Stability of temperatures from TIMED/SABER v1.07 (2002–2009) and Aura/MLS v2.2 (2004–2009) compared with OH(6-2) temperatures observed at Davis Station, Antarctica W. J. R. French1 and F. J. Mulligan2 1Australian Antarctic Division, Kingston, Tasmania, Australia 2National University of Ireland Maynooth, Co. Kildare, Ireland
Abstract. Temperature profiles from two satellite instruments – TIMED/SABER and
Aura/MLS – have been used to calculate hydroxyl-layer equivalent
temperatures for comparison with values measured from OH(6-2) emission lines
observed by a ground-based spectrometer located at Davis Station, Antarctica
(68° S, 78° E). The profile selection criteria – miss-distance
<500 km from the ground station and solar zenith angles >97° –
yielded a total of 2359 SABER profiles over 8 years (2002–2009) and 7407 MLS
profiles over 5.5 years (2004–2009). The availability of simultaneous OH
volume emission rate (VER) profiles from the SABER (OH-B channel) enabled an
assessment of the impact of several different weighting functions in the
calculation of OH-equivalent temperatures. The maximum difference between
all derived hydroxyl layer equivalent temperatures was less than 3 K.
Restricting the miss-distance and miss-time criteria showed little effect on
the bias, suggesting that the OH layer is relatively uniform over the
spatial and temporal scales considered. However, a significant trend was
found in the bias between SABER and Davis OH of ~0.7 K/year over the
8-year period with SABER becoming warmer compared with the Davis OH
temperatures. In contrast, Aura/MLS exhibited a cold bias of 9.9 ± 0.4 K
compared with Davis OH, but importantly, the bias remained constant over the
2004–2009 year period examined. The difference in bias behaviour of the two
satellites has significant implications for multi-annual and long-term
studies using their data.
Citation: French, W. J. R. and Mulligan, F. J.: Stability of temperatures from TIMED/SABER v1.07 (2002–2009) and Aura/MLS v2.2 (2004–2009) compared with OH(6-2) temperatures observed at Davis Station, Antarctica, Atmos. Chem. Phys., 10, 11439-11446, doi:10.5194/acp-10-11439-2010, 2010.