Validation of ACE-FTS N2O measurements

Year: 2008

Authors: Strong K., Wolff MA., Kerzenmacher TE., Walker KA., Bernath PF., Blumenstock T., B.,Boone C., Catoire V., Coffey M., De Maziere M., Demoulin P., Duchatelet P., Dupuy E., Hannigan J., Hopfner M., Glatthor N., Griffith DWT., Jin JJ., Jones N., Jucks K., Kuellmann H., Kuttippurath J., Lambert A., Mahieu E., McConnell JC., Mellqvist J., Mikuteit S., Murtagh DP ., Notholt J., Piccolo C., Raspollini P., P., Ridolfi M., Robert C., Schneider M., Schrems O., Semeniuk K., Senten C., Stiller GP., Strandberg A., Taylor J., Tetard C., Toohey M., Urban J., Warneke T., Wood S.

Autors Affiliation: Univ Toronto, Dept Phys, Toronto, ON, Canada
Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada
Univ York, Dept Chem, York YO10 5DD, N Yorkshire, England
Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany
Univ Karlsruhe, Inst Meterol & Climate Res, Karlsruhe, Germany
Univ Orleans, CNRS, Lab Phys & Chim Environm, Orleans, France
Natl Ctr Atmospher Res, Boulder, CO 80307 USA
Belgian Inst Space Aeron, Brussels, Belgium
Univ Liege, Inst Astrophys & Geophys, Liege, Belgium
Univ Wollongong, Sch Chem, Wollongong, NSW, Australia
York Univ, Dept Earth & Space Sci & Engn, Toronto, ON M3J 2R7, Canada
Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
Univ Bremen, Inst Environm Phys, Bremen, Germany
CALTECH, Jet Prop Lab, Pasadena, CA USA
Chalmers, Dept Radio & Space Sci, S-41296 Gothenburg, Sweden
Univ Oxford, Dept Phys, Oxford, England
Natl Res Ctr, Inst Appl Phys Nello Carrara, Florence, Italy
Univ Bologna, Dipartimento Chim Fis & Inorgan, I-40136 Bologna, Italy
Alfred Wegener Inst Polar & Marine Res, D-2850 Bremerhaven, Germany
Univ Sci & Technol Lille, Opt Atmospher Lab, Villeneuve Dascq, France
Natl Inst Water & Atmospher Res Ltd, Lauder, New Zealand

Abstract: The Atmospheric Chemistry Experiment (ACE), also known as SCISAT, was launched on 12 August 2003, carrying two instruments that measure vertical profiles of atmospheric constituents using the solar occultation technique. One of these instruments, the ACE Fourier Transform Spectrometer (ACE-FTS), is measuring volume mixing ratio (VMR) profiles of nitrous oxide (N2O) from the upper troposphere to the lower mesosphere at a vertical resolution of about 3-4 km. In this study, the quality of the ACE-FTS version 2.2 N2O data is assessed through comparisons with coincident measurements made by other satellite, balloon-borne, aircraft, and ground-based instruments. These consist of vertical profile comparisons with the SMR, MLS, and MIPAS satellite instruments, multiple aircraft flights of ASUR, and single balloon flights of SPIRALE and FIRS-2, and partial column comparisons with a network of ground-based Fourier Transform InfraRed spectrometers (FTIRs). Between 6 and 30 km, the mean absolute differences for the satellite comparisons lie between -42 ppbv and +17 ppbv, with most within +/- 20 ppbv. This corresponds to relative deviations from the mean that are within +/- 15%, except for comparisons with MIPAS near 30 km, for which they are as large as 22.5%. Between 18 and 30 km, the mean absolute differences for the satellite comparisons are generally within +/- 10 ppbv. From 30 to 60 km, the mean absolute differences are within +/- 4 ppbv, and are mostly between -2 and +1 ppbv. Given the small N2O VMR in this region, the relative deviations from the mean are therefore large at these altitudes, with most suggesting a negative bias in the ACE-FTS data between 30 and 50 km. In the comparisons with the FTIRs, the mean relative differences between the ACE-FTS and FTIR partial columns (which cover a mean altitude range of 14 to 27 km) are within +/- 5.6% for eleven of the twelve contributing stations. This mean relative difference is negative at ten stations, suggesting a small negative bias in the ACE-FTS partial columns over the altitude regions compared. Excellent correlation (R=0.964) is observed between the ACE-FTS and FTIR partial columns, with a slope of 1.01 and an intercept of -0.20 on the line fitted to the data.

Journal/Review: ATMOSPHERIC CHEMISTRY AND PHYSICS (PRINT)

Volume: 8 (16)      Pages from: 4759  to: 4786

More Information: Funding for the ACE mission was provided primarily by the Canadian Space Agency (CSA) and the Natural Sciences and Engineering Research Council (NSERC) of Canada. This work was also supported by a grant from the CSA.r Odin is a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the CSA, the Centre National d’Etudes Spatiales (CNES) in France and the National Technology Agency of Finland (Tekes).r Thanks to B. Bojkov of the Aura Validation Data Center (AVDC) and the Aura-MLS Data Distribution Team for access to the Aura-MLS dataset (see http://avdc.gsfc.nasa.gov). Work at the Jet Propulsion Laboratory, California Institute of Technology, is carried out under a contract with the National Aeronautics and Space Administration (NASA).r The IMK-IAA team thanks the European Space Agency (ESA) for providing MIPAS level 1 and 2 datasets. We would also like to acknowledge the following people for their work on the MIPAS data relevant to this validation study: T. von Clarmann, U. Grabowski, S. Kellmann, M. Kiefer, A. Linden, M. Milz, and T. Steck from IMK, and B. Funke and M. Lopez-Puertas from IAA.r The ASUR group would like to acknowledge help and support from H. Bremer, A. Kleinbohl and G. Naeveke.r The SPIRALE balloon measurements could only be performed thanks to the technical team (L. Pomathiod, B. Gaubicher, G. Jannet); the flight was funded by ESA and the French space agency CNES for the Envisat validation project …
KeyWords: GROUND-BASED FTIR; MOLECULAR SPECTROSCOPIC DATABASE; CRYOGENIC INFRARED SPECTROMETERS; ATMOSPHERE RESEARCH SATELLITE; VERTICAL COLUMN ABUNDANCES; IR SOLAR SPECTRA; NITROUS-OXIDE; MESOSPHERIC SOUNDER; LOWER STRATOSPHERE; ERROR ANALYSIS
DOI: 10.5194/acp-8-4759-2008