Sensitivity of biogenic volatile organic compound emissions to leaf area index and land cover in Beijing
<p>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. F...
Main Authors: | , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2018-07-01
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Series: | Atmospheric Chemistry and Physics |
Online Access: | https://www.atmos-chem-phys.net/18/9583/2018/acp-18-9583-2018.pdf |
Summary: | <p>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 30 m 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.</p> |
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ISSN: | 1680-7316 1680-7324 |