GLOBAL CONSTRAINTS ON BIOGENIC VOC EMISSIONS GLOBAL CONSTRAINTS ON BIOGENIC VOC EMISSIONS FROM ATMOSPHERIC OBSERVATIONSFROM ATMOSPHERIC OBSERVATIONS

Daniel J. Jacob with Paul I. Palmer, Dorian S. Abbot, May Fu, Brendan Field,

Mat J. Evans, Yaping Xiao

and Randall V. Martin (Dalhousie U. ), Kelly V. Chance (Harvard-Smithsonian), Hanwant B. Singh (NASA-Ames), Joost DeGouw (NOAA/AL), Armin Hansel (U.

Innsbruck), Don Blake (UCI), Nicholas Jones (U. Woolagong)

PART1: PART1:

MAPPING OF ISOPRENE EMISSIONS USINGMAPPING OF ISOPRENE EMISSIONS USING HCHO COLUMN MEASUREMENTS FROM SPACE HCHO COLUMN MEASUREMENTS FROM SPACE

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

MEASUREMENT OF HCHO COLUMNS MEASUREMENT OF HCHO COLUMNS FROM THE GOME SATELLITE INSTRUMENTFROM THE GOME SATELLITE INSTRUMENT

(P.I. John Burrows)(P.I. John Burrows)

• HCHO column is determined from backscattered solar radiance in 340 nm absorption band

• Instrument is 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

Expect higher-resolution measurements soon from SCIAMACHY (30x60 km2, launched 2002) and OMI (13x24 km2, to be launched in June)

RETRIEVING SLANT COLUMNS FROMRETRIEVING SLANT COLUMNS FROM SOLAR BACKSCATTER MEASUREMENTS SOLAR BACKSCATTER MEASUREMENTS

absorption

wavelength

Slant optical depth

EARTH SURFACE

Scattering by Earth surface and by atmosphere

Backscatteredintensity IB

“Slant column”

])()(ln[

1

2

B

BS I

I

SeffS

FITTING OF HCHO FITTING OF HCHO SLANT COLUMNS SLANT COLUMNS

FROM GOME SPECTRA FROM GOME SPECTRA

[Chance et al., 2000][Chance et al., 2000]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

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)

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

coscos1

GAMF

IN SCATTERING ATMOSPHERE, IN SCATTERING ATMOSPHERE, AMF DEPENDS ON VERTICAL AMF DEPENDS ON VERTICAL DISTRIBUTION OF ABSORBERDISTRIBUTION OF ABSORBER

Observations (Y.N. Lee)Model

SOS (southeast U.S., Jul 1995)

Use GEOS-CHEM chemical transport model to specify shape of vertical profile for given scene

HCHO

AMF CALCULATION FOR SCATTERING ATMOSPHERE AMF CALCULATION FOR SCATTERING ATMOSPHERE

0

)()( dzzSzwAMFAMF G

GeometricAMF

GOME sensitivity= f (sun angle,albedo, aerosols,cloud…)RADIATIVETRANSFERMODEL

Vertical concentrationprofile shapefactor (normalized)

ATMOSPHERIC CHEMISTRY MODEL (GEOS-CHEM)

Vertical column = Slant column

AMF

From GOME

From model

GOME sensitivityw(z)

HCHO mixing ratioprofile S(z) (GEOS-CHEM)

what GOMEsees

AMFG = 2.08actual AMF = 0.71

ILLUSTRATIVE PROFILE FOR SCENE OVER TENNESSEE

FORMALDEHYDE COLUMNS FROM GOME: July 1996 meansFORMALDEHYDE COLUMNS FROM GOME: July 1996 means

…compare to GEOS-CHEM including GEIA biogenic VOC emissions and EPA anthropogenic VOC emissions

GEOS-CHEM vs. GOME: R = 0.83, bias = +14%

RELATING HCHO COLUMNS TO VOC EMISSIONRELATING HCHO COLUMNS TO VOC EMISSION

VOCi HCHOh (340 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

SEASONALITY OF GOME HCHO COLUMNS (9/96-8/97)SEASONALITY OF GOME HCHO COLUMNS (9/96-8/97)Largely reflects seasonality of isoprene emissions;Largely reflects seasonality of isoprene emissions;

general consistency with GEIA but also some notable differencesgeneral consistency with GEIA but also some notable differences

SEP

AUG

JUL

OCT

MAR

JUN

MAY

APR

GOME GEOS-CHEM (GEIA) GOME GEOS-CHEM (GEIA)

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

OZARKS “ISOPRENE VOLCANO” AS SEEN BY GOMEOZARKS “ISOPRENE VOLCANO” AS SEEN BY GOME(but not always)(but not always)

GOME HCHO columns over the Ozarks, July 1996: daily orbits and relationship to temperature

Temperature dependenceof isoprene emission (GEIA)

ULTIMATE YIELD OF HCHO ULTIMATE YIELD OF HCHO FROM ISOPRENEFROM ISOPRENE Uncertainty in peroxide recycling

under low-NOx conditions:

OH

.OO

NO

HCHO, MVK, MACR…

HO2

HOOh,OH

?

