Transcript Document

What have we
Learned from
ACE-Asia?
The ACE-Asia Science Team
Tim Bates (NOAA PMEL),
Phil Russell (NASA Ames), and
Barry J. Huebert
Department of Oceanography
University of Hawaii
Honolulu, HI 96822 USA
[email protected]
B.Huebert, ACE-Asia, 03/03
Characterization: Determine the physical,
chemical, and optical properties of the major aerosol
types in the Eastern Asian and Northwest Pacific
region and investigate the relationships between
these properties.
1. How do the aerosol chemical, physical, and optical
properties change with altitude, location, and time in
Asia?
2. How absorbing are Asian dust and pollution aerosols?
3. How do the size and light scattering by Asian aerosols
change with relative humidity?
B.Huebert, ACE-Asia, 03/03
Radiation: Quantify the interactions between
aerosols and radiation in this region.
4. With what accuracy can in situ measurements be
integrated over the depth of the atmosphere to predict
the observed radiative effects?
5. How much quantitative information about aerosols and
their radiative impacts can be derived from satellites and
other remote sensors?
6. What is the radiative forcing by Asian aerosols and how
does it change with emissions, time, and distance from
the continent?
B.Huebert, ACE-Asia, 03/03
Processes: Quantify the physical and chemical
processes controlling the evolution of the major
aerosol types and of their physical, chemical, and
optical properties and incorporate these into
improved models.
7. Are the available source inventories for Asian primary
aerosols and gas-phase precursors sufficiently realistic
to support assessments of control strategies?
8. How are aerosol properties and dynamics modified by the
uptake of gases?
B.Huebert, ACE-Asia, 03/03
1. How do aerosol chemical, physical, and optical properties change
with altitude, location, and time in Asia?
Dust acts like a sponge, soaking up pollutant gases
and aerosols.
These SEM micrographs by Jim Anderson (ASU) show
the way soot balls (pollution) coat mineral dust particles
Many different forms of soot stuck
on a particle of quartz (SiO2).
Complex aggregate of soot, mineral
particles (upper), and a non-soot particle.
B.Huebert, ACE-Asia, 03/03
Toxic metals become attached to dust even quite close to
dust sources (data from Zhenbeitai, PRC)
10
Crustal Elements are not
Enriched in ZBT Aerosols
0
10
Ca
0
But Pollution Elements ARE
Enriched in ZBT Aerosols
Fe
Mg
K
Na
-1
10
Aerosol Ratio Element / Al
Aerosol Ratio Element / Al
10
Ti
10
Mn
Ba
-2
Sr
10
Ce
Co
Li
La
Sc
Nd
-3
-1
Pb
10
-2
Zn
Cr
V
Cu
Ni
10
-3
10
-4
10
-5
Tl Sb
Mo
Cd
Th
10
Pr
Gd
Sm
Dy
U
Er
-4
Eu
10
Data f rom R Arimoto and XY Zhang
-5
10
-5
10
-4
10
-3
10
-2
10
-1
Crustal Reference Ratio Element / Al
10
0
Data f rom R Arimoto and XY Zhang
10
-5
10
-4
10
-3
10
-2
10
-1
Crustal Reference Ratio Element / Al
10
0
Arimoto, Zhang, Kang, Huebert, Savoie, Prospero, Sage, Schloesslin, and Khaing, Chemical composition
of aerosols from Zhenbeitai, People's Replublic of China and Gosan, South Korea observed during ACEAsia, J. Geophys. Res., in prep (ACE-Asia Special Issue B), 2003.
B.Huebert, ACE-Asia, 03/03
SO2 and Scattering
Profiles
D
Total Scattering <10um
SO2_1_sec_pptv
Submicron Scattering
5000
D
Not all layers are the
same: some dust
layers are more
modified by pollution
than others.
C-130 sounding over Yellow Sea
4000
Blue = Total Scatt
Green= <1um Scatt
Red = SO2
D
3000
D
P
2000
P
SO2 and dust co-exist
from 4-5 km, but dust has
scavenged all SO2 from
the 3-4 km layer.
1000
P
0
Courtesy of Blomquist, UH; Bandy, Drexel;
Masonis & Anderson, U. Washington
B. Huebert, ACE-Asia, 03/03
10
20
30
40
50
60
70
80
XTSG10
0
1000
10
2000
SO2_1_sec_pptv
20
30
3000
40
XTSG1
4000
50
60
2. How absorbing are Asian dust and pollution aerosols?
Light absorbed by aerosols is highly variable
regionally. Unpolluted Asian dust does not absorb
much as we expected.
