Languages
Pages
Legal
Conclusions & Future WorkTransported smoke measured during four flights (Sept. 4, 6, 13
and 14)
• No smoke measured at ground level
• AOD-to-PM higher than expected
• Aerosol was aged agricultural smoke from the Mississippi
River Valley
• Aerosol aging increases smoke hygroscopicity by 36%
• f(RH) of 1.5 for aged smoke / 1.1 for fresh smoke
• and thus increases AOD more than fresh smoke would
Future work will look at AERONET and ground-based PM2.5
measurements in order to study:
• the frequency of these long-range transport events
• the spatial extent of smoke transport in the southeast U.S.
DISCOVER-AQ
DISCOVER-AQ was funded by NASA’s Earth Venture-1 Program through the Earth System Science
Pathfinder (ESSP) Program Office. We wish to thank the ESSP Program Office for the support, the
NASA Wallops Flight Facility, the pilots, flight crew, and the entire DISCOVER-AQ Science Team.
We also wish to thank the entire SEAC4RS science team.
Long-Range Transport of Agricultural Smoke to
Houston, TX: Effects on Aerosol Optical DepthsA.J. Beyersdorf ([email protected])1, S. Burton1, G. Chen1, J. Lin2, R. Martin1, R. Moore1,
A. Nenes2, K.L. Thornhill1, E.L. Winstead1, L.D. Ziemba1 & B.E. Anderson1
1NASA Langley Research Center, 2Georgia Institute of Technology
Vertical profiles of extinction during DISCOVER-AQ-Texas varied amongst flights
• Boundary layer – low loadings of 30-70/Mm
• 2,500-10,000 ft – transported smoke caused increased aerosol loadings for
September 13-14
September 13th
• Smoke measured by both the HSRL
and in situ measurements
• Highest loadings in the north of the
flight region
• Back trajectory for layer aloft from a
region of agricultural fires
Differences in Back Trajectories
• Boundary layer – low loadings of 30-70/Mm
• 2,500-10,000 ft – transported smoke caused increased aerosol loadings for
September 13-14
Smoke Transport
2.AQ.1
Measuring surface level particulate concentrations remains a challenge for Earth-
observing satellites due to:
1) variability in aerosol vertical distribution, and
2) the effects of aerosol composition and hygroscopicity on optical properties.
DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically
Resolved Observations Relevant to Air Quality) is a multi-year project aimed at
understanding the variables that affect remote sensing measurements in U.S. urban
areas. Four campaigns were performed in regions with differing aerosol composition
and meteorology:
Baltimore & Washington, DC, Summer 2011
San Joaquin Valley, CA, Winter 2012
Houston, TX, Summer 2012
Denver, CO, Summer 2013
Results from Previous Campaigns
Maryland
• aerosol was composed of a mixture of organics and ammonium sulfate
• aerosol present in a well-mixed deep haze layer (~ 7500 ft)
California
• primarily ammonium nitrate aerosol
• contained in a very shallow boundary layer (~ 2000 ft) except for the last two flights
AOD-to-PM
• The AOD-to-PM correlation is dependent on the height of the haze layer (boundary +
residual) with Maryland having a higher ratio than measured during California.
15000
12500
10000
7500
5000
2500
0
Alt
itu
de
(ft
)
NormalizedExtinction
RF01-09
RF11-12
15000
12500
10000
7500
5000
2500
0
Alt
itu
de (
ft)
4003002001000
Extinction (Amb. RH at 532nm)
15000
12500
10000
7500
5000
2500
0
Alt
itu
de
(ft
)
NormalizedExtinction
15000
12500
10000
7500
5000
2500
0
Alt
itu
de
(ft
)
4003002001000
Extinction (Amb. RH at 532nm)
Maryland California
9 Flights between Sept. 4th and 26th, 2013
• P-3B aircraft
• 24 spirals (1,000-15,000 ft above ground levels)
over 8 ground sites
• In situ measurements of aerosols & trace gases
• Aerosol number concentration, scattering,
absorption, size & composition (by SP2 and
PILS; particle into liquid sampler)
• B-200 aircraft (30,000 ft)
• High Resolution Spectral Lidar (HSRL)
Sampling of agricultural fires during transit flight
No correlation between ambient AOD and
particulate mass during DAQ-TX
• Ambient AOD (measured by the P3) varied