Isoprene peroxides are recycled in GEOS-CHEM (consistent with MCM)

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

Mod

el H

CH

O c

olum

n [1

016 m

olec

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

ISOPRENE EMISSION ISOPRENE EMISSION INVENTORIES, JULY1996INVENTORIES, JULY1996

GEIA (7.1 Tg)

BEIS2 (2.6 Tg)

GOME top-down (5.7 Tg)

Paui Palmer to show comparisonsto MEGAN inventory Wednesday

MODEL vs. OBSERVED SURFACE HCHOMODEL vs. OBSERVED SURFACE HCHOMean daytime HCHO observations

Jun-Aug 1988-1998 GEOS-CHEM simulation with“GOME” isoprene emissions

Inventory r2 BiasGOME 0.71 -9%GEIA 0.47 +17%BEIS2 0.58 -40%

high outliers

GOME isoprene emission inventory gives better fit to surface HCHO data than either GEIA or BEIS2

WHAT ABOUT THE REST OF THE WORLD?WHAT ABOUT THE REST OF THE WORLD?We’re starting to look at China

High emissions from forests in NE China? Need to be careful about possible fire influence

GOME (July 1997) GEOS-CHEM using GEIA (July 1997)

PART 2:PART 2:

GLOBAL BUDGET OF METHANOLGLOBAL BUDGET OF METHANOL

GLOBAL GEOS-CHEM BUDGET OF METHANOL (Tg yrGLOBAL GEOS-CHEM BUDGET OF METHANOL (Tg yr-1-1))with (in parentheses) ranges of previous budgets from Singh et al. [2000],

Heikes et al. [2002], Galbally and Kirstine [2003], Tie et al. [2003]

Plant growth: 128 (50-312)

Oceanuptake:11 (0-50)

Plant decay: 23 (13-20)

Biomass burning: 9 (6-13)Biofuels: 3

Urban: 4 (3-8)

CH3OHlifetime 10 days

(5-12)

VOC CH3O2

CH3O2 (85%)RO2 (15%)

Atmosphericproduction:37(18-31)

OH130

OH(aq) - clouds<1 (5-10)

Dry dep. (land) : 56Wet dep.: 12NPP based,

x3 for youngleaves

SIMULATED METHANOL SIMULATED METHANOL CONCENTRATIONS IN CONCENTRATIONS IN

SURFACE AIRSURFACE AIR

Representative observationsIn ppbv [Heikes et al., 2002]:

• Urban: 20 (<1-47)• Forests: 10 (1-37)• Grasslands: 6 (4-9)• cont. background: 2 (1-4)• NH oceans: 0.9 (0.3-1.4)

January

July

ppb

METHANOL-CO RELATIONSHIP OVER N. INDIAN OCEANMETHANOL-CO RELATIONSHIP OVER N. INDIAN OCEANINDOEX cruise [Wisthaler et al., 2002]

Positive correlation reflects outflow from India, where CO is mainly from combustion and methanol mostly from terrestrial biosphere

Small dots: obsLarge dots: model

METHANOL IN ASIAN METHANOL IN ASIAN OUTFLOW OVER PACIFICOUTFLOW OVER PACIFIC

Observed [H.B. Singh]ModelPlant growth tracerBiomass burning tracer

TRACE-P campaign,March-April 2001

METHANOL AT NORTH AMERICAN HIGH LATITUDES METHANOL AT NORTH AMERICAN HIGH LATITUDES (TOPSE MISSION) : MODEL (red) vs. OBSERVED (black)(TOPSE MISSION) : MODEL (red) vs. OBSERVED (black)

Observations from D.R. Blake (U.C. Irvine)

METHANOL VERTICAL PROFILES OVER S. PACIFICMETHANOL VERTICAL PROFILES OVER S. PACIFIC

Could the atmospheric source from CH3O2 + CH3O2 be underestimated?

Could there be a biogenic VOC “soup” driving organic and HOx chemistryin the remote troposphere?

In model over S. Pacific, CH4 OH

CH3O2

HO2 CH3OOHNO

HCHOCH3O2 0.6 CH3OH +…

~ 70%

~ 20%5-10%

Photochemical model calculations for same data set [Olson et al., 2001] are 50% too high for CH3OOH, factor of 2 too low for HCHO

0 0.6 1.2 1.8 2.4 3 0 0.6 1.2 1.8 2.4 3 0 0.6 1.2 1.8 2.4 3Methanol, ppbv

model atmospheric source

obs. FromH.B. Singh

PART 3:PART 3:

ACETONE. ACETALDEHYDE, HCNACETONE. ACETALDEHYDE, HCN

GLOBAL GEOS-CHEM BUDGET OF ACETONE (Tg yrGLOBAL GEOS-CHEM BUDGET OF ACETONE (Tg yr-1-1))from Jacob et al. [2002] with photolysis update from Blitz et al. [2004]with photolysis update from Blitz et al. [2004]

