An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements
Item
Title (Dublin Core)
An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements
Description (Dublin Core)
Global distributions of atmospheric ammonia (NH<sub>3</sub>) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH<sub>3</sub> 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 NH<sub>3</sub> 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-NH<sub>3</sub> product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH<sub>3</sub> 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 NH<sub>3</sub> 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 NH<sub>3</sub> levels, whereas correlations are lower at sites with low atmospheric NH<sub>3</sub> levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (<i>N</i><sub>obs</sub> = 547) give a mean relative difference of −32.4 ± (56.3) %, a correlation <i>r</i> 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 %).
Creator (Dublin Core)
Dammers, Enrico
Palm, Mathias
Damme, Martin
Vigouroux, Corinne
Smale, Dan
Conway, Stephanie
Toon, Geoffrey C.
Jones, Nicholas
Nussbaumer, Eric
Warneke, Thorsten
Petri, Christof
Clarisse, Lieven
Clerbaux, Cathy
Hermans, Christian
Lutsch, Erik
Strong, Kim
Hannigan, James W.
Nakajima, Hideaki
Morino, Isamu
Herrera, Beatriz
Stremme, Wolfgang
Grutter, Michel
Schaap, Martijn
Wichink Kruit, Roy J.
Notholt, Justus
Coheur, Pierre-F.
Erisman, Jan Willem
Date (Dublin Core)
2018-09-19
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-16-10351-2016
https://acp.copernicus.org/articles/16/10351/2016/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
