Ｄｕｓｔ Ｐａｒｔｉｃｌｅ Ｄｉｓｔｒｉｂｕｔｉｏｎ
ｉｎ Ｆｒｅｅ Ｔｒｏｐｏｓｐｈｅｒｅin 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)

Aircraft borne measurements in Japan(%)

025Spring mean
>4km

5Summer mean
>4km

5 650

1175

1008480-9%etcSea SaltSoil

Spring mean
<4km11

Summer mean
<4km35 6980

- 86 %

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 themean value for spring. Fractions by different particle types aresuperimposed. (Matsuki et al., JGR 2003)

Observations of Aerosols over
Taklamakan Desert• Observational Periods: 2001-2003• Aerosol concentration, size, morphology andchemistry• 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 coefficientof air molecules and aerosols, respectively.
Nonspherisity
Depolar. Ratio = P cross/P parallel
where P cross and P parallel are cross and parallel componentof backscattering powerVertical Profiles of Aerosols Measured
by Lidar at Dunhuang

Upper Boundary
AtAbout 6km

Large Depolarization Ratio
From near the boundary to about 6km

ExistenceofNonspherical Shape Particles

Clear Boundary at about 6km
InSpring and Summer

Characterizing Vertical Distribution of Aerosols
overDunhuang (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 Balloonborne impactor(JGR 2003 Iwasaka et al.)(this symposium M. Yamada et al.)Balloon-train

Positioning of sampler
is madeby GPS

Fine particles also were collected

(B)

(b)

(a)

(b)

(a)
C*
X-ray Counts

X-ray Counts

C*S

O*

0

1

23
4
5
6
X-ray Emission (keV)

Ni*

7O*

80

1

S

2

3
4
5
6
X-ray Emission (keV)

Ni*78

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

C*
X-ray counts(a)Typical electron micrograph of collected particles inspring in the range of 3-7km.
(a) Si-rich particle, (b) Ca-rich particle. The Ni* peak is dueto the Ni grid used inside the collection surface

O*
AlSiK

Ni*

5μm
01

2

3

Ni*
45678

X-ray emission (keV)(b)
X-ray counts

C*

10μm

CaO*Ni* Al Si
012

Ni*Ca
3456

X-ray emission (keV)

78Ｍｅａｓｕｒｅｍｅｎｔｓｏｆａｅｒｏｓｏｌ ｓｉｚｅ ａｎｄ ｃｏｎｃｅｎｔｒａｔｉｏｎ
ｗｉｔｈ ａｎ Ｏｐｔｉｃａｌ Ｐａｒｔｉｃｌｅ ｃｏｕｎｔｅｒshow
large decrease in concentration
ofparticles with all size ranges
near 5km

Particle concentration measured with aballoon borne OPC at Dunhuang
27August,2002>0.3μm
>0.5μm

10000>0.8μm
>1.2μm
>3.6μm(Y.S.Kim et al., JGR,2004)

Altitude, m

Coarse modeparticles well mixed
innear surface ~ 6km

8000

6000

4000

2000

00.0001

0.001

0.01

0.1

1

Number Conc. cm-3

10100

The trajectories of balloons
suggest noticeable westerly above about 5km
andsometimes north-easterly below about 5km

2003/3/24
9000m
7000m
5000m
3000m

6min
7min

48km
Launchingpoint
Landing
point

8min

2002/8/29
7972m
6852m

3min

5172m

5min

3179m 6min

Trajectories ofBalloon-borne sampler

launching

12km
landingWesterly becomes
clear
above about 5km

Combination of wind systemandgeographical situation
causes 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 insummer in the free troposphere• Above about 5-6km westerly dominates even in summer• Taklamakan desert can play as dust pool and source insummer• Long range transport of dust particles in summer isimportant from view point of radiative contribution ofparticles and chemistry on surface of dust
• In future systematic field studies of dust particles (weakKOSA) impact in summer season

Ｔｈａｎｋ Ｙｏｕ