Solar cycle signature and secular long-term trend in OH airglow temperature observations at South Pole, Antarctica

[1] We have examined Michelson Interferometer OH airglow temperature data to investigate solar cycle and long-term variations of mesospheric temperatures at South Pole Station (SPS), Antarctica (90 degrees S). The data set used here is continuous (24 hours a day) and taken during 1994-2004 austral winters. We have used a Multiple Linear Regression (MLR) technique to elucidate solar cycle and the trend term in the MI temperature time series data. The 11-year time series of OH rotational temperature shows a strong correlation with F10.7 radio flux (R = 0.60). The amplitude of solar cycle response seen in the mesopause temperature records at South Pole is about 0.04 +/- 0.01 K/sfu (Solar Flux Units), however, the trend term is statistically insignificant and is about 0.1 +/- 0.2 K/year. Superposed epoch studies have been carried out in order to determine climatological variations in OH temperatures above South Pole derived from 11 years of austral winter observations. The mean amplitude of this variation is about 12.6 K and its maximum occurs near 30 May which is in agreement with the Fabry-Perot Spectrometer (FPS) observations of OH temperatures at SPS (Hernandez, 2003). However, whereas Hernandez (2003) reported 35 K cooling in 2002, MI OH temperatures at SPS do not show any significant deviation from previous years.