Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 16, 10351-10368, 2016
https://doi.org/10.5194/acp-16-10351-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
16 Aug 2016
An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements
Enrico Dammers1, Mathias Palm2, Martin Van Damme1,3, Corinne Vigouroux4, Dan Smale5, Stephanie Conway6, Geoffrey C. Toon7, Nicholas Jones8, Eric Nussbaumer9, Thorsten Warneke2, Christof Petri2, Lieven Clarisse3, Cathy Clerbaux3, Christian Hermans4, Erik Lutsch6, Kim Strong6, James W. Hannigan9, Hideaki Nakajima10, Isamu Morino11, Beatriz Herrera12, Wolfgang Stremme12, Michel Grutter12, Martijn Schaap13, Roy J. Wichink Kruit14, Justus Notholt2, Pierre-F. Coheur3, and Jan Willem Erisman1,15 1Cluster Earth and Climate, Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
2Institut für Umweltphysik, University of Bremen, Bremen, Germany
3Spectroscopie de l'Atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), Brussels, Belgium
4Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
5National Institute of Water and Atmosphere, Lauder, New Zealand
6University of Toronto, Toronto, Ontario, Canada
7Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California USA
8Centre for Atmospheric Chemistry, University of Wollongong, Wollongong, Australia
9NCAR, Boulder, Colorado, USA
10Atmospheric Environment Division, National Institute for Environmental Studies (NIES), Tsukuba, Japan
11National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
12Centro de Ciencias de la Atmósfera, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
13TNO Built Environment and Geosciences, Department of Air Quality and Climate, Utrecht, the Netherlands
14National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
15Louis Bolk Institute, Driebergen, the Netherlands
Abstract. Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs = 547) give a mean relative difference of −32.4 ± (56.3) %, a correlation r of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (−50 to +100 %).

Citation: Dammers, E., Palm, M., Van Damme, M., Vigouroux, C., Smale, D., Conway, S., Toon, G. C., Jones, N., Nussbaumer, E., Warneke, T., Petri, C., Clarisse, L., Clerbaux, C., Hermans, C., Lutsch, E., Strong, K., Hannigan, J. W., Nakajima, H., Morino, I., Herrera, B., Stremme, W., Grutter, M., Schaap, M., Wichink Kruit, R. J., Notholt, J., Coheur, P.-F., and Erisman, J. W.: An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements, Atmos. Chem. Phys., 16, 10351-10368, https://doi.org/10.5194/acp-16-10351-2016, 2016.
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Short summary
Atmospheric ammonia (NH3) measured by the IASI satellite instrument is compared to observations from ground-based FTIR instruments. The seasonal cycles of NH3 in both datasets are consistent for most sites. Correlations are found to be high at sites with considerable NH3 levels, whereas correlations are lower at sites with low NH3 levels close to the detection limit of the IASI instrument. The study's results further indicate that the IASI-NH3 product performs better than earlier estimates.
Atmospheric ammonia (NH3) measured by the IASI satellite instrument is compared to observations...
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