A global climatology of the mesospheric sodium layer from GOMOS data during the 2002–2008 period 1Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Brussels, Belgium
2Earth observation, Finnish Meteorological Institute, Helsinki, Finland
3LATMOS, Université Versailles Saint-Quentin, CNRS/INSU, Verrières-le-Buisson, France
4ACRI-ST, Sophia-Antipolis, France
5European Space Research Institute, European Space Agency, Frascati, Italy
6Department of Physics, Colorado State University, Fort Collins, USA
Received: 13 December 2009 – Published in Atmos. Chem. Phys. Discuss.: 03 March 2010 Abstract. This paper presents a climatology of the mesospheric sodium layer built from the processing of 7 years
of GOMOS data. With respect to preliminary results already published for the year 2003, a more careful
analysis was applied to the averaging of occultations inside the climatological bins
(10° in latitude-1 month). Also, the slant path absorption lines of the Na doublet around 589 nm shows
evidence of partial saturation that was responsible for an underestimation of the Na concentration in our previous results.
The sodium climatology has been validated with respect to the Fort Collins lidar measurements and,
to a lesser extent, to the OSIRIS 2003–2004 data. Despite the important natural sodium variability, we
have shown that the Na vertical column has a marked semi-annual oscillation at low latitudes that
merges into an annual oscillation in the polar regions,a spatial distribution pattern that was unreported so far.
The sodium layer seems to be clearly influenced by the mesospheric global circulation and the altitude
of the layer shows clear signs of subsidence during polar winter.
The climatology has been parameterized by time-latitude robust fits to allow for easy use. Taking into
account the non-linearity of the transmittance due to partial saturation, an experimental approach is
proposed to derive mesospheric temperatures from limb remote sounding measurements.
Revised: 08 July 2010 – Accepted: 09 September 2010 – Published: 01 October 2010
Citation: Fussen, D., Vanhellemont, F., Tétard, C., Mateshvili, N., Dekemper, E., Loodts, N., Bingen, C., Kyrölä, E., Tamminen, J., Sofieva, V., Hauchecorne, A., Dalaudier, F., Bertaux, J.-L., Barrot, G., Blanot, L., Fanton d'Andon, O., Fehr, T., Saavedra, L., Yuan, T., and She, C.-Y.: A global climatology of the mesospheric sodium layer from GOMOS data during the 2002–2008 period, Atmos. Chem. Phys., 10, 9225-9236, doi:10.5194/acp-10-9225-2010, 2010.