Space-based observations of fire NO<sub>x</sub> emission coefficients: a global biome-scale comparison
Biomass burning represents both a significant and highly variable source of NO<sub>x</sub> to the atmosphere. This variability stems from both the episodic nature of fires, and from fire conditions such as the modified combustion efficiency of the fire, the nitrogen content of the fuel a...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/14/2509/2014/acp-14-2509-2014.pdf |
| Summary: | Biomass burning represents both a significant and highly variable source of
NO<sub>x</sub> to the atmosphere. This variability stems from both the episodic
nature of fires, and from fire conditions such as the modified combustion
efficiency of the fire, the nitrogen content of the fuel and possibly other
factors that have not been identified or evaluated by comparison with
observations. Satellite instruments offer an opportunity to observe
emissions from wildfires, providing a large suite of measurements which
allow us to study mean behavior and variability on the regional scale in a
statistically rigorous manner. Here we use space-based measurements of fire
radiative power from the Moderate Resolution Imaging Spectroradiometer in
combination with NO<sub>2</sub> tropospheric column densities from the Ozone
Monitoring Instrument to measure mean emission coefficients (ECs in g NO MJ<sup>−1</sup>)
from fires for global biomes, and across a wide range of
smaller-scale ecoregions, defined as spatially-distinct clusters of fires
with similar fuel type. Mean ECs for all biomes fall between 0.250–0.362 g NO MJ<sup>−1</sup>,
a range that is smaller than found in previous studies of
biome-scale emission factors. The majority of ecoregion ECs fall within or
near this range, implying that under most conditions, mean fire emissions of
NO<sub>x</sub> per unit energy are similar between different regions regardless of
fuel type or spatial variability. In contrast to these similarities, we find
that about 24% of individual ecoregion ECs deviate significantly (with
95% confidence) from the mean EC for the associated biome, and a similar
number of ecoregion ECs falls outside the range of all mean biome ECs,
implying that there are some regions where fuel type-specific global
emission parameterizations fail to capture local fire NO<sub>x</sub> emissions. |
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| ISSN: | 1680-7316 1680-7324 |