We use a continuous six-year record (1996-2001) of GOME satellite measurements of formaldehyde (HCHO) columns over East and South Asia to improve regional emission estimates of reactive non-methane volatile organic compounds (NMVOCs), including isoprene, alkenes, HCHO, and xylenes.

In the figure above, mean monthly HCHO observations (left panels) are compared to simulated HCHO columns from the GEOS-Chem chemical transport model (right panels) using state-of-science, bottom-up emission inventories from Streets et al. [2003a] for anthropogenic and biomass burning emissions, and Guenther et al. [2006] for biogenic emissions (MEGAN). Model results are sampled between 09:00 and 12:00 local time. GOME observations are at about 10:30 local time.

We find that wintertime GOME observations can diagnose anthropogenic reactive NMVOC emissions from China, leading to an estimate 25% higher than Streets et al. [2003a]. We attribute the difference to vehicular emissions. The biomass burning source for East and South Asia is almost 5 times the estimate of Streets et al. [2003a]. GOME reveals a large source from agricultural burning in the North China Plain in June missing from current inventories. This source may reflect a recent trend toward in-field burning of crop residues as the need for biofuels diminishes. Biogenic isoprene emission in East and South Asia derived from GOME is 56 Tg yr^-1, similar to 52 Tg yr^-1 from MEGAN. We find however that MEGAN underestimates emissions in China and overestimates emissions in the tropics. The higher Chinese biogenic and biomass burning emissions revealed by GOME have important implications for ozone pollution. We find 5 to 20 ppb seasonal increases in surface ozone in GEOS-Chem for central and northern China when using GOME-derived vs. bottom-up emissions.  A full description of this work is given in Fu et al. [2007] .