐｏｓｐｈｅｒｅ

in East Asia and West Pacific Ocean

Ｙ．Ｉｗａｓａｋａ （ＮＵ), Ｇ．－Ｙ．Ｓｈｉ （ＩＡＰ）Ｚ．Ｚｈｅｎ （ＣＡＲＥＥＲＩ）, Ｙ．Ｓ．Ｋｉｍ （ＨＵ/NU）Ａ．Ｍａｔｓｕｋｉ（ＮＵ），Ｄ．Ｔｒｏｃｈｋｉｎｅ（ＩＷＥＰ/NU）

M.Yamada(NU), T.Nagatani(NU)D.Zhang(PUK), T.Shibata(NU)

Observed seasonal change in the vertical structure of coarse (D＞1µm) aerosols over Japan. Relative seasonal change in the total number of coarse particles is shown as 100% being the mean value for spring. Fractions by different particle types aresuperimposed. (Matsuki et al., JGR 2003)

5

5

11

3

6

9

5

84

80

80

6

11

0 25 50 75 100

Spring mean >4km

Summer mean>4km

Spring mean <4km

Summer mean<4km

(%)

etcSea SaltSoil

- 86 %

- 9 %

Aircraft borne measurements in Japan

Observations of Aerosols over Taklamakan Desert

• Observational Periods: 2001-2003• Aerosol concentration, size, morphology and

chemistry

• Lidar• Balloon-borne Optical Particle Counter• Electron-microscopic experiments of particles

collected directly in free troposphere over Taklamakan desert

Ｌｉｄａｒ Ｍｅａｓｕｒｅｍｅｎｔｓ

Ａｅｒｏｓｏｌ Ｃｏｎｃｅｎｔｒａｔｉｏｎ

Ｓｃａｔｔ． Ｒａｔｉｏ ＝ [Ｂ１ ＋ Ｂ２]/B1

Where B1 and B2 are backscattering coefficient of air molecules and aerosols, respectively.

Nonspherisity

Depolar. Ratio = P cross/P parallelwhere P cross and P parallel are cross and parallel component

of backscattering power

Vertical Profiles of Aerosols Measured by Lidar at Dunhuang

Upper BoundaryAt

About 6km

Large Depolarization RatioFrom near the boundary to about 6km

Existence of

Nonspherical Shape Particles

Clear Boundary at about 6kmIn

Spring and Summer

Characterizing Vertical Distribution of Aerosols over

Dunhuang (possibly Taklamakan Desert)

Existence of Mineral Particles deduced from electron-microscopic experiments of particles collected

over Dunhuang

• summer of 2002 and spring of 2003• Collection of particulate matter with a Balloon-

borne impactor(JGR 2003 Iwasaka et al.)(this symposium M. Yamada et al.)

Balloon-train

Positioning of sampleris madeby GPS

0 1 2 3 4 5 6 7 8

X-ray Emission (keV)

X-ra

y C

ounts

C*

O*Ni*

S

0 1 2 3 4 5 6 7 8

X-ray Emission (keV)

X-ra

y C

ounts

C*

O* SNi*

(a) (b)

(b)

(a)

(B)Fine particles also were collected

Electron micrograph of individual particles collected in the free troposphere between about 3km and 5km over Dunhuang, China.Both fine particles (a) and (b) are ammonium sulfate.

Typical electron micrograph of collected particles in spring in the range of 3-7km.

(a) Si-rich particle, (b) Ca-rich particle. The Ni* peak is due to the Ni grid used inside the collection surface

5μm

10μm

0 1 2 3 4 5 6 7 8

X-ra

y co

unts

X-ray emission (keV)

C*

SiAl

O*

K Ni*Ni*

(a)

(b)

0 1 2 3 4 5 6 7 8

X-ra

y co

unts

X-ray emission (keV)

C*

O*

Si Ni*

Ca

Ni* Al Ca

Ｍｅａｓｕｒｅｍｅｎｔｓｏｆ

ａｅｒｏｓｏｌ ｓｉｚｅ ａｎｄ ｃｏｎｃｅｎｔｒａｔｉｏｎｗｉｔｈ ａｎ Ｏｐｔｉｃａｌ Ｐａｒｔｉｃｌｅ ｃｏｕｎｔｅｒ

show large decrease in concentration

of particles with all size ranges

near 5km

Particle concentration measured with a balloon borne OPC at Dunhuang

27August,2002

0

2000

4000

6000

8000

10000

0.0001 0.001 0.01 0.1 1 10 100

Number Conc. cm-3

Altit

ude,

m

>0.3μm

>0.5μm

>0.8μm

>1.2μm

>3.6μm

Coarse mode particles well mixed

in near surface ~ 6km

(Y.S.Kim et al., JGR,2004)

The trajectories of balloons suggest noticeable westerly above about 5km

andsometimes north-easterly below about 5km

12km

launching

landing6min

5min

3min

3179m

5172m

6852m7972m

48kmLaunchingpoint

Landingpoint8min

7min

6min

3000m

5000m

7000m

9000m

2002/8/29

2003/3/24

Trajectories of Balloon-borne sampler

Westerly becomes clear

above about 5km

Combination of wind system and

geographical situationcauses outflow of particles even in summer above 5km

According to Sun et al.north-easterly dominates

near surface

Summary

• Coarse dust particles were frequently observed in summer in the free troposphere

• Above about 5-6km westerly dominates even in summer

• Taklamakan desert can play as dust pool and source in summer

• Long range transport of dust particles in summer is important from view point of radiative contribution of particles and chemistry on surface of dust

• In future systematic field studies of dust particles (weak KOSA) impact in summer season

Ｔｈａｎｋ Ｙｏｕ