Vegetation: 33 (22-42)

Oceanuptake:14 19

Plant decay: 2 (-3 - 7)

Biomass burning: 5 (3-7)

Urban: 1 (1-2)

(CH3)2COlifetime 15 days 18 days

OH46

27

Dry dep. (land) : 9

propanei-butane

OH

terpenesMBO

OH, O3

h

microbes DOC+hv

Oceansource:27 (21-33)

21 (16-26)

7 (3-11)

28

37

12

OCEANIC SOURCE OF ACETONE IN MODELOCEANIC SOURCE OF ACETONE IN MODELNEEDED TO MATCH OBSERVATIONS OVER S. PACIFICNEEDED TO MATCH OBSERVATIONS OVER S. PACIFIC

a priori sources/sinks; 2 = 1.3 Optimized sources/sinks(including “microbial” ocean sink,photochemical ocean source); 2 = 0.39

from Jacob et al. [2002]

obs from Solberg et al.[1996]

obs. FromH.B. Singh

MORE RECENT AIRCRAFT DATA IMPLY MORE RECENT AIRCRAFT DATA IMPLY A NET OCEANIC SINK FOR ACETONEA NET OCEANIC SINK FOR ACETONE

ObservedModel

TRACE-P observations over tropical North Pacific in spring [Singh et al., 2003]

ETHANE [pptv]

AC

ETO

NE

[ppt

v]

500 1000 1500 2000 2500 3000 3500

500

1000

1500

2000

2500

Correlation between ACETONE and other tracers during TRACEP (Stratospheric influence filtered out)

CO [pptv]

AC

ETO

NE

[ppt

v]100 200 300 400 500

500

1000

1500

2000

2500

HCN [pptv]

AC

ETO

NE

[ppt

v]

200 400 600 800 1000

500

1000

1500

2000

2500

METHANOL [pptv]

AC

ETO

NE

[ppt

v]

0 2000 4000 6000

500

1000

1500

2000

2500

CORRELATION OF ACETONE WITH TRACERS OF SOURCES IN ASIAN OUTFLOW (TRACE-P DATA)

Ace

tone

[pp

tv]

CO [pptv]

Methanol [pptv]HCN [pptv]

Ethane [pptv]A

ceto

ne [

pptv

]

Ace

tone

[pp

tv]

Ace

tone

[pp

tv]

Acetone = 0

+1 [Ethane]

+2 [HCN]

+ 3 [Methanol]

Intercept = 200 pptv

Acetone = 0

+1 [CO]

+2 [HCN]

+ 3 [Methanol]

Intercept = 238 pptv

Multiple regression:Propane source Continentalsource

Biomass burning source

Biogenicsource

How to explain thepervasive 200 pptv acetone background?

HIGH CONCENTRATIONS OF ALDEHYDES HIGH CONCENTRATIONS OF ALDEHYDES OVER REMOTE NORTH PACIFICOVER REMOTE NORTH PACIFIC

Singhet al. [2003]

Inconsistent with observed PAN/NOx [Staudt et al., 2003]

…Also inconsistent with observed PAN/PPN ~100!

HOW RELIABLE ARE THE OBSERVATIONS?

GLOBAL GEOS-CHEM BUDGET OF HCN (Tg N yrGLOBAL GEOS-CHEM BUDGET OF HCN (Tg N yr-1-1))from Li et al. [2003]

Vegetation: ?

Oceanuptake:0.73

Biomass burning: 0.63

HCNlifetime 5 mos.

OH

0.1

Residentialfuel: 0.2

HCN(aq)/CN-

3 mos.

FTIR SURFACE-BASED MEASUREMENTS OF HCN COLUMNSFTIR SURFACE-BASED MEASUREMENTS OF HCN COLUMNS

Lines are model values

Japan Kitt Peak

Jungfraujoch Spitzbergen

CONFIRMATION OF BIOMASS BURNING SOURCE, CONFIRMATION OF BIOMASS BURNING SOURCE, OCEAN SINK IN TRACE-P AIRCRAFT DATAOCEAN SINK IN TRACE-P AIRCRAFT DATA

Mean vertical profileover remote N. Pacific Correlation with CO

Li et al. [2003]; HCN observations from H.B. SIngh

SIMULATED GLOBAL DISTRIBUTION OF HCNSIMULATED GLOBAL DISTRIBUTION OF HCN[Li et al., 2003][Li et al., 2003]

Lauder

Neumayer

……BUT MODEL UNDERESTIMATES RECENT HCN BUT MODEL UNDERESTIMATES RECENT HCN COLUMN OBSERVATIONS AT NEUMAYER COLUMN OBSERVATIONS AT NEUMAYER

Obs,Neumayer(N. Jones)

Obs,Lauder(C. Rinsland)

Model,Neumayer

Model, Lauder

Need better understanding of HCN(aq)/CN- chemistry in ocean and of role of terrestrial biosphere in HCN budget

Southern Ocean is not a sink for HCN; compensation point?