with paui i. palmer, tzung-may fu, dylan b. millet, dorian s. abbot
DESCRIPTION
MAPPING OF VOLATILE ORGANIC COMPOUND (VOC) EMISSIONS USING SATELLITE OBSERVATIONS OF FORMALDEHYDE COLUMNS Daniel J. Jacob. with Paui I. Palmer, Tzung-May Fu, Dylan B. Millet, Dorian S. Abbot. and Kelly V. Chance, Thomas Kurosu (Harvard SAO/CFA). - PowerPoint PPT PresentationTRANSCRIPT
MAPPING OF VOLATILE ORGANIC COMPOUND (VOC) MAPPING OF VOLATILE ORGANIC COMPOUND (VOC) EMISSIONS USING SATELLITE OBSERVATIONSEMISSIONS USING SATELLITE OBSERVATIONS
OF FORMALDEHYDE COLUMNSOF FORMALDEHYDE COLUMNS
Daniel J. JacobDaniel J. Jacobwith Paui I. Palmer, Tzung-May Fu, Dylan B. Millet, Dorian S. Abbot
and Kelly V. Chance, Thomas Kurosu (Harvard SAO/CFA)
supported by NASA Atmospheric Chemistry Modeling and Analysis Program
SATELLITE OBSERVATIONS OF TROPOSPHERIC COMPOSITIONSATELLITE OBSERVATIONS OF TROPOSPHERIC COMPOSITION…a rapidly growing resource!…a rapidly growing resource!
Sensor TOMS GOME IMG MOPITT MISR MODIS AIRS SCIA-MACHY
TES OMI
Platform (launch)
multi
(1979-)
ERS-2 (1995)
ADEOS
(1996)
Terra Aqua
(1999) (2002)
Envisat (2002)
Aura
(2004)
ozone X (tropics)
X X
aerosol X X
CO X X X X
NO2 X X X
HNO3 X
HCHO X X X
SO2 X X X
BrO X X X
IMPORTANCE OF NON-METHANE VOC EMISSIONS IMPORTANCE OF NON-METHANE VOC EMISSIONS FOR ATMOSPHERIC CHEMISTRY FOR ATMOSPHERIC CHEMISTRY
Vegetation
~ 600 Tg C yr-1
Isoprene, terpenes,oxygenates…
Biomass burning
~ 50 Tg C yr-1
Alkenes, aromatics,oxygenates…
~ 200 Tg C yr-1
Alkanes, alkenes,aromatics…
Industry
• Precursors of tropospheric ozone• Precursors of organic aerosols• Sinks of OH
SPACE-BASED MEASUREMENTS OF HCHO COLUMNSSPACE-BASED MEASUREMENTS OF HCHO COLUMNSAS CONSTRAINTS ON VOC EMISSIONSAS CONSTRAINTS ON VOC EMISSIONS
VOC HCHOOxidation (OH, O3, NO3)
Emissions
many steps
hnm), OH
lifetime of hours
340 nm
solar backscatter
SPACE-BASED MEASUREMENTS OF ATMOSPHERIC SPACE-BASED MEASUREMENTS OF ATMOSPHERIC COLUMNS BY SOLAR BACKSCATTERCOLUMNS BY SOLAR BACKSCATTER
absorption
wavelength
Slant optical depth
Scattering by Earth surface and by atmosphere
Backscatteredintensity IB
“Slant column”
])(
)(ln[
1
2
B
BS I
I
SeffS
Examples: TOMS, GOME, SCIAMACHY, MODIS, MISR, OMI, OCOApplications to retrievals of O3, NO2, HCHO, BrO, CO, CO2, aerosols…
/S AMF Vertical column
The air mass factor (AMF) depends on viewing geometry and radiative transfer
THE GOME INSTRUMENTTHE GOME INSTRUMENT
• Instrument in polar sun-synchronous orbit, 10:30 a.m. observation time
• 320x40 km2 field of view, three cross-track scenes
• Complete global coverage in 3 days
• Operational since 1995
• HCHO column is determined from backscattered solar radiance in 340 nm absorption band
• Concurrent retrievals of cloud fractions, tops, optical depths
