Dec 1996 June 1997 GOME HCHO column data molecules cm -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 Sciences Harvard University

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, NO x STRATOSPHERE TROPOSPHERE HO 2 OH NONO 2 H2O2H2O2 O3O3 O3O3 O2O2 hv, H 2 O hv HNO 3 OH HCHO + h   2HO 2 + CO (radical channel) HCHO + OH  HO 2 + CO + H 2 O 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 Altitude [km] measurements GEOS-CHEM model Defined background CH 4 + OH

Nadir-viewing SBUV instrument Launched April 1995 Pixel 320 x 40 km am cross-equator time Global coverage in 3 days O 3, NO 2, BrO, OClO, SO 2, HCHO, H 2 O, & cloud coverage Global Ozone Monitoring Experiment

HCHO slant column fitting 3 x molec cm -2 8 x molec cm -2 1  fitting uncertainty 4 x molec cm -2 Chance et al [2000] O 3 NO 2 BrO O 2 -O 2

vertical column = slant column /AMF satellite d  HCHO Earth Surface HCHO mixing ratio C(  )  lnI B /  Scattering weightsShape factor w(  ) = - 1/AMF G  lnI B /  Sigma coordinate (  ) S(  ) = C(  )  air /  HCHO AMF = AMF G  w(  ) S(  ) d  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 2x2.5 o resolution/26 vertical levels O 3 -NO x -VOC chemistry GEIA isoprene emissions Aerosol scattering: AOD:O 3 Dickerson et al, [1997]

[10 16 molec cm -2 ] GEOS-CHEM GOME HCHO columns – July 1996 r 2 = 0.7 n = 756 Bias = 11% HCHO fitted in UV (~340 nm) 1  uncertainty: 4 x molec cm -2

[10 16 molec cm -2 ] GOMEGEOS-CHEM July July 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  =  Y i E i i k HCHO HC i HCHO  Chemical loss k HCHO Emission E i HC oxidation k i (HCHO yield Y i )

HCHO yields from HCs SpeciesEmission [TgC month -1 ] HCHO Yield [C -1 ] Potential HCHO production [%] CH ISOP   - pinenes MBO HCHO CH 3 OH Total: 86%

L d,i = U Horizontal transport displaces HCHO signal Displacement length scale k i -k HCHO ln ( ) kiki k HCHO midmorning eg values K HCHO = 0.5h -1 ; U = 20kmh -1 ; [OH]=5E6 mol cm -3 ISOP L d,i  40 km CH 4 L d,i = many 1000s km CH 3 OH L d,i =100s km

GEOS-CHEM HCHO columns July 1996 [ molec cm -2 ] GEIA isoprene emissions

NWNE SESW Isoprene emission [10 13 atomC cm -2 s -1 ] Model HCHO column [10 16 molec cm -2 ] July 1996 (25-50 o N, o W) Slope S = Y/k HCHO model without isoprene

nS [10 3 s] r2r2 W lifetime [hours] Y [C -1 ] NW NE SE SW Yields consistent with photochemical model

[10 16 molec cm -2 ] GOMEGEOS-CHEM July July 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 Plane Isop Surface HCHO 7-15(11) Plane HCHO 3-11(7)

HCHO data over the Ozarks Missouri Illinois Kansas [ppb] Aircraft 350 m during July 1999 c/o Y-N. Lee, Brookhaven National Lab. OZARKS SOS 1999

[10 16 molec cm -2 ] GOMEGEOS-CHEM July July Surface temperature [K] Slant column HCHO [10 16 mol 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 data GEIABEIS2 r 2 = 0.53 Bias -3% r 2 = 0.65 Bias -30%

NWNE SESW Isoprene emission [10 13 atomC cm -2 s -1 ] Model HCHO column [10 16 molec cm -2 ] Model Transfer functions model without isoprene

[10 12 atom C cm -2 s -1 ] GOME isoprene emissions – July 1996

Consistency: GOME and in situ data r 2 = 0.77 Bias -12%

Global HCHO from GOME: July 1996 [10 16 molec cm -2 ]

ATSR Firecounts – July 1996

[10 16 molec cm -2 ] Global HCHO from GOME: Oct 1996

CONSTRAINING SEASONAL AND INTERANNUAL VARIABILITY IN BIOGENIC VOC EMISSIONS HCHO columns, Jun-Aug 1997 GOMEGEOS-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