Lieven Clarisse and Martin Van Damme from ULB have reported on their findings in Nature this week and they are reproduced below on our Science Blog.
For over 10 years, the IASI instrument on board the three successive Metop satellites have been providing scientists with global data on various atmospheric components, including ammonia.
Because of its role in the formation of particulate matter, atmospheric ammonia is a key driver of air quality, with major impacts on human health and life expectancy. Excess ammonia also affects the entire biosphere through acidification and eutrophication of ecosystems and, indirectly, the climate.
(a) Oversampled overage distribution of ammonia (molecules/cm2) over Northern and Central America using almost a decade of IASI satellite measurements. Hotspots are identified with black circles which size quantifies the satellite-derived emission flux (kg/s). Large source regions are indicated with white rectangle. (b) Ammonia distribution (molecules/cm2) overlaid on visible imagery in Torreon (Mexico), which is a typical example of a cluster of agricultural point sources. (c) Closer view (delineated by a white square in panel b) to one of the agricultural feedlots responsible for the large amount of ammonia emitted. Map data from Google Earth, CNES/Airbus, DigitalGlobe and Landsat/Copernicus. © Martin Van Damme and Lieven Clarisse / ULB
Anthropogenic NH3 emissions originate mainly from agricultural, domestic and industrial activities, but both the total budget and the partitioning between the sources are highly uncertain, on all spatial scales.
These aerial photographs show (left) a cluster of cattle feedlots (Tascosa Feedyard in Texas, US) and their associated waste lagoon in the centre. The photograph on the right shows a synthetic fertilizer production complex in Ferghana (Uzbekistan). Both are examples of industrial point sources that release prodigious amounts of NH3. Until now the importance of these emissions has been drastically underestimated.
© Google Earth, Landsat/Copernicus
Using almost a decade of IASI measurements, researchers from ULB have generated a high-resolution map (~1km²) of the global atmospheric distribution of ammonia. From it, they identify, categorise and quantify over 200 hotspots that could be traced back to either a single or a cluster of agricultural and industrial point sources. One natural hotspot was also determined.
Global oversampled overage distribution of ammonia (molecules/cm2) using almost a decade of IASI satellite measurements. Hotspots are identified with black circles which size quantifies the satellite-derived emission flux (kg/s). Large source regions are indicated with white rectangle. © Martin Van Damme and Lieven Clarisse / ULB
This research has shown that emissions from such sources were drastically underestimated in the current bottom-up inventories, with 2/3 of the identified point sources completely absent.
The IASI era (2007+) also allows for observing changes in human activities. Opening and closures of industrial sites were identified in Eastern Europe and China, as well as agriculture in transition in South America.
Ammonia distribution observed by IASI over Europe, northern Africa and Middle East. © Martin Van Damme and Lieven Clarisse / ULB; © Google Earth, Landsat/Copernicus
These findings suggest the need to completely revisit the emission inventories for anthropogenic NH3 sources, and to account for their rapid evolution in time. This is critically needed for assessing the health and environmental impact of NH3 and implementing suitable nitrogen management strategies.
Ammonia emission fluxes calculated based on almost a decade of IASI measurements.
© Martin Van Damme and Lieven Clarisse / ULB; © Google Earth, Landsat/Copernicus
Federico Fierli, Senior Trainer within the User Support and Climate Service Division at EUMETSAT had this to add:
Measuring NH3 through satellite observations is a very important achievement, especially as the NH3 produced by agriculture and farming is highly volatile and difficult to measure. There are in-situ networks available, however these do not provide global coverage and measurements are achieved using different techniques.
NH3 has an acidification effect on soil and water and is therefore considered harmful. There are some agreements in place to control and reduce these emissions with abatement techniques, and the use of satellites provide a unique time and spatial coverage that makes it possible to control the effect of the emission abatement strategy.
Observing the atmosphere with the IASI instruments on board the polar-orbiting Metop satellites, is a strategy employed by EUMETSAT that will allow for the long-term monitoring of NH3.
Read the full article here.
Reference: Van Damme, M., Clarisse, L., Whitburn, S., Hadji-Lazaro, J., Hurtmans, D., Clerbaux, C., Coheur, P.-F. Industrial and agricultural ammonia point sources exposed. Nature, (2018).
The operational generation of NH3 products based on the algorithms described in this article will be done at EUMETSAT Headquarter on behalf of the EUMETSAT Satellite Application Facility on Atmospheric Composition Monitoring (AC SAF). http://ac-saf.eumetsat.int.