Nav: Home

First detection of ammonia in the upper troposphere

December 05, 2016

Population is growing, climate is warming - hence, emission of ammonia (NH3) trace gas from e.g. agriculture will increase worldwide. Recently, scientists of Karlsruhe Institute of Technology (KIT) for the first time detected NH3 in the upper troposphere. Together with researchers from Colorado/USA and Mexico, they analyzed satellite measurements by the MIPAS infrared spectrometer and found increased amounts of NH3 between 12 and 15 km height in the area of the Asian monsoon. This suggests that the gas is responsible for the formation of aerosols, smallest particles that might contribute to cloud formation. The researchers present their work in the Atmospheric Chemistry and Physics journal. (DOI: 10.5194/acp-16-14357-2016)

Ammonia, a chemical compound of nitrogen and hydrogen, mainly originates from agricultural processes, in particular from lifestock farming and fertilization. Wide application of ammonia as a basic substance of fertilizers became possible by the development of artificial ammonia synthesis in Karlsruhe more than 100 years ago. Today, highest ammonia emissions are encountered in North India and Southeast China. Due to population growth and global warming, global ammonia emissions are expected to increase strongly in the future. Gaseous ammonia reacts with acids, such as sulfuric acid or nitric acid, to the corresponding ammonium salts. However, ammonia does not only pollute the ecosystems. Particles of ammonium salts can attach to each other and form aerosol particles acting as condensation nuclei in cloud formation. Such aerosols of anthropogenic origin have a cooling effect in the atmosphere and might compensate part of the anthropogenic greenhouse effect.

In this connection, it is important to determine vertical distribution of atmospheric ammonia. Concentrations of ammonia in the middle and upper troposphere, the bottom layer of the atmosphere, have hardly been studied so far. Now, researchers of the Atmospheric Trace Gases and Remote Sensing Division of KIT's Institute for Meteorology and Climate Research (IMK-ASF) as well as of the University of Colorado at Boulder and the Universidad Nacional Autónoma de México for the first time detected ammonia in the upper troposphere. They evaluated measurements made by the MIPAS infrared spectrometer on the European environmental satellite ENVISAT from 2002 to 2012. MIPAS, an instrument designed by KIT, recorded highly resolved spectra in the middle infrared range, from which gases can be identified clearly. Every gas emits specific infrared radiation.

The scientists calculated the average of three-month measurements in areas of ten degrees longitude and ten degrees latitude each. At 12 to 15 km height, in the area of the Asian monsoon, they found an increased concentration of ammonia of up to 33 pptv (33 NH3 molecules per trillion air molecules). Similarly high concentrations were measured in no other season and no other region. "Observations show that ammonia is not washed out completely when air ascends in monsoon circulation. Hence, it enters the upper troposphere from the boundary layer close to the ground, where the gas occurs at relatively high concentrations," Dr. Michael Höpfner, Head of the Remote Sensing Using Aircraft and Balloons Group of IMK-ASF. "It is therefore assumed that part of the Asian tropopause aerosol layer consists of ammonium salts."

Outside of the area of the Asian monsoon, concentrations of ammonia in the upper troposphere were found to be below the detection limit of a few pptv. This finding can contribute to refining global models. As far as the Asian monsoon is concerned, a large measurement campaign with the GLORIA instrument is planned in 2017. GLORIA is a novel type of infrared camera that decomposes the thermal radiation emitted by atmospheric gases into its spectral colors and, hence, yields ammonia concentration results near the tropopause, the boundary layer between the troposphere and the above stratosphere, of higher temporal and spatial - horizontal and vertical - resolution.
Michael Höpfner, Rainer Volkamer, Udo Grabowski, Michel Grutter, Johannes Orphal, Gabriele Stiller, Thomas von Clarmann, and Gerald Wetzel: First detection of ammonia (NH3) in the Asian summer monsoon upper troposphere. Atmospheric Chemistry and Physics, 2016. DOI: 10.5194/acp-16-14357-2016

For further information, please contact: Margarete Lehné, Press Officer, Phone: +49 721 608-4 8121, Fax: +49 721 608-4 3658, Email:

More about the KIT Climate and Environment Center:

Karlsruhe Institute of Technology (KIT) pools its three core tasks of research, higher education, and innovation in a mission. With about 9,300 employees and 25,000 students, KIT is one of the big institutions of research and higher education in natural sciences and engineering in Europe.

KIT - The Research University in the Helmholtz Association

Since 2010, the KIT has been certified as a family-friendly university.This press release is available on the internet at

Karlsruher Institut für Technologie (KIT)

Related Climate Articles:

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
How trees could save the climate
Around 0.9 billion hectares of land worldwide would be suitable for reforestation, which could ultimately capture two thirds of human-made carbon emissions.
Climate undermined by lobbying
For all the evidence that the benefits of reducing greenhouse gases outweigh the costs of regulation, disturbingly few domestic climate change policies have been enacted around the world so far.
Climate education for kids increases climate concerns for parents
A new study from North Carolina State University finds that educating children about climate change increases their parents' concerns about climate change.
Inclusion of a crop model in a climate model to promote climate modeling
A new crop-climate model provides a good tool to investigate the relationship between crop development and climate change for global change studies.
More Climate News and Climate Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...