Publications

Wang, H; Wu, QZ; Liu, HJ; Wang, YL; Cheng, HQ; Wang, RR; Wang, LN; Xiao, H; Yang, XC (2018). Sensitivity of biogenic volatile organic compound emissions to leaf area index and land cover in Beijing. ATMOSPHERIC CHEMISTRY AND PHYSICS, 18(13), 9583-9596.

Abstract
The Beijing area has suffered from severe air pollution in recent years, including ozone pollution in the summer. In addition to the anthropogenic emissions inventory, understanding local ozone pollution requires a reliable biogenic volatile organic compound (BVOC) emission inventory. Forest coverage rose from 20.6 to 35.8% from 1998 to 2013 in Beijing according to the National Forest Resource Survey (NFRS), and accurate representations of land cover for recent years is crucial for estimating BVOC emissions and their impacts on air quality. In this study, we established a high-resolution BVOC emission inventory in Beijing using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) v2.1 with three independent leaf area index (LAI) products and three independent land cover products. Various combinations of the Global LAnd Surface Satellite (GLASS), Moderate-Resolution Imaging Spectroradiometer (MODIS) MCD15, and GEOland (GEO) v2 LAI datasets and the Finer Resolution Observation and Monitoring of Global Land Cover (FROM-GLC), MODIS MCD12Q1 plant functional type (PFT) products, and Climate Change Initiative Land Cover (CCI LC) products are used in five model sensitivity experiments (E1-E5), and the experiment using the FROM-GLC with the highest spatial resolution of 30m and GLASS LAI products was treated as the baseline. These sensitivity calculations were driven by hourly, 3 km meteorological fields from the Weather Research and Forecasting (WRF) model. The following results were obtained: (1) according to the baseline estimate, the total amount of BVOC emissions is 75.9 Gg for the Beijing area, and isoprene, monoterpenes, sesquiterpenes and other VOCs account for 37.6, 14.6, 1.8 and 46% of the total, respectively. Approximately three-quarters of BVOC emissions occur in the summer. (2) According to the sensitivity experiments, the LAI input does not significantly affect the BVOC emissions. Using MODIS MCD15Q1 and GEO v2 LAI led to slight declines of 2.6 and 1.4 %, respectively, of BVOC emissions in the same area. (3) The spatial distribution of PFTs from different inputs strongly influenced the spatial distribution of BVOC emissions. Furthermore, the cross-walking table for converting land cover classes to PFTs also has a strong impact on BVOC emissions; the sensitivity experiments showed that the estimate of BVOC emissions by CCI LC ranged from 42.1 to 70.2 Gg depending on the cross-walking table used.

DOI:
10.5194/acp-18-9583-2018

ISSN:
1680-7316