SPACE-BASED HCHO MEASUREMENTS SPACE-BASED HCHO MEASUREMENTS AS CONSTRAINTS ON VOC EMISSIONS IN ASIAAS CONSTRAINTS ON VOC EMISSIONS IN ASIA

Tzung-May Fu, Daniel J. JacobHarvard University

Kelly V. ChanceHarvard SAO/CFA

Work supported by NASAAtmospheric Chemistry Modeling and Analysis Program

Barbara Barletta, Donald BlakeUniversity of California at Irvine

Paul I. PalmerUniversity of Leeds

Anthropogenic 40 TgStreets et al. [2003]

Biomass burning 12 TgStreets et al. [2003]

Biogenic 80 TgMEGAN

State-of-the-sciences inventories

CTM (GEOS-Chem) GOME

Spatial variation

Seasonal variation

MEGAN GOME

Over N Am GOME HCHO dominated by biogenic isoprene

Well captured by MEGAN

Palmer et al. [2001, 2003, 2005], Abbot et al. [2003]

METHODSMETHODS

Relationship to VOC emissions far more complex than for N. America; biomass burning, isoprene, anthropogenic VOCs, direct HCHO emission all contribute

GOME HCHO MONTHLY COLUMNS OVER ASIA (1996-2001)GOME HCHO MONTHLY COLUMNS OVER ASIA (1996-2001)

Month Change 95% C. I.

DEC +25% +12~37%

JAN +32% +17~47%

FEB +20% +1~33%

Excess winter GOME HCHO due to Excess winter GOME HCHO due to Chinese anthropogenic short-lived VOCsChinese anthropogenic short-lived VOCs

Percent change to Streets et al. [2003] emissions

Chinese grids w/ GOME > 0

Reduced major axis linear regression

CHINESE URBAN CHINESE URBAN MEASUREMENTSMEASUREMENTS

83HC

VOC

83HC

VOC

E

E

Urban air sampled in 43 Chinese cities in Jan and Feb 2001 [Barletta et al., 2005]

LocalInventory EVOC / EC3H8

OBS [VOC] / [C3H8]Inventory underestimates

pentane, ethyne, xylenes

underestimates vehicular emission

9% HCHO

Enhanced primary HCHO emission from vehicles

+10~60% HCHO

HCHO SEASONAL VARIATIONHCHO SEASONAL VARIATION

GOMEGEOS-Chem

BiogenicBiomass x 2Anthropogenic x 2Model bkgd

HC

HO

ver

tica

l co

lum

n [

1016

mo

lec/

cm2]

GOME – Model background = 1 x biogenic + 2 biomass

r2 = 0.80 ~ 0.93

MEGAN31 TgC

GOME27 TgC

GEIA37 TgC

BIOGENIC ISOPRENE EMISSIONBIOGENIC ISOPRENE EMISSION

Higher emission by the deciduous broadleaf forests in China

Lower emission by the evergreen broadleaf forests in SE Asia & Indonesia

Scaling factors GOME vs MEGAN

Streets et al.

0.26 TgCGOME1.7 TgC

BIOMASS BURMING HCHO EMISSIONBIOMASS BURMING HCHO EMISSION

Scaling factors GOME vs Streets

3x EF

30~70% residual

SUMMARYSUMMARY

Model 132 Tg/yr GOME 137 Tg/yr

• Spatial and seasonal variation of HCHO column can be use to constrain anthropogenic, biomass burning, and biogenic VOC emissions

• Previously unrecognized burning associated with winter wheat harvesting in June over North China Plains, equivalent to 30% to 70% percent of crop residual burned in field

Total NMVOC