between 0.06 (Sept 26th) & 0.32 (Sept. 14th)
• Flight day particulate mass was less variable
(6-11 mg/m3)
DISCOVER-AQ Texas
Downtown
Houston
Galveston
Conroe
0.6
0.4
0.2
0.0
AO
D
403020100
PM(mg/m3)
Measured by PILS below 1000 ft
Texas (colored by altitude of maximum extinction) fit_Over_MD_AOD fit_Over_CA_AOD_without_highs
15000
12500
10000
7500
5000
2500
0
Alt
itu
de
(ft
)
1251007550250
Extinction (Amb, 532nm)
RF07 (9-24) RF08 (9-25) RF09 (9-26)
15000
12500
10000
7500
5000
2500
0
Alt
itu
de
(ft
)
1251007550250
Extinction (Amb, 532nm)
RF03 (9-11) RF04 (9-12) RF05 (9-13) RF06 (9-14)
15000
12500
10000
7500
5000
2500
0
Alt
itu
de
(ft
)
1251007550250
Extinction (Amb, 532nm)
RF01 (9-4) RF02 (9-6)
15000
12500
10000
7500
5000
2500
0
Alt
itu
de (
ft)
1251007550250
Extinction (Amb, 532nm)
15000
12500
10000
7500
5000
2500
0
Alt
itu
de (
ft)
Normalized Extinction
West
Houston
4
3
2
1
0
Alt
itu
de (
km
)
30.430.230.029.829.629.429.2
Latitude
806040200
0913, Circuit 1 - Extinction
LIDAR
In Situ Measurements
4
0
Extinction
29.2 29.6 30.0 30.4Latitude
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Pre
ss
ure
Alt
itu
de
806040200
Scattering & Absorption (/Mm, green)
Aerosol Size – smoke was larger than fresher aerosol
measured in the boundary layer
Single Scattering Albedo – smoke had a higher SSA than
the boundary layer and fresh agricultural fires indicating
secondary aerosol formation
Hygroscopicity – fresh smoke had an average f(RH) of
1.1 while the aged smoke averaged 1.5
Smoke Properties
4000
3000
2000
1000
0Nu
mb
er
(dN
dlo
gD
p)
102 4 6 8
1002 4 6 8
1000
Diameter
Fre
qu
en
cy
2.82.62.42.22.0
Scat. Ang. Exp.
Boundary LayerElevated Layer
Fre
qu
en
cy
2.01.81.61.41.21.0
f(RH)
Boundary LayerElevated LayerFresh. Ag. Fire
Fre
qu
en
cy
1.000.950.900.85
SSA
Boundary LayerElevated Layer
Fre
qu
en
cy
1.000.950.900.85
SSA
Elevated LayerAg. Fire
Period 1 Period 2 Period 3
Aerosol Size Single Scattering Albedo
Hyg
rosco
pic
ity
70
60
50
40
30
20
280270260250240230220210200
SEAC4RS & ARCTAS Biomass BurningSEAC4RS Fire Plumes
• Preliminary identification by Bob
Yokelson including western U.S.
wildfires and agricultural fires in
the southeast.
• Additional identification to follow
for more aged plumes downwind
of the Rim fire.
ARCTAS Fire Plumes
• 495 plumes identified by
Hecobian et al. (ACP, 2011)
• Aged Asian wildfires sampled
over Alaska
• Fresh Canadian and California
wildfires
Aged Asian
Wildfires
(ARCTAS)
Fresh Canadian
Wildfires
(ARCTAS)
SEAC4RS
Wildfires SEAC4RS
Ag. Fires
Fresh California
Wildfires
(ARCTAS)
Agricultural Fires (in comparison to wildfires)
• lower modified combustion efficiencies → smoldering fires
• MCE = (ΔCO2)/(ΔCO+ΔCO2)
• high particulate emissions & lower single scattering albedo
Western Wildfires (in comparison to ARCTAS fires)
• highest single scattering albedos
• f(RH) less than 1 → indicative of soot restructuring
2.8
2.6
2.4
2.2
2.0
1.8Scat.
An
g.
Exp
on
en
t1.000.950.900.85
Modified Combustion Efficiency
Agricultural Fires4.0
3.5
3.0
2.5
2.0
1.5Ab
s.
An
g.
Exp
on
en
t
1.000.950.900.85
Modified Combustion Efficiency
1.00
0.95
0.90
0.85Sin
gle
Scat.
Alb
ed
o
1.000.950.900.85
Modified Combustion Efficiency
Changes in aerosol intensive properties with flame conditions (MCE)
• Flaming conditions (high MCE) gives:
• higher scattering angstrom exponent (smaller aerosol)
• lower absorption angstrom exponent (less organic coating)
• lower single scattering albedo (darker smoke)
0.5
0.4
0.3
0.2
0.1
0.0
AO
D
20151050
PM from PILS (<1000 ft)All ProfilesFlight Averages colored by altitude
of max. extinction (black is highest)
0.6
0.4
0.2
0.0
AO
D
403020100
PM(mg/m3)
Measured by PILS below 1000 ft
Maryland California fit_Over_MD_AOD fit_Over_CA_AOD_without_highs
MarylandSlope = 0.027
CaliforniaSlope = 0.006
20
15
10
5
0
PM
302520151050
Day in September
PILS Mass (below 1000 ft)PM2.5 (9am - 5pm)
Galveston Conroe Deer Park
0.4
0.3
0.2
0.1
0.0P3-B
AO
D (
Am
b,
53
2n
m)
302520151050
Day in September
Top Related