space-based hcho measurements as constraints on voc emissions in asia tzung-may fu, daniel j. jacob...
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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