Validation of ACE-FTS N2O measurements K. Strong1, M. A. Wolff1, T. E. Kerzenmacher1, K. A. Walker1,2, P. F. Bernath2,3, T. Blumenstock4, C. Boone2, V. Catoire5, M. Coffey6, M. De Mazière7, P. Demoulin8, P. Duchatelet8, E. Dupuy2, J. Hannigan6, M. Höpfner4, N. Glatthor4, D. W. T. Griffith9, J. J. Jin10, N. Jones9, K. Jucks11, H. Kuellmann12, J. Kuttippurath12,*, A. Lambert13, E. Mahieu8, J. C. McConnell10, J. Mellqvist14, S. Mikuteit4, D. P. Murtagh14, J. Notholt12, C. Piccolo15, P. Raspollini16, M. Ridolfi17, C. Robert5, M. Schneider4, O. Schrems18, K. Semeniuk10, C. Senten7, G. P. Stiller4, A. Strandberg14, J. Taylor1, C. Tétard19, M. Toohey1, J. Urban14, T. Warneke12, and S. Wood20 1Department of Physics, University of Toronto, Toronto, Ontario, Canada 2Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada 3Department of Chemistry, University of York, York, UK 4Forschungszentrum Karlsruhe and University of Karlsruhe, Institute for Meteorology and Climate Research (IMK), Karlsruhe, Germany 5Laboratoire de Physique et Chimie de L'Environment CNRS – Université d'Orléans, Orléans, France 6National Center for Atmospheric Research, Boulder, CO, USA 7Belgian Institute for Space Aeronomy, Brussels, Belgium 8Institute of Astrophysics and Geophysics, University of Liège, Liège, Belgium 9School of Chemistry, University of Wollongong, Wollongong, Australia 10Department of Earth and Space Science and Engineering, York University, Toronto, Ontario, Canada 11Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA 12Institute for Environmental Physics, University of Bremen, Bremen, Germany 13Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA 14Department of Radio and Space Science, Chalmers University of Technology, Gothenburg, Sweden 15Department of Physics, University of Oxford, Oxford, UK 16Institute of Applied Physics "Nello Carrara", National Research Center, Firenze, Italy 17Dipartimento di Chimica Fisica e Inorganica, Università di Bologna, Bologna, Italy 18Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany 19Laboratoire d'Optique Atmosphérique, Université des sciences et technologies de Lille, Villeneuve d'Ascq, France 20National Institute of Water and Atmospheric Research Ltd., Lauder, New Zealand *now at: LMD/CNRS Ecole Polytechnique, Palaiseau Cedex, France
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.
Citation: Strong, K., Wolff, M. A., Kerzenmacher, T. E., Walker, K. A., Bernath, P. F., Blumenstock, T., Boone, C., Catoire, V., Coffey, M., De Mazière, M., Demoulin, P., Duchatelet, P., Dupuy, E., Hannigan, J., Höpfner, M., Glatthor, N., Griffith, D. W. T., Jin, J. J., Jones, N., Jucks, K., Kuellmann, H., Kuttippurath, J., Lambert, A., Mahieu, E., McConnell, J. C., Mellqvist, J., Mikuteit, S., Murtagh, D. P., Notholt, J., Piccolo, C., Raspollini, P., Ridolfi, M., Robert, C., Schneider, M., Schrems, O., Semeniuk, K., Senten, C., Stiller, G. P., Strandberg, A., Taylor, J., Tétard, C., Toohey, M., Urban, J., Warneke, T., and Wood, S.: Validation of ACE-FTS N2O measurements, Atmos. Chem. Phys., 8, 4759-4786, doi:10.5194/acp-8-4759-2008, 2008.