FITTING OF HCHO FITTING OF HCHO SLANT COLUMNS SLANT COLUMNS
FROM GOME SPECTRA FROM GOME SPECTRA
s = 1.0 ± 0.3 x1016 cm-2
s = 3.0 ± 0.4 x1016 cm-2
s = 8.4 ± 0.7 x1016 cm-2
Fitting uncertainty of4x1015 molecules cm-3
corresponds to ~ 1 ppbv HCHO in lowest 2 km
Chance et al. [2000]
HCHO SLANT COLUMNS MEASURED BY GOME HCHO SLANT COLUMNS MEASURED BY GOME (JULY 1996) (JULY 1996)
High HCHO regions reflect VOC emissions from fires, biosphere, human activity
-0.5
0
0.5
1
1.5
2
2.5x1016
moleculescm-2
SouthAtlanticAnomaly(disregard)
detectionlimit
AIR MASS FACTOR (AMF) CONVERTS AIR MASS FACTOR (AMF) CONVERTS SLANT COLUMN SLANT COLUMN SS TO VERTICAL COLUMN TO VERTICAL COLUMN
SAMF
“Geometric AMF” (AMFG) for non-scattering atmosphere:
EARTH SURFACE
cos
cos1GAMF
IN SCATTERING ATMOSPHERE, AMF DEPENDS ON IN SCATTERING ATMOSPHERE, AMF DEPENDS ON VERTICAL DISTRIBUTION OF ABSORBERVERTICAL DISTRIBUTION OF ABSORBER
Use GEOS-Chem chemical transport model to specify shape of vertical profile for given scene
HCHO
340 nm
EARTH SURFACE
GOME sensitivityw(z)
HCHO mixing ratioprofile S(z) (GEOS-Chem)
what GOMEsees
AMFG = 2.08actual AMF = 0.71
AMF FOR A SCATTERING ATMOSPHERE
G
0
AMF = AMF ( ) ( )S z w z dz
Palmer et al. [2001]
QUANTIFYING AMF ERRORS USING AIRCRAFT PROFILESQUANTIFYING AMF ERRORS USING AIRCRAFT PROFILES
0-10 km spirals and profiles during ICARTT:In situ HCHO, clouds, aerosol extinction
[CH2O] (ppt)
ALT
(km)
0 1000 2000 30002
46
810
MEAS (NCAR)MEAS (URI)MOD (GEOS-CHEM)
Observed (Fried)Observed (Heikes)GEOS-Chem model
ICARTT mission over North America (summer 2004)
model
observed
AMF0.91 0.24
AMF
Mean HCHO profiles in ICARTT
(n = 89)
Clouds are the principal source of error Dylan B. Millet, Harvard
FORMALDEHYDE COLUMNS FROM GOME: July 1996 meansFORMALDEHYDE COLUMNS FROM GOME: July 1996 means
…compare to GEOS-Chem including GEIA biogenic VOC emissions and U.S. EPA anthropogenic VOC emissionsGEOS-Chem vs. GOME: R = 0.83, bias = +14%
Palmeret al. [2003]
SEASONALITY OF GOME HCHO COLUMNS (9/96-8/97)SEASONALITY OF GOME HCHO COLUMNS (9/96-8/97)largely reflects seasonality of isoprene emissionslargely reflects seasonality of isoprene emissions
SEP
AUG
JUL
OCT
MAR
JUN
MAY
APR
GOME GEOS-Chem (GEIA) GOME GEOS-Chem (GEIA)
Abbot et al. [2003]
INTERANNUAL VARIABILITY OF GOME HCHO COLUMNSINTERANNUAL VARIABILITY OF GOME HCHO COLUMNS
1995
1996
1997
1998
Augusts 1995-2001: correlation with temperature anomaly explains some Augusts 1995-2001: correlation with temperature anomaly explains some but not all of the HCHO column variabilitybut not all of the HCHO column variability
1999
2000
2001
GOME HCHO Temp. anomaly GOME HCHO Temp. anomaly
Abbotet al. [2003]
RELATING HCHO COLUMNS TO VOC EMISSIONRELATING HCHO COLUMNS TO VOC EMISSION
VOCi HCHOh (<345 nm), OHoxn.
