ESTIMATION OF BVOC EMISSIONS IN GUANGZHOU AND ITS SPATIAL-TEMPORAL VARIATIONS: PRELIMINARY RESULTS FROM GLOBEIS
Biogenic VOC emissions greatly exceed anthropogenic emissions and are regarded as significant precursors to secondary organic aerosol (SOA) and ozone. Using the Global Biosphere Emission and Interactions System (GloBEIS) model, 1 × 1 km gridded and hourly BVOC emissions in Guangzhou were estimated for the year of 2012. This study used satellite-retrieved land cover data, cloud product and leaf area index (LAI), observed meteorological data and local emission rates for land cover types in South China. The result show that the total BVOC emission in Guangzhou, 2012 was 4.39 kt and the average area emission was 5.93 t/(km 2⋅a), of which isoprene contributed about 55.7% (2.44 kt)), monoterpenes about 11.9% (0.52 kt) and OVOC about 32.4% (1.42 kt). Emission factors of land cover types and correction parameters including LAI, wind speed and relative humidity have great effects on the estimation results of the model. BVOC emissions in Guangzhou exhibit a marked monthly and seasonal pattern with the peak emission in July to August and the lowest emission in January and are mainly distributed in the east-western of Conghua, the north of Zengcheng and the border of Huadu and Conghua, mostly covered by evergreen broadleaf forest with high emission factor, while areas of BVOC emission below 50 kg/(km 2⋅a) are distributed in highly urbanized areas like Tianhe, Yuexiu, Liwan and Haizhu district.