Co-Albedo (Absorption)
0.20
1
2
3
Fine_Only____All_Aerosols____Coarse_Only
0.15
Replotted by BJH
Co-albedo is the
fraction of light
extinction due to
absorption. (The
balance is
scattering.)
0.10
0.05
0.00
Asian Fine Polln
Indian Ocean
N America
PollutedDust
1 km Dust
6 km Dust
Courtesy P. Quinn (NOAA-PMEL) and S. Masonis (UW)
The perception of how much light dust absorbs is changing rapidly!
Anderson, Masonis, Covert, Ahlquist, Howell, Clarke, and McNaughton, Variability of aerosol optical
properties derived from in-situ aircraft measurements during ACE-Asia, J. Geophys. Res., Submitted (ACEAsia Special Issue), 2003.
B.Huebert, ACE-Asia, 03/03
The Mass Absorption
Efficiency of soot is
controversial.
Ron Brown data argues that
MAE ~ 9 m2/g for PM-10
Their MAE ~ 12 m2/g for PM-1
With Mie theory it is hard to
explain MAEs larger than about
10 m2/g
Quinn, Bates, Coffman, Miller, Covert, and Welton, Marine boundary layer aerosol optical properties during
ACE Asia as a function of aerosol source region, J. Geophys. Res., ACE-Asia Special Issue B, 2003.
B.Huebert, ACE-Asia, 03/03
By contrast, BC encountered by the C-130 often had a Mass
Absorption Efficiency (MAE) less than 10 m2/g.
Absorption 532, Mm-1 (S/N>2)
20
MAE=5
MAE=10
15
MAE=2 m2/g
10
5
Dusty samples
Scattering dominated by pollution
0
0
1
2
3
EC, ug/sm3 (S/N>2)
4
5
6
Bertram, Huebert, Howell, Eatough, Masonis, Anderson, Blomquist, and Heath, Organic and elemental
carbon vs altitude during ACE-Asia, J. Geophys. Res., in prep, 2003.
B.Huebert, ACE-Asia, 03/03
MAE, m2/g
When we sort the C-130 MAE to eliminate high-dust cases,
the remaining data shows the clear impact that coating
materials (OC and NSS) have on the MAE of soot
(OC+NSS)/EC
Bertram, Huebert, Howell, Eatough, Masonis, Anderson, Blomquist, and Heath, Organic and elemental
carbon vs altitude during ACE-Asia, J. Geophys. Res., in prep, 2003.
B.Huebert, ACE-Asia, 03/03
3. How do the size and light scattering by Asian aerosols
change with relative humidity?
Aerosol Optical Properties Show Broad Diversity with Aerosol Type
Controlled RH Nephelometry showed that hysteresis plays a large role.
3
sp dry (1/Mm)
200
2
0
f(RH)
marine
dust
anthro
1
0.5
å
1
0
Marine Period
Dusty Period
Anthropogenic Period
-0.5
marine
dust
anthro
0
0
20
40
RH (%)
60
80
100
Carrico, Kus, Rood, Quinn, and Bates, Mixtures of pollution, dust, seasalt and volcanic aerosol
during ACE-Asia: Aerosol radiative properties as a function of relative humidity, J. Geophys. Res.,
Submitted (ACE-Asia Special Issue), 2003.
B.Huebert, ACE-Asia, 03/03
How do the size and light scattering by Asian aerosols change
with relative humidity?
This is also controversial, since the surface and the airborne
measurements give different values.
The table below is from four fly-by comparisons:
Ratio C-130/Ron Brown
5-Apr-05
9-Apr-05
13-Apr-01
17-Apr-01
EXTENSIVE PARAMETERS: C-130 R Brn ratio C-130 R Brn ratio C-130 R Brn ratio C-130 R Brn ratio
ambient RH 53
56 0.94
83
93
0.89 46
52 0.90 55
69 0.80
Total 550 Scatt, amb RH
58
52
1.11
168
275
0.61
127
103
1.24
50
50
1.00
Total abs, 550nm:
4.6
7.3
0.63
15.9
8.6
1.84 11.8
9.0
1.31
7.6
7.1
1.08
1.85 2.28*
1.79
2.34
1.48
1.84
1.78
2.43
0.91
0.85
0.92
0.90
0.92
0.85
0.88
INTENSIVE PARAMETERS:
Total f(RH), 40-85%RH
Total SSA
0.88
LEGEND:
= C-130 parameter is larger
= R. Brn parameter is larger
= two values are equal!
Courtesy Sarah Masonis et al.
B.Huebert, ACE-Asia, 03/03
4. With what accuracy can in situ measurements be integrated over
the depth of the atmosphere to predict the observed radiative
effects?
