Past and present-day biogenic volatile organic compound emissions in East Asia

Abstract

Biogenic volatile organic carbon (VOC) emissions from vegetation in East Asia are estimated for two contrasting land-cover scenarios: near present-day conditions derived from satellite data and pre-disturbed land-cover based on climatological parameters and plant functional type. Hourly fluxes of isoprene and monoterpenes are calculated on a grid of 60 km  60 km cells covering much of East Asia using meteorological conditions derived from a 12-month simulation of the region using regional climate model, monthly leaf area indexes, and the Guenther et al. (J. Geophys. Res. 101 (1995) 1345) ecosystem-dependent emission factors. Total present-day isoprene emissions are estimated at approximately 12 Tg C yr À1 and monoterpene emissions at 6 Tg C yr À1 . These emissions are approximately 5.4 and 4 Tg C yr À1 lower than the estimated pre-disturbed emissions of isoprene and monoterpenes, respectively, largely due to the conversion of forested land to cropland. ORVOC emission estimates for the present-day scenario, obtained by assuming a constant ORVOC emission factor for all ecosystems, are slightly higher in magnitude than isoprene emissions. Present-day totals of combined biogenic and anthropogenic VOC emissions are generally larger than biogenic VOC emissions in the pre-disturbed scenario, indicating that human activities have led to a net increase in the atmospheric source of VOC in East Asia. r

Investigation of NO<sub>x</sub> emissions and NO<sub>x</sub>-related chemistry in East Asia using CMAQ-predicted and GOME-derived NO<sub>2</sub> columns

“…Furthermore, Fu et al (2007) recently estimated an even lower isoprene flux of 10.8 Tg yr −1 over East Asia from an inversion analysis of the GOME-retrieved HCHO columns. Overall, the isoprene flux used in this study might be approximately 1.5 to 2 times larger than those reported by Steiner et al (2002) and Fu et al (2007). The CMAQ-simulated HCHO (mostly, isoprene-derived in summer) columns were also compared with the GOME-retrieved HCHO columns for the summer episode (not shown).…”

“…edu/EMISSION DATA/index.htm). Streets et al (2003) provided detailed information on the emission inventory (hereafter, labeled the ACE-ASIA inventory) used in this study. The ACE-ASIA emission inventory included NO x emissions from fossil fuels and bio-fuel combustion as well as biomass (vegetation) burning in East Asia.…”

“…In this inventory, an isoprene flux of 20.0 Tg yr −1 over East Asia was estimated. However, Steiner et al (2002) estimated an isoprene flux of only 13.6 Tg yr −1 over East Asia, using the land-cover conditions derived from the AVHRR satellite. Furthermore, Fu et al (2007) recently estimated an even lower isoprene flux of 10.8 Tg yr −1 over East Asia from an inversion analysis of the GOME-retrieved HCHO columns.…”

“…Several studies reported that NO x emissions from fossil fuel combustion in the United States and in East Asia are almost aseasonal (e.g., Streets et al, 2003;Jaeglé et al, 2005). Therefore, several 3-D global and regional CTM studies were carried out with constant (aseasonal) NO x emission fluxes, and were then compared with the GOME-and/or SCIAMACHY-derived NO 2 columns (e.g., van Noije et al, 2005;Uno et al, 2007).…”

“…There are several NO x emission inventories in China available for 2001 including i) ACE-ASIA/TRACE-P inventory (Streets et al, 2003), ii) REAS , iii) EDGAR (Emission Database for Global Atmospheric Research) (Olivier et al, 1999(Olivier et al, , 2002, and iv) GEIA. Here, the ACE-ASIA and REAS inventories were used for a comparison study of the NO x emission fluxes from China.…”