CONSTRAINTS OF ASIAN VOC SOURCES FROM GOME HCHO OBSERVATIONS Tzung-May Fu, Paul I. Palmer, Dorian S. Abbot, Daniel J. Jacob Atmospheric Chemistry Modeling Group, Harvard University Kelly V. Chance and Thomas Kurosu Harvard/Smithsonian Center for Astrophysics M.J. Pilling and J. Stanton (U. Leeds); A. Guenther, C. Wiedinmyer (NCAR); B. Barletta (UC Irvine)

Outline I.Vegetation representation -AVHRR LAI -MEGAN inventory for biogenic VOCs II.Constraints on East Asian VOC emissions -GOME information -TRACEP information III.Summary

AVHRR Leaf Area Index 1982 – 2000 AVHRR 10 day maximum NDVI 8km monthly LAI 0.5deg monthly LAI Model grid monthly LAI Myneni et al. (1997) Landmap and Climatology T & precip. NPP 0.5deg monthly LAI Model grid monthly LAI +/- 20%

AVHRR Leaf Area Index Validation Buermann et al. (2002) Dust mobilization and dry deposition also sensitive to LAI

AVHRR Leaf Area Index Interannual Variability Buermann et al. (2002) July + August (40-50N) April + May (40-50N)

Modeling the terrestrial biosphere April Sep LAI PAR – direct and diffuse (GMAO) AVHRR LAI Canopy model (Guenther 1995) Altitude Emission Temperature: Instantaneous (G95) 15-day history avg Fixed base emission factors (Guenther 2004) Emissions Courtesy Paul Palmer GEOS3, GEOS4

Model of Emissions of Gas and Aerosols from Nature (MEGAN) INVENTORY Emission rate = AEF × MEF × DEF × HEF Alex Guenther and Christine Wiedinmyer (NCAR) Leaf area Leaf age Light Temperature Canopy attenuation T history World ecoregion map EF by ecoregion AVHRR land cover (plant type fraction)

MEGAN INVENTORY Guenther et al. (manuscript in preparation) Chinese emissions: Compare to Anthro+BB NMVOC emission = 17.4 Tg/yr Global emissions:

BVOC EMISSION INVENTORY MEGAN GEOS3, GEOSS Global isoprene Tg C/yr Latest emission factors AVHRR land map and lai AEF must be computed offline for land use change studies GEIA GEOS1, GEOSS, GEOS3, GEOS4 Global isoprene Tg C/yr Olson (1982) land map More flexibility for land use change studies

RELATING HCHO COLUMNS TO VOC EMISSION VOC i HCHO h (340 nm), OH oxn. k ~ 0.5 h -1 Emission E i smearing, displacement In absence of horizontal wind, mass balance for HCHO column  HCHO : yield y i … but wind smears this local relationship between  HCHO and E i depending on the lifetime of the parent VOC with respect to HCHO production: Local linear relationship between HCHO and E VOC source Distance downwind  HCHO Isoprene  -pinene propane 100 km Courtesy P.I. Palmer (Harvard)

EVALUATING GOME ISOPRENE EMISSION ESTIMATES vs. PROPHET IN SITU FLUX MEASUREMENTS (2001) Also shown are local MEGAN isoperene emission inventory values P.I. Palmer (Harvard), S.N. Pressley and B. Lamb (WSU), A. Guenther and C. Wiedinmyer (NCAR)

GOME HCHO COLUMNS OVER EAST ASIA ( ) Relationship to VOC emissions far more complex than for N. America. Biomass burning, isoprene, anthropogenic VOCs, direct HCHO emission all contribute; need multivariate regression APRJAN FEB MAR MAY JUN JUL AUG SEP OCT NOV DEC

GOME HCHO COLUMNS OVER EAST ASIA ( ) APR MAY JUN JUL AUG SEP

NC CC WC SC VOC CONTRIBUTIONS TO HCHO PRODUCTION IN CHINESE CITIES (JAN-FEB 2001) Ethane0.3 %Benzene0.4 % Propane0.3 %Toluene2.4 % ALK45.1 %Xylene20.2 % Ethene19 %Isoprene8.2 % PRPE43 % B. Barletta (UCI), T.-M. Fu (Harvard) Vehicle-generated xylenes could make a large contribution to HCHO columns NC CC WC SC

Streets inventory for East Asia Klimont et al. [2002] GOME r Uncertainty +/- 130%

VOC / CO emission ratio in Chinese cities Obs data: B. Barletta UC Irvine StreetsETHE/CO 3x too high XYLE/CO 2x too low