Sun photometer extinction was modeled from Twin Otter composition and
size data. The results were good except when large particles (dust or sea
1 2 3 45x10
salt) were present.
(cm )
3
-3
o
( C)
0
15
=525 nm
=1059 nm
3
The C-130 LTI-derived
size and composition
data does not have this
coarse particle
disagreement, perhaps
due to the LTI inlet
(Redemann et al., 2003).
3.0x10
Altitude (m)
2.5
RH
T
N
Predicted
AATS-14
AATS-14
(averaged)
2.0
1.5
1.0
0.5
0.0
20 40 60 800
RH (%)
0.1
0.2
0
0.05 0.10 0.15
A erosol Extinction (1/km)
Schmid, Hegg, Wang, Bates, Redemann, Russell, Livingston, Jonsson, Welton, Seinfeld, Flagan, Covert,
Dubovik, and Jefferson, Column closure studies of lower tropospheric aerosol and water vapor during ACE-Asia
using airborne sunphotometer, airborne in-situ and ship-based lidar measurements, J. Geophys. Res., submitted
(ACE-Asia Special Issue), 2003.
B.Huebert, ACE-Asia, 03/03
Radiation column closure has been used to infer 0 and 
550 (or SSA) ≈ 0.90-0.95 near surface, 0.95-0.98 (less absorbing) aloft
 (wavelength dependence) is larger for pollution than dust
Elevated layers
of coarse dust
Fine pollution
aerosols near
the surface
B.Huebert, ACE-Asia, 12/02
Huebert, ACE-Asia, 03/03
5. How much quantitative information about aerosols and their
radiative impacts can be derived from satellites and other remote
sensors?
We have a rich data set of in
situ profiles in satellite scenes
Coordinated
Twin
C-130
Flights
Otter
MODIS
9
6
MISR
6
4
MISR/LM
3
unk
SeaWiFS
7
8
NOAA-14
2
2
NOAA-16
4
B.Huebert, ACE-Asia, 03/03
AOD is often derived from satellites
How good is this retrieval?
B.Huebert, ACE-Asia, 03/03
Comparison of the SeaWiFS algorithm with airborne Sun
Photometer data suggests there is room for improvement…
Courtesy Schmid, Hsu et al.
Many more satellite studies are underway…
B.Huebert, ACE-Asia, 03/03
B.Huebert, ACE-Asia, 03/03
Lidar remote sensing
During a period in which the
C-130 flew as close as
possible to the Tokyo-area
lidars, remarkable
agreement was found
between the TUMM Lidar, in
situ extinction (PSAP &
Nephelometer), and the
AATS-6 Sun Photometer.
Disagreement in the BL may
be due to spatial variability in
the metropolitan area.
Murayama, et al., An intercomparison of
lidar-derived aerosol optical properties with
airborne measurements near Tokyo during
ACE-Asia, JGR, 2003. B.Huebert, ACE-Asia, 03/03
6. What is the radiative forcing by Asian aerosols and how does it change with
emissions, time, and distance from the continent?
Combining the SeaWiFS data and ACE-Asia in situ aerosol optical
properties allows us to estimate the direct surface aerosol forcing:
about -30 w/m2, large and negative (cooling)
B.Huebert, ACE-Asia, 03/03
“… monthly mean…aerosol direct effect… from
a satellite method -2 to -4 W/m2 at TOA
and -20 to -70 W/m2 at surface, … large
regional difference caused by…AOT and
SSA.
“However … direct forcing … strongly depends
on the estimation method of the aerosol
properties, especially on the SSA.
SPRINTARS aerosol model generates SSA
values larger by 0.1 than surface-measured
values, so that the modeled direct forcing
at surface ranges from -3 to -10 W/m2
which are significantly smaller than
those from satellite method.
“…aerosol indirect effect is estimated from
satellite method and SPRINTARS model as
-1 to -3 W/m2 at both TOA and surface.”
Nakajima, T., and APEX Science Team, Significance
of direct and indirect radiative forcings of
aerosols in the East Asian region, JGR, 2003.
B.Huebert, ACE-Asia, 03/03
From radiative flux measurements at Gosan:
“The diurnal forcing efficiency was determined to be –73.1, -36.3,
and – 41.7 Wm-2/500 for the total solar, near-infrared, and visible
spectral regions.”
“… a larger percentage of
the flux at visible
wavelengths is radiatively
forced compared to the
total and near-infrared
portions of the solar
spectrum.”
Bush and Valero, Aerosol Radiative Forcing at Gosan during the ACE-Asia campaign, J. Geophys.
Res., submitted (ACE-Asia Special Issue), 2003.