k ~ 0.5 h-1
Emission Ei
smearing, displacement
In absence of horizontal wind, mass balance for HCHO column HCHO:
i ii
HCHO
y E
k
yield yi
… but wind smears this local relationship between HCHO and Ei depending on the lifetime of the parent VOC with respect to HCHO production:
Local linear relationshipbetween HCHO and E
VOC source Distance downwind
HCHOIsoprene
-pinenepropane
100 km
TIME-DEPENDENT HCHO YIELDS FROM VOC OXIDATIONTIME-DEPENDENT HCHO YIELDS FROM VOC OXIDATION
Palmer et al, [2005]
High HCHO signal from isoprene with little smearing, weak and smeared signal from terpenes; GEOS-Chem yields may be too low by 10-40% depending on NOx
Box model simulations with state-of-science MCM v3.1 mechanism
methylbutenol
HCHO COLUMN vs. ISOPRENE EMISSION RELATIONSHIPHCHO COLUMN vs. ISOPRENE EMISSION RELATIONSHIPIN GEOS-Chem MODELIN GEOS-Chem MODEL
Isoprene emission [1013 atomC cm-2 s-1]
NW NE
SESW
Mo
del
HC
HO
co
lum
n [
1016
mo
lec
cm-2
]
Results for U.S. quadrants in July 1996 simulation w/ 2ox2.5o horizontal resolution show: (1) dominance of isoprene emission as predictor of HCHO variability; (2) linear relationship between the two
Standard simulation
HCHO from simulationw/o Isoprene emission
We use this relationship to derive “top-down” isoprene emissions from the GOME HCHO column observations
R2 = 0.51
R2 = 0.65
R2 = 0.43
R2 = 0.49
GOME vs. MEGAN ISOPRENE EMISSION INVENTORIES (2001)GOME vs. MEGAN ISOPRENE EMISSION INVENTORIES (2001)
• Good accord for seasonal variation, regional distribution of emissions;• GOME 10-34% higher than MEGAN depending on month, differences in hot spot locations
Palmer et al. [2005]
MEGAN is a new inventory of isoprene emissions developed by Alex Guenther [Guenther et al., 2005]
EVALUATING GOME ISOPRENE EMISSION ESTIMATES EVALUATING GOME ISOPRENE EMISSION ESTIMATES vs. IN SITU FLUX MEASUREMENTS (2001)vs. IN SITU FLUX MEASUREMENTS (2001)
PROPHET forest site in northern Michigan (M. Pressley, WSU):also shown are local MEGAN isoperene emission inventory values
Palmer et al. [2005]
GO
ME H
CH
O C
olu
mn
[10
16 m
ole
c
cm
-2]
Southeast US average 32-38N; 100-85W
YEAR-TO-YEAR VARIABILITY OF GOME HCHO OVER SOUTHEAST U.S.YEAR-TO-YEAR VARIABILITY OF GOME HCHO OVER SOUTHEAST U.S.Amplitude and phase are highly reproducible
P. I. Palmer (Harvard)
WHAT DRIVES GOME HCHO TEMPORAL VARIABILITY WHAT DRIVES GOME HCHO TEMPORAL VARIABILITY OVER SOUTHEAST U.S. DURING MAY-SEPTEMBER?OVER SOUTHEAST U.S. DURING MAY-SEPTEMBER?
P.I. Palmer (Harvard)
Monthly mean GOME HCHO vs. surface air temperature;MEGAN parameterization shown as fitted curve
Temperature drives ~80% of the variance of monthly mean HCHO columns
GOME HCHO COLUMNS OVER EAST ASIA (1996-2001)GOME HCHO COLUMNS OVER EAST ASIA (1996-2001)
Relationship to VOC emissions far more complex than for N. America; biomass burning, isoprene, anthropogenic VOCs, direct HCHO emission all contribute
APRJAN
FEB
MAR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Tzung-May Fu (Harvard)
GOME vs. GEOS-Chem HCHO COLUMNS OVER EAST ASIAGOME vs. GEOS-Chem HCHO COLUMNS OVER EAST ASIA
APR
MAY
JUN
JUL
AUG
SEP
MEGAN biogenic emission inventory is far too low
T. M. Fu (Harvard)
0% 20% 40% 60% 80% 100%
Changchun
BengbuHefei
BeijingLangfang
QinghuangdaoShijiazhunag
TangshanNanyangXinyang
XuchangZhengzhou
SuizhouJiningJinan
QingdaoZouchengShanghai
TaiyuanWeinan
ChongqingLanzhouGuiyang
YinchuanKunming
HaMiUrumqi
Golmud
AnqingShishouWuhanXiantao
ChangdeChangsha
QiyangShaoyang
ZhangjiajieJi'an
JingdezhenJiujiang
LinchuanNanchang
BeihaiGuilin
HangzhouTaihu
Wenzhou
Ethane
Propane
ALK4
Ethene
PRPE
Benzene
Toluene
Xylene
Isoprene
VOC CONTRIBUTIONS TO HCHO PRODUCTION VOC CONTRIBUTIONS TO HCHO PRODUCTION IN CHINESE CITIES (JAN-FEB 2001)IN CHINESE CITIES (JAN-FEB 2001)
Ethane 0.3 % Benzene 0.4 %
Propane 0.3 % Toluene 2.4 %
ALK4 5.1 % Xylene 20.2 %
Ethene 19 % Isoprene 8.2 %
PRPE 43 %
B. Barletta (UCI), T.-M. Fu (Harvard)
Vehicle-generated xylenes could make a large contribution to HCHO columns
NC
CC
WC
SC
PRELIMINARY HCHO COLUMN DATA FROM OMIPRELIMINARY HCHO COLUMN DATA FROM OMI(launched on Aura in July 2004)(launched on Aura in July 2004)
26 Day Average: 24 September – 19 October 200426 Day Average: 24 September – 19 October 2004
K. Chance and T. Kurosu (Harvard CFA)