SO2 observation at the summit of Mt. Fuji
Yasuhito Igarashi1, Yosuke Sawa1,Katsuhiro Yoshioka2, Hiroshi Takahashi3,Hidekazu Matsueda1, Yukiko Dokiya4
1Geochemical Research Department, Meteorological Research Institute,Ibaraki, Japan
2Shimane Prefectural Institute of Public Health and Environment Science,Shimane, Japan
3Atmospheric Environment and Applied Meteorology Research Department,
Meteorological Research Institute, Ibaraki, Japan
4Edogawa University, Chiba, Japan
Most of the content was recently published inIgarashi et al., Atmos. Environ., 40 (2006) 7018‒7033

Photo fromwww2.ocn.ne.jp/~ynika57

Advantage of Mt. Fuji
Comparison with other mountain platform foratmospheric chemistry (EW cross section)（Original drawing was depicted by Kashmir, a PC software ）Introduction• SO2 is a precursor of sulfate which has impacts on theacidification and climate change.
• Concerned is the Asian outflow of the pollution overthe Pacific region. e.g. aircraft observation such as
ACE-Asia, PEM-West, TRACE-P, etc.
• Little SO2 observation at mountain sites situated in
the free tropospheric condition especially in the farEast• SO2 observation using a UV fluorescence monitor was
carried out during Sep. 2002 to Jul. 2004 at thesummit of Mt. Fuji.
• Today’s talk highlights high SO2 episodes and its
seasonal change.

・ Global emission inventory of gaseous S(average of 11 models referred in IPCC 2001)
98.2±14.7 TgS/y・ SO2 emission inventory from Asia （2000）

17.2 TgS/y

D.G. Streets etal., JGR, 2003.
Mt. Usuzan Mt. Tokachidake

Grid： 30min×30min
Unit： Mg/y

Mt. Asama-yama
Mt. FujiKuju Group
Mt. Oyama,Miyake-jima
Mt. Aso Mt. Kirishima-yamaisland
Mt. Satsuma-Iojima Mt. Sakura-jima
Mt. Suwanose-jima・SO2 emission from active volcano(quiescent condition) in Japan :0.55 TgS/y (Fujita et al., 1992)
・Anthropogenic emission in Japan :0.4 TgS/ySO2 emission from the Miyake-jima island
ton/day

ton/day

2000 average: 42 kt/day= 7.7 TgS/year
Below 10 kt/day= Below 1.8 TgS/year

Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug Dec Apr Aug

2000

2001

2002

2003

2004

2005

From JMA Reports on Volcanic Activity in JapanTemporal variation of SO2 concentration during winter months(Oct. 2002 - Feb. 2003)
Y. Igarashi et al., J. Geophys. Res., 109, D17304,doi:10.1029/2003JD004428.

Hourly median

Basically no diurnal changeLowa) BG contrasted with high SO2 episodes
Significant during winter months

86
4
2045

NNW36

W

27

SSW

18

SE

9ENE
N

0
Oct/06/02

Oct/26/02

Nov/15/02

Dec/05/02

Dec/25/02

Jan/14/03

Feb/03/03

Feb/23/03

Wind direction

Wind speed (m/s)

2Concentration of SO (ppbv)

10Temporal variation of SO2 concentration during summer months(Jun. 2003 - Oct. 2003)
Y. Igarashi et al., J. Geophys. Res., 109, D17304,doi:10.1029/2003JD004428.

Hourly median864

Almost no highSOb)2 episodes
during summermonths

Max 14ppbv

Only one case of apparent
direct signal of theMiyake-jima plume

2045

NNW36

W

27

SSW

18

SE

9ENE

0
May/28/03

N
Jun/17/03

Jul/7/03

Jul/27/03

Aug/16/03

Sep/5/03

Sep/25/03

Oct/15/03

Nov/4/03

Wind direction

Wind speed(m/s)

2Concentration of SO (ppbv)

10Temporal variation of SO2 concentration
during winter to summer: shift seasonal
WhatNoisapparentthe cause
theMiyake-jimachange?plume！
effectofof the・Seasonal change in source
Hourly medianmax. 6.45ppbv
・Seasonal change of air mass・Whateverscavenging including oxidation during
SO2 episodes were significant
the transport during winter！

7

SO2 concentration (ppbv)

65

Frequency and intensity
decrease in late April toearly May

43
2
10-1
Jan.

Feb.

Mar.

Apr.