B.Huebert, ACE-Asia, 03/03
7. Are the available source inventories for Asian primary aerosols and
gas-phase precursors sufficiently realistic to support assessments of
control strategies?
Our Observations of Asian Dust Have Already Improved
Emissions inventories in models
We Found More Than 1000 µg/m3 of Dust in
the Yellow Sea.
SeaWiFS Courtesy NASA and Orbimage
Models had not included a drought-stricken region in Liaoning Province, which can now be a
source of dust to Korea and Japan
B.Huebert, ACE-Asia, 03/03
BC Modeling issues
“… it appears that the emission estimates of BC are qualitatively correct.
“… emissions from Japan may be underestimated
“… under predicting BC levels at low altitudes in the Yellow Sea [Carmichael
et al., 2002].
“… reported BC values are very dependent on the analysis method.
“… how best to use the surface data in the constraint of BC emission
estimates.
“… much of the flux of BC occurs at altitudes well above the surface layer.
“… we do not have sufficient information upon which to constrain wet and dry
removal fluxes of BC.”
Uno, Carmichael, Street, Satake, Takemura, Woo, Uematsu, and Ohta, Analysis of surface black
carbon distributions during ACE-Asia using a regional scale aerosol model, J. Geophys. Res., in
press (ACE-Asia Special Issue), 2003.
B.Huebert, ACE-Asia, 03/03
Table 2. Estimated total emissions for April 2001 in East Asia.
Ê
Anthropogenic
(Gg/Yr)
Biomass
Burning
(Gg/Yr)
Total (Gg/Yr)
Uncertainty
± (%)
SO2
2701
55
2756
16
NOx
CO
NMVOC
1863
17369
3309
407
10053
1791
2270
27422
5100
37
185
130
CH4
8377
460
8838
65
NH3
2186
136
2323
72
CO2
BC
OC
Wind BlownDust
709
166
578
167
67
498
877
233
1076
240,000-650,000
31
360
450
500
Anthro-PM10
2429
1264
3694
500
Anthro-PM2.5
1434
743
2178Ê
500
The ACE-Asia & TRACE-P observations are helping to reduce these uncertainties.
Huebert et al., (ACE-Asia JGR Overview) taken from Streets et al., JGR, 2003
B.Huebert, ACE-Asia, 03/03
8. How are aerosol properties and dynamics modified by the uptake
of gases?
C-130 RF06, 0351-0430, 448m asl
Yellow Sea Dust
C-130 MOI data:
8000
NSS and NH4, ng/sm3
Dust can modify
pollutant
chemistry and
become coated
with hygroscopic
salts in the
process.
6000
NSS
2000
4000
1000
2000
0
NO3- and Soluble Ca, ng/sm3
3000
0
0.1
2
3
4
5
6
7 8 9
1
2
3
GM Aerodynamic Diameter, µm
4
5
6
7 8 9
10
Kline, Huebert, Howell, Bertram, Blomquist, Zhuang, and Heath, Chemical and physical size
distributions vs altitude during ACE-Asia, J. Geophys. Res., in prep (ACE-Asia Special Issue B),
2003.
B.Huebert, ACE-Asia, 03/03
Clearly most NO3- was coarse and most SO4= was fine.
But what were their origins?
1.0
Was SO2
adsorbed by the
alkaline dust, or
was some of this
large-particle
sulfate from
gypsum at the
source?
Coarse NO3Fraction
0.8
0.6
0.4
0.2
0
5
10
15
20x10
3
Total_soluble_Ca_ng/sm3
0.0
0.0
0.2
0.4
0.6
Coarse NSS fraction
0.8
1.0
Was HNO3
adsorbed, or was
some Ca(NO3)2
from fertilizer?
Kline, Huebert, Howell, Bertram, Blomquist, Zhuang, and Heath, Chemical and physical size
distributions vs altitude during ACE-Asia, J. Geophys. Res., in prep (ACE-Asia Special Issue B),
2003.
B.Huebert, ACE-Asia, 03/03
What unknowns remain?
Why do the some values from surface sites and the C-130 differ?
Is it a measurement problem or a real difference?
