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)

OMI HCHO RETRIEVALS AND MODIS FIRE COUNTSOMI HCHO RETRIEVALS AND MODIS FIRE COUNTS

JakartaJakarta

ChongqinChongqingg

(Red (Red Basin)Basin)