12 June 2012
2012 ACCENT-IGAC-GEIA Conference
Recent changes in anthropogenic
emissions in Asia:
REAS 2.0 inventory and inverse modeling
Toshimasa Ohara
National Institute for Environmental Studies (NIES), Japan
Jun-ichi Kurokawa
Asian Research Center for Air Pollution (ACAP), Japan
Itsushi Uno
Research Institute for Applied Mechanics, Kyushu University, Japan
W-Europe
USA
Global NO2 distribution from space
Granier et al.
(2011)
India
Burrows et al. (2007)
China
Background and aims
(1)  The rapid growth in many Asian countries in recent
years led to the significant increase of urban,
regional, and trans-boundary air pollution.
(2)  An understanding of long-term and future changes
for Asian emissions is an area of increasing
scientific interest and political concern.
(3)  The aims of this work are;
(a) to understand the recent trends of
anthropogenic emissions in Asia
* We updated the REAS v.1 to the REAS 2.0.
(b) to verify and improve the emission
inventories based on the inverse modeling
3
Limitation of REAS v.1
・Latest year of historical emissions and the base
year of projected emissions become older.
→ Energy consumption in Asia is growing
continuously.
・Recent changes of EFs due to emission control
were not taken into account.
→ Ex. FGD for coal-fired power plants.
・Request from recent simulation models:
- Fine spatial resolution
- Seasonal variation
- Expansion of model domain and species
4
Outline of REAS 2.0
Item
Descrip+on
Target Areas
E, SE, and S Asia + Russian & Central Asia
Target Years
2000-­‐2008 (→ 2010)
Spa+al Resolu+on
0.25 x 0.25 degree
Temporal Resolu+on Monthly
* Japan
JATOP inventory
* Korea and Taiwan
Official report
SO2 NOx CO PM10 PM2.5 BC
OC
Fossil Fuel Biofuel
● ●
●
●
●
●
●
●
●
Industrial Process
●
●
●
●
●
●
●
●
Fer+lizer use
NMV NH3 CH4 N2O CO2
●
Livestock
Others
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
5
Spatial distributions of annual emissions in 2008 NOx
SO2
BC
NMVOC
NH3
CH4
(NOx, SO2,NMVOC)
(NH3)
(BC)
(CH4)
0
0
0
0
0.8
0.4
0.1
1.0
1.6
0.8
0.2
2.0
2.4
1.2
0.3
3.0
3.2
1.6
0.4
4.0
4.0 (Kt yr-1grid-1)
2.0
0.5
6
5.0
Changes of NOx emissions from 2000 to 2008 Regional %
Sectoral %
2000
2008
Main contributing countries:
China (50%), India (20%)
Change of contribution:
China (+), Other E Asia (-)
Main contributing sectors:
PP, Industry, Road
Change of contribution:
PP(+), IND(+), Others (-) 7
Temporal variation of annual emissions in Asia [Mt]
NOx
・ Asian NOx emissions were increased by 50 %.
・ China’s NOx was more than doubled, but increase
rate becomes smaller recently.
・ NOx in SE Asia and India also increased rapidly (65%
and 40%, respectively) due to the increase of energy
consumption in power plants and road transport .
[Mt]
SO2
・ Asian SO2 emissions were increased by 35 %.
However, that were decreased after 2006.
・ The contribution of power plants was decreased
after 2004.
・ India’s SO2 were still increasing rapidly (50%).
8
Temporal variation of annual emissions in Asia [Mt]
BC
・Asian BC emissions were increased by 30 %.
・Domestic sector is the largest and industry is the
second.
・Domestic % went down due to the decrease of coal and
biofuel consumption.
[Mt]
NMVOC
・ Asian VOC emissions were increased by 44%,
・ Sectoral % in Asia increased in solvent and paint
use while it decreased in domestic sector.
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Temporal variation of annual emissions in Asia [Mt]
CH4
・Asian CH4 emissions were increased by 32%.
・Sectoral % is varied by region. (China: Coal mining,
India: agriculture, Others: fugitive and rice field)
・The contribution of fugitive emissions is increasing.