C-130/R.B.: C130/R.B.: C130/R.B.:
same air
advection- statistical
parcel*
matched* comparison
all
aerosol
light scatter
[Mm-1]
low RH, 550nm D<1µm
aerosol
only
all
aerosol
light absorption
[Mm-1]
low RH, 550nm D<1µm
aerosol
only
1.15 (7)
1.03 (7)
1.19 (7)
1.23 (5)
Sarah Masonis Harmony paper
1.17 (4)
0.93
0.65
1.07
0.68
1.09 (4)
0.71
0.52
0.94
0.59
1.22 (4)
1.20
0.86
1.39
1.04
1.19 (2)
1.20
1.22
1.58
1.33
C-130/G os.: C130/Gos.: C130/Gos.:
same air
advection- statistical
+
parcel*
matched*+ comparison
1.35 (5)
1.11 (4)
1.14 (5)
1.03 (4)
1.09 (4)
1.06 (3)
0.98 (4)
0.93 (3)
1.34 (5)
1.11 (4)
1.12
0.98
1.11
0.96
1.21 (5)
1.12 (4)
0.88
0.48
0.77
0.78
1.07 (4)
1.04 (3)
0.91
0.57
0.95
1.01
1.00 (4)
1.04 (3)
1.18
0.66
1.05
1.25
B.Huebert, ACE-Asia, 03/03
What unknowns remain?
Need better total aerosol mass measurements, esp in dust
Need to standardize BC/EC measurements
Need to standardize many other measurements, too!
Need profile (airborne) measurements near dust source regions
Need evolution observations
…and many more...
etc.
B.Huebert, ACE-Asia, 03/03
What have we learned from ACE-Asia?
1. Air pollution changes dust aerosols in many ways, adding
black carbon, toxic materials, and acidic gases to the mineral
particles. These change its impact on health, climate, and the
delivery of nutrient iron to the remote Pacific ocean.
2. The dust that goes from East Asia to the Pacific does not
absorb nearly as much light as the dark aerosol from South
Asia or some previous Saharan dust data. There are dramatic
regional differences in the optical properties of aerosols.
3. Combining ACE-Asia suborbital and satellite measurements
yields monthly average (April 2001), cloud-free aerosol
radiative forcing at the surface in ACE-Asia exceeding -30
W m-2 in a plume downwind of Japan and in the Yellow Sea,
East China Sea, and Sea of Japan.
B.Huebert, ACE-Asia, 03/03
ACE-Asia Ship and Aircraft Platforms
B.Huebert, ACE-Asia, 03/03
ACE-Asia Participants and Resources
>100 Scientific
Groups
13 Countries
Surface Sites
Aircraft
>30 in Japan, China,
Korea, Chinese Taipei,
Hawaii
NSF/NCAR C-130
China, Japan, South
Korea, Chinese Tapiei,
USA, Canada, France,
Germany, Australia,
UK, India, Russia,
Netherlands
Forecast Models
>35 Funding
Agencies
Satellites
MATCH, NCAR
CFORS, Kyushu/Iowa
GOCART, Goddard
TERRA
SeaWiFS
CIRPAS Twin Otter
ARA KingAir
Ships
R/V Ron Brown
R/V Mirai
Lidars
ADNet, in Japan, Korea,
China
SABLE on C-130
AVHRR
GMS
B.Huebert, ACE-Asia, 03/03
ACE-Asia Network Observations:
Courtesy PMEL
B.Huebert, ACE-Asia, 03/03
Understanding Climate: Aerosol Forcings Cause the
Largest Uncertainty in the Earth’s Radiation Budget
Source: IPCC Third Assessment Report
Source: IPCC ThirdB.Huebert,
Assessment
Report
ACE-Asia,
03/03
Instrument Intercomparisons - Harmony
How confident can we be of any given measurement?
KingAir: 1
P-3: 2
C-130
Kosan
7
3
2
3-5
Ron Brown
B.Huebert, ACEAsia, 03/03
Twin Otter
Harmony - what can we learn from it?
Ratio C-130/Ron Brown
5-Apr-05
9-Apr-05
13-Apr-01
17-Apr-01
EXTENSIVE PARAMETERS: C-130 R Brn ratio C-130 R Brn ratio C-130 R Brn ratio C-130 R Brn ratio
ambient RH 53
56 0.94
83
93
0.89 46
52 0.90 55
69 0.80
Total 550 Scatt, amb RH
58
52
1.11
168
275
0.61
127
103
1.24
50
50
1.00
Total abs, 550nm:
4.6
7.3
0.63
15.9
8.6
1.84 11.8
9.0
1.31
7.6
7.1
1.08
1.85 2.28*
1.79
2.34
1.48
1.84
1.78
2.43
0.91
0.85
0.92
0.90
0.92
0.85
0.88
INTENSIVE PARAMETERS:
Total f(RH), 40-85%RH
Total SSA
0.88
LEGEND:
= C-130 parameter is larger
= R. Brn parameter is larger
= two values are equal!
1. The certainty that any individual number represents a region
2. The uncertainty in average quantities from each platform
These are very different things.
Courtesy Sarah Masonis et al.
B.Huebert, ACE-Asia, 03/03