Simulation GEOS3 2x East Asia: Streets inventory [2001] including ETHE, XYLE and direct HCHO emission C 2 H 6 : Xiao et al. [2004] CO correction: Heald et al. [2004] NO x correction: Wang et al. [2004b] Anthropogenic seasonality (FF+BF): Streets et al. [2003] Biomass burning seasonality: Duncan et al. [2003] + Heald et al. [2003] MEGAN inventory (AVHRR LAI) ETHE, XYLE, MONX chemistry

C 2 H 4 chemistry Vereecken and Peeters [1999] Orlando et al. [2003]

Aromatics 0.18 per C J. Stanton and M. Pilling Bloss et al. [2004] MCM v3.1  OH = 9.9 h 0.26 per C MCM v3.1  OH = 2.4 h m-xylene toluene High HCHO and GLXY yield from aromatic hydrocarbons also observed by Volkamer et al. [2001]. HCHO underestimated in MCM Xylene removal underestimated in MCM Measurements show rapid SOA formation

TRACEP: Chinese outflow [30-60N, E] z < 2km, [CO] < 400 ppbv OBS Model w/ ETHE, XYLE Model w/o ETHE, XYLE Model only 23% of observation

TRACEP: Chinese outflow [30-60N, E] z < 2km, [CO] < 400 ppbv OBS Model w/ ETHE, XYLE Model ETHE/CO 3x too high HCHO sources independent of ETHE contribute ~50% Model XYLE/CO 3x too high

Direct HCHO sources from transportation? Kolb et al. [2004] Streets emission HCHO / CO 2 = 4 x – 4 x [mole/mole] Mexico City 2 x [mole/mole] Boston 3 x [mole/mole] HCHO (ppb) CO 2 (ppm)

SUMMARY From in-situ measurements: Short-lived anthropogenic VOCs such as alkenes and xylenes contributes > 80% to local HCHO production, and > 25% to HCHO VC Ethene/CO emission may be overestimated by factors of 3-4 in parts of China Xylene/CO emission may be underestimated by factors of Preliminary model and TRACEP comparisons agree with in situ measurements Possibile direct HCHO source independent of ethene emissions In progress: multivariate regression to evaluate relative contribution from different sources

BACKUP

1 x 1 2 x x 5 GOME (launched Apr 1995) Nadir viewing Global coverage in 3 days 320 km x 40 km O 3, NO 2, HCHO, etc Jul 1995 to Dec 2003 SCIAMACHY (launched Mar 2002) Nadir/limb Global coverage in 3 days 60 km x 30 km O 3, NO 2, HCHO, CO, CO 2, CH 4, etc A. Richter, IUP U Bremen OMI (launched Jul 2004) Nadir viewing Global coverage in 1 day 24 km x 13 km O 3, NO 2, HCHO, etc 1 x 1 2 x x 5

Monthly mean LAI (AVHRR/MODIS) MEGAN (isoprene) Canopy model Leaf area Leaf age Temperature history Base factors MODEL BIOSPHERE GEIA Monoterpenes MBO Acetone Methanol GEOS-CHEM Global 3D CTM PAR, T Emissions Global 3-D Modeling Overview Driven by NASA GMAO met data 2x2.5 o resolution/30 vertical levels O 3 -NO x -VOC-aerosol chemistry

INVERTING HCHO COLUMN DATA FOR ISOPRENE EMISSION GOME slant columns (July 96) GOME vertical columns (July 96) Air Mass Factor E ISOPRENE =(1/S)  HCHO GOME isoprene emission inventory GEOS-CHEM CTM GOME/OMI sensitivity HCHO vmr Sigma coordinate validation With HCHO surface air observations with GEIA isoprene emission inventory with GOME isoprene emission inventory Palmer et al. [2001, 2003] E ISOPRENE HCHO column non- isoprene contribution Southeast U.S. slope S Observed HCHO, ppb Model HCHO, ppb

WHAT DRIVES GOME HCHO TEMPORAL VARIABILITY 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

GOME HCHO Column [10 16 molec cm -2 ] Southeast US average 32-38N; W YEAR-TO-YEAR VARIABILITY OF GOME HCHO OVER SOUTHEAST U.S. Amplitude and phase are highly reproducible P. I. Palmer (Harvard)

Biogenic VOC emissions: a pathway of biosphere – atmosphere interaction GHG, aerosols Changing landuse, hydrology Fertilization