Ammonia emissions in biomass burning regions: Estimation from satellitederived measurements and comparison with bottom-up inventories
Résumé
Vegetation fires emit large amounts of ammonia in the atmosphere (NH3). Excess NH3 can affect the
environment in many ways: eutrophication of the ecosystem, soil acidification and loss of plant
diversity. Despite the numerous studies achieved in the past decades to better quantify NH3 emissions
from biomass burning (mainly from bottom-up approaches), the uncertainties remain still large. NH3
satellite measurements are now available for a few years and offer the possibility to better assess the
NH3 atmospheric budget, its spatial distribution and long-term trends.
In this presentation we first analyze monthly NH3 total columns (molec cm-2) from IASI on MetOp-A
satellite over four large tropical regions known for their important seasonal fire activity. We next
derive for these regions the monthly NH3 emissions using a simplified box model and perform a topdown
evaluation for NH3 of the most widely used fire emission inventories (GFEDv3.1 and the
GFASv1.2).
We then focus our attention on the NH3 emissions from the intense fires which were devastating
Indonesia in fall 2015. The region of Indonesia is characterized by peat soils, whose burning is thought
to emit large amounts of NH3. To assess the importance of NH3 emissions from peat fires compared to
other biomes, we derive NH3 enhancement ratios (ERs) relative to CO and we compare them to ERs
derived from other biomes in tropical biomass burning regions. We also compare these results to the
ERs reported in the literature.