The Atmospheric Chemistry Experiment (ACE) is a mission designed to study the atmospheric chemistry and dynamics that affect ozone distribution in the upper troposphere and stratosphere. It was launched on 12 August 2003 on board the Canadian SCISAT satellite into a polar (74° inclination) Low Earth Orbit (LEO) at an altitude of approximately 650 km above the Earth’s surface. This orbit is most useful for allowing a full Earth coverage that includes tropical, mid-latitude and polar regions.
The ACE payload is comprised of two instruments: the ACE Fourier Transform Spectrometer (ACE-FTS) and Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (MAESTRO). ACE-FTS operates in the infrared (IR) from 2.3 to 13.3 µm. MAESTRO is a dual, array spectrometer operating in the UV-visible-near-infrared (UV-VIS-NIR) from 285 to 1015 nm.
The satellite bus was built by Bristol Aerospace in Winnipeg. The ACE-FTS was built by ABB-Bomem in Quebec City. MAESTRO was designed and built in a partnership between MSC and the Ottawa based company EMS Technologies with Tom McElroy as the principal investigator.
To fully understand the global ozone budget detailed measurements of species such as \(O_3\), \(H_2 O\), \(CH_4\), \(NO\), \(NO_2\), \(N_2 O_5\), \(N_2 O\), \(HNO_3\), \(HNO_4\), \(HCl\), \(ClNO_3\), \(ClO\), \(CCl_3 F\), \(CCl_2 F_2\), \(HF\), \(CO\) and aerosols, as well as temperature and pressure, are required. Measurements from ACE-FTS are used to retrieve vertical profiles of these, while measurements from MAESTRO are used to retrieve profiles of a subset of these with higher vertical resolution. Furthermore, measurements of aerosol extinction in the VIS, NIR, and mid-IR are required in order to derive the composition, size, and density of aerosols and polar stratospheric clouds. Altogether, these measurements provide valuable insight into ozone chemistry and dynamics, differences between the Arctic and Antarctic ozone distributions, the chlorine budget, and wintertime denitrification.
References
Bernath, P. (2001), The Atmospheric Chemistry Experiment (ACE): An Overview, Spectroscopy from Space, Kluwer Academic Publishers, pp. 147-161.
Bernath, P. F., McElroy, C. T., Abrams, M. C., Boone, C. D., Butler, M., Camy-Peyret, C., Carleer, M., Clerbaux, C., Coheur, P.-F., Colin, R., DeCola, P., DeMazi`ere, M., Drummond, J. R., Dufour, D., Evans, W. F. J., Fast, H., Fussen, D., Gilbert, K., Jennings, D. E., Llewellyn, E. J., Lowe, R. P., Mahieu, E., McConnell, J. C., McHugh, M., McLeod, S. D., Michaud, R., Midwinter, C., Nassar, R., Nichitiu, F., Nowlan, C., Rinsland, C. P., Rochon, Y. J., Rowlands, N., Semeniuk, K., Simon, P., Skelton, R., Sloan, J. J., Soucy, M.-A., Strong, K., Tremblay, P., Turnbull, D., Walker, K. A., Walkty, I., Wardle, D. A., Wehrle, V., Zander, R., and Zou, J.: Atmospheric Chemistry Experiment (ACE): Mission overview, Geophys. Res. Lett., 32, L15S01, https://doi.org/10.1029/2005GL022386, 2005.
McElroy, C. T., Nowlan, C. R., Drummond, J. R., Bernath, P. F., Barton, D. V., Dufour, D. G., Midwinter, C., Hall, R. B., Ogyu, A., Ullberg, A., Wardle, D. I., Kar, J., Zou, J., Nichitiu, F., Boone, C. D., Walker, K. A., and Rowlands, N.: The ACE-MAESTRO instrument on SCISAT: Description, performance, and preliminary results, Appl. Optics., 46, 4341–4356, https://doi.org/10.1364/AO.46.004341, 2007.
Bernath, P. F.: The Atmospheric Chemistry Experiment (ACE), J. Quant. Spectrosc. Ra., 186, 3–16, https://doi.org/10.1016/j.jqsrt.2016.04.006, 2017.