Date in 2004

MayJun.

Jul.

Comparison of temporal change in SO2 concentration
with those of 222Rn and CO (Feb. 2004 – May 2004)

500
CO
ratherthanSO
shouldhaveshownseasonalchange.
222CO concn.
6Rn concn.2
SO BG concn
2400

5300
42003100
2010Feb

From Streets et al., JGR, 2003
MarAprMay

CO concn. (ppbv)

Rn concn. (Bq/m3) SO2 concn. (ppbv)• Good correlations in general among these gases• Concentration decrease in SO2 and radon after spring• Basically little change in CO
Seasonal change in SO2• Transport episode exists even in May
emission?

Temporal variation in wind and RH on site
(Jan. 2004 - Jul. 2004)

Relative humidity (%)

Shift in prevailing windWind dir.

NNW40W30SSWWNWNW

WSW

20SE

10ENE

0100

N80604020RH(%)
0JanFebMar

Apr

Date in 2004

MayJunJulWind direction

Wind speed (m/s)

50Wind speed

Backward trajectory Apr/01-Apr/10

Change in backward
trajectories from thesummit of Mt. Fuji
during Apr. 2004 toMay 2004
Backward trajectory May/21-May/31

Backward trajectories from the SW sector increased in May
Calculated by HYSPLIT model, NOAA

Seasonal change of RH in the air mass reaching tothe summit of Mt. Fuji
250

250

RH≥65: 19.5%

50150

100

10 20 30 40 50 60 70 80 90 100

1501005000RH≥65: 35.2%

RH≥65: 29.9%

50

0200

Frequency

100200Frequency

150MayApril

200

Frequency

Frequency

RH≥65: 17.9%

250

MarchFebruary

200

250

0010 20 30 40 50 60 70 80 90 100 110

010 20 30 40 50 60 70 80 90 100

Relative humidity (%)

Relative humidity (%)

100

500-10150

0

10 20 30 40 50 60 70 80 90 100

Relative humidity (%)

Relative humidity (%)

Seasonal change of maximal RH in the air massreaching to the summit of Mt. Fuji
FebruaryFrequency

424

1020304050 60

7080

Relative humidity (%)

90 100 110

RH≥90: 30%

642000102030

40

50 60

7080

Relative humidity (%)

90 100

May8RH≥90: 41%

620April

8RH≥90: 32%

610March8

RH≥90: 21%
Frequency

10Frequency

810Frequency

1064200102030

40

50 60

7080

Relative humidity (%)

90 10000102030

40

50 60

7080

90 100Relative humidity (%)(2004)

Relative humidity (%)

500
222

6Rn concn.
SO concn.
2CO concn.

5400
300

4200
3100
201

CO concn. (ppbv)

222

Rn concn. (Bq/m3)
SO2 concn. (ppbv)

Case studies of transport episodes appeared in SO2, COand 222Rn time series during Apr. 2004 to May 2004

01008060
40200Mar/31

RH(%)
Apr/6

Apr/12

Apr/18Apr/24

Apr/30

May/6

Date in 2004

Apr. 16/17
SO2 CO and 222Rn increased together

May/12

May/18

May/24

May/30

May 5, no increase found for SO2
while 222Rn and CO increased

Comparison of two episodes by the backward
trajectory analysis

100

100

8080

RH(%)

RH(%)

Possibly cloudprocesses

6040200A p r/1 7604020A p r/1 5

A p r/1 3

A p r/1 1

A p r /9

A p r/7

D a teRH was at the moderate level.

A p r/50
M a y/06

M ay/04

M a y /0 2

A p r/30

D a teRH was high.

A p r/2 8

A p r/2 6

A p r/

Summary and Future tasks• SO2 climatology was revealed at first time.
• The high SO2 concentration episode in winter was noteworthyand quite sporadic.
• SO2was transported coincidently with CO and 222Rn,confirming Asian continental pollution transport.
• Backward trajectory analysis also indicated the continentalorigin of such episodes.
• The SO2 episode reduced its frequency and intensity around
April to early May. Most likely causes are air mass change
and related change of RH (encounter possibility with clouds)• Impacts of the Miyake-jima SO2 were in general small as theplume height was not so elevated as entering into the freetroposphere since late of 2002.
• SO2 undergoes into sulfate. What is the fate of sulfate during
the transport? Is there seasonal change? Simultaneous
measurements of SO2 and sulfate with similar time resolution
should be done in the future.