Dec 1996

June 1997

GOME HCHO columndata

10

16 m

ole

cu

les c

m-2

North American Hydrocarbon Emissions Measured from Space

Paul Palmer, Daniel Jacob, Arlene Fiore, Randall Martin, Dorian Abbot, Kelly Chance,

Thomas Kurosu

Division of Engineering and Applied SciencesHarvard University

http://www.people.fas.harvard.edu/~ppalmer

Overview

• Why are accurate hydrocarbon emissions important?

•Relating measured HCHO columns to specific hydrocarbon emissions

•Are satellite observations consistent with in situ data?

•The future?

CO, hydrocarbons, NOx

STRATOSPHERE

TROPOSPHERE

HO2OH

NONO2

H2O2

O3

O3

O2

hv, H2O

hv

hvHNO3

OH

HCHO + h 2HO2 + CO (radical channel)

HCHO + OH HO2 + CO + H2O lifetime = few hrs

ppb

Summertime in situ HCHO datasets

Fried et al 1997

Harris et al 1989

Kleindienst et al 1988

Lee et al 1995, 1998

Martin et al 1991

McKeen et al 1997

OZIE -Guenther

Reimer et al 1998

Shepson et al 1991

Aircraft HCHO profile data

Southern Oxidant Study 1995

North Atlantic Regional Experiment 1997

[ppb]

Surface source (mostly isoprene+OH)

Continental outflow

Alt

itu

de

[km

]

Alt

itu

de

[km

]

measurements GEOS-CHEM model

Defined background CH4 + OH

• Nadir-viewing SBUV instrument

• Launched April 1995

• Pixel 320 x 40 km2

• 10.30 am cross-equator time

• Global coverage in 3 days

• O3, NO2, BrO, OClO, SO2, HCHO, H2O, & cloud coverage

Global Ozone Monitoring Experiment

HCHO slant column fitting

3 x 1016 molec cm-2

8 x 1016 molec cm-2

1 fitting uncertainty 4 x 1015 molec cm-2

Chance et al [2000]

O3

NO2

BrO

O2-O2

vertical column = slant column /AMF

satellite

dHCHO

Earth Surface

HCHO mixing ratio C()

lnIB/

Scattering weights

Shape factorw() = - 1/AMFG lnIB/

Sig

ma c

oord

inate

(

)

S() = C() air/HCHO

AMF = AMFG w() S() d1

1

0

GEOS-CHEM

AMF example - Tennessee

GEOS-CHEM S()

w()

S()

w() AMF

G

2.08

AMF

0.71

AMF calculation every GOME July 1996 scene...

GEOS-CHEM global 3D model:

101

•Driven by DAO GEOS met data

•2x2.5o resolution/26 vertical levels

•O3-NOx-VOC chemistry

•GEIA isoprene emissions

•Aerosol scattering: AOD:O3

Dickerson et al, [1997]

[1016molec cm-2]

GEOS-CHEM

GOME

HCHO columns – July 1996

r2 = 0.7 n = 756

Bias = 11%

HCHO fitted in UV (~340 nm)

1 uncertainty: 4 x 1015 molec cm-2

[1016 molec cm-

2]

GOME GEOS-CHEM

July 7 1996

July 20 1996

Isoprene “volcano”

mm

Global 3d model of chemistry

How do we validate satellite observations?