[Mt]
NH3
・Asian NH3 emissions were increased by 18%.
・Fertilizer applications are the most dominant, and
second is manure management of livestock.
・Sectoral % is almost constant during the period.
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Temporal variation of monthly NOx emissions in Asia 1400
1200
Power P.
Road
Domestic
Total
6000
Industry
Other trans.
Soil
5000
Total NOx (kt month-­‐1)
Sectoral NOx (kt month-1)
1600
4000
1000
800
3000
600
2000
400
1000
200
0
200001
0
200101
January, 2008
200201
200301
200401
200501
Year/month
200601
August, 2008
200701
200801
Total NOx emission shows a mixed
temporal variation of increasing trend
and distinct seasonality with summer
maximum and winter minimum.
The seasonal variation is caused by
the soil NOx, which seems to be
exaggerated in seasonality and/or
be overestimated in emission
amounts. It should be verified by some
measurements. (t month-1grid-1)
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NOx and BC in China during 1980-2010
NOx
[Mt]
30 REAS 1.1
REAS 2.0
Zhang et al. (2007), INTEX-­‐B
Hao et al.
The emission levels from
each estimates are slightly
different. But, their interannual variations are very
similar.
Increase -> level-off ->
projection rapid increase -> slowdown
GAINS
20 10 0 1980
3.0 BC
[Mt] 2.5 1985
1990
REAS 1.1
Zhang et al. (2007), INTEX-­‐B
Qin & Xie (2012)
Fu et al. (2012)
1995
REAS 2.0
Lu et al. (2011)
Kondo et al.(2011)
2000
2005
2010
We failed to predict the
emissions for 2010 due to
under-prediction of coal
consumption in China.
The inter-annual variations from
each bottom-up inventory are
relatively similar.
Top-down
2.0 For the emission amounts, there
are a gap between bottom-up
inventories and a big gap
between top-down and bottomup estimations.
1.5 1.0 0.5 0.0 1980
1985
1990
1995
2000
2005
2010
The uncertainty in BC is still
large.
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Recent trends of NOx emissions in East Asia
REAS vs. Inverse model Inverse model based
on CMAQ and satellite
NO2 VCD
CMAQ (Byun and Schere,2006) Comparison between simulated and observed NO2 VCDs over each grid and calcula+on of emission adjustment factors
n = 6 ?
No
n = n + 1
Updated emissions by emission adjustment factor 2.5 China
Consistent with bottom-up
estimates, but the trend of
REAS is steeper .
2.0 Ini+al condi+on
Yes
Observa+on GOME/ SCIAMACHY NO2 VCDs Met. Fields RAMS (Pielke et al.,1992) (in offline manner)
Final Top-­‐down emissions
Ratio to emissions for 2000
A priori emissions
1.5 1.0 Inversion
REAS 2.0
0.5 0.0 1996
1.4 1998
2000
2002
2004
REAS 1.1
INTEX-­‐B
2006
2008
Completely consistent with
REAS except for 2003
Japan
Inversion
1.2 REAS 1.1
REAS 2.0
1.0 0.8 0.6 0.4 1996
13
1998
2000
2002
2004
2006
2008
13
Seasonal and weekly variations of NOx
emissions in Japan
Ratio to averaged monthly
emissions
Seasonal variation
2.0 Inversion
1.5 1.0 0.5 0.0 Weekly cycle
(Tokyo)
REAS
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Satellite NO2 VCD
（●）
NOx emission inventory（●）
Surface observed NOx （●）
Weekly cycle is similar between
three different data sources. 14
Summary
l  We have updated the regional emission inventory in Asia
(REAS v1) to the REAS 2.0 and verified it by top-down
approach. The REAS 2.0 covers the anthropogenic emission
sources in Asia during 2000-2008 (or 2010) .
l  Asian emissions for all species (except SO2) show
increasing trend during 2000 and 2008.
l  The contributions from China are the largest in Asian
emissions. However, the growth of China’s emissions are
slowing down due to a series of reinforcement of emission
control.
l  Relative importance of emissions from Southeast, India,
Russian and Central Asia is increasing.
l  REAS 2.0 will be opened on the website, soon.
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