GOME,

MOPITT,

SCIAMACHY

TES, OMI

Relating HCHO columns to hydrocarbon emissions

•Absence of

transport = Yi Ei

i

kHCHO

HCi

HCHO

Chemical loss kHCHO

Emission Ei

HC oxidation ki (HCHO yield Yi)

HCHO yields from HCsSpecies

Emission[TgC month-

1]

HCHO Yield[C-1]

Potential HCHO production [%]

CH4 2.6 1.0 28.5

ISOP 7.3 0.45 32.0

-pinenes

1.1 0.8

0.019 0.045

0.23 0.39

MBO 0.8 0.06 0.53

HCHO 0.15 1.0 1.64

CH3OH 2.1 1.0 23.0 Total: 86%

L d,i = U

Horizontal transport displaces HCHO signalDisplacement length scale

ki -kHCHOln( )ki

kHCHO

midmorning eg values KHCHO = 0.5h-1; U = 20kmh-1; [OH]=5E6 mol cm-3

ISOP Ld,i 40 km

CH4 Ld,i = many 1000s km

CH3OH Ld,i =100s km

GEOS-CHEM HCHO columnsJuly 1996

[1016 molec cm-2]

GEIA isoprene emissions

NW NE

SESW

Isoprene emission [1013 atomC cm-2 s-1]

Mod

el H

CH

O c

olu

mn

[101

6 m

ole

c c

m-2

] July 1996 (25-50oN, 65-130oW)

Slope S = Y/kHCHO

model without isoprene

n S[103 s]

r2 lifetime[hours]

Y[C-1]

NW 1810

2.04 0.51 1.67 0.34

NE 2193

1.90 0.43 1.76 0.30

SE 1913

2.09 0.65 1.48 0.39

SW 1750

1.27 0.49 1.48 0.24

Yields consistent with photochemical model

[1016 molec cm-

2]

GOME GEOS-CHEM

July 7 1996

July 20 1996

Isoprene “volcano”

mm

The Ozarks• Dissected plateau - 129,500 sq km

• Oak forests – good isoprene emitters

"Trees cause more pollution than automobiles do."

Cambridge, MA

Ozark Isoprene Experiment 1998

Photos c/o Alex Guenther, NCAR

Result Summary

Type Spec ppb Alt [m] Local time

Balloon Isop 1-7 400-1000 0830-1930

Plane Isop 3-6 450-900 1800-2000

Surface HCHO 7-15(11) 0830-1930

Plane HCHO 3-11(7) 1300-1800

HCHO data over the Ozarks

Missouri Illinois

Kansas

[ppb]

Aircraft data @ 350 m during July 1999

c/o Y-N. Lee, Brookhaven National Lab.

OZARKS

SOS 1999

[1016 molec cm-

2]

GOME GEOS-CHEM

July 7 1996

July 20 1996

Surface temperature [K]

Sla

nt

colu

mn

HC

HO

[1

016 m

ol

cm

-2]

Temperature dependence of isoprene emission

Isoprene “volcano”

Global 3d model of chemistry

EPA BEIS2

GEIA

ppb

Summertime in situ HCHO datasets

Fried et al 1997

Harris et al 1989

Kleindienst et al 1988

Lee et al 1995, 1998

Martin et al 1991

McKeen et al 1997

OZIE -Guenther

Reimer et al 1998

Shepson et al 1991

Modeling in situ dataGEIA BEIS2

r2 = 0.53

Bias -3%

r2 = 0.65

Bias -30%

NW NE

SESW

Isoprene emission [1013 atomC cm-2 s-1]

Mod

el H

CH

O c

olu

mn

[101

6 m

ole

c c

m-2

]Model Transfer functions

model without isoprene

[1012 atom C cm-2 s-

1]

GOME isoprene emissions – July 1996

Consistency: GOME and in situ data

r2 = 0.77

Bias -12%

Global HCHO from GOME: July 1996

[1016 molec cm-2]

ATSR Firecounts – July 1996

[1016 molec cm-2]

Global HCHO from GOME: Oct 1996

CONSTRAINING SEASONAL AND INTERANNUAL VARIABILITY IN BIOGENIC

VOC EMISSIONSHCHO columns, Jun-Aug 1997GOME GEOS-CHEM

Summary

New methodology for HC emission from space-based HCHO columns

Isoprene is dominant HC for North American summertime

GOME shows Ozarks isoprene volcano

GOME data consistent with in situ data

Future work will include global mapping