Tidal variations of O<sub>2</sub> Atmospheric and OH(6-2) airglow and temperature at mid-latitudes from SATI observations

Abstract

Abstract. Airglow observations with a Spectral AirglowTemperature Imager (SATI), installed at the Sierra Nevada Observatory (37.06 • N, 3.38 • W) at 2900-m height, have been used to investigate the presence of tidal variations at mid-latitudes in the mesosphere/lower thermosphere region. Diurnal variations of the column emission rate and vertically averaged temperature of the O 2 Atmospheric (0-1) band and of the OH Meinel (6-2) band from 5 years (1998)(1999)(2000)(2001)(2002)(2003) of observations have been analysed. From these observations a clear tidal variation of both emission rates and rotational temperatures is inferred. It is found that the amplitude of the daily variation for both emission rates and temperatures is greater from late autumn to spring than during summer. The amplitude decreases by more than a factor of two during summer and early autumn with respect to the amplitude in the winter-spring months. Although the tidal modulations are preferentially semidiurnal in both rotational temperatures and emission rates during the whole year, during early spring the tidal modulations seem to be more consistent with a diurnal modulation in both rotational temperatures and emission rates. Moreover, the OH emission rate from late autumn to early winter has a pattern suggesting both diurnal and semidiurnal tidal modulations.

Summer-time nocturnal wave characteristics in mesospheric OH and O2 airglow emissions

“…The deduced values with our OH and O 2 data compares well with those of Reisin and Scheer (1996), however, with the OH values being in approximate agreement. In another study, Lopez-Gonzalez et al (2005), based on long-term observations with a spectral airglow temperature imager (SATI) from a mid-latitude station, reported a mean |η| of approximately 5.89 for semi-diurnal tides during April to September for the O 2 data and an |η| of approximately 18.1 for the OH data, with extreme variability (range shown in Fig. 3); these results do not agree with our results.…”

“…Noteworthy, the values reported by Reisin and Scheer (1996), who found a mean VW for OH of approximately −30 km and one for O 2 of approximately −40 km, with ∼40 km variability, are somewhat in agreement with our values. However, Lopez-Gonzalez et al (2005) observed approximately the same values-around approximately −10 km for OH and approximately −40 km for molecular oxygen.…”

“…The best-fit result shows that 8.6±0.1-h and 8.8±0.3-h waves with amplitude 10.5±0.4 K and 10.9±0.7 K are present in the OH and O 2 temperature data, respectively (small differences in values with earlier reported periodicities and amplitudes by Taori et al (2005) are the result of different methods adopted for As mentioned above, the deduced Krassovsky parameters, show large differences from one night to other, indicating a high degree of dynamical variability at mesospheric altitudes during July 2002 over Hawaii. Figure 3 shows a comparison of our results for η and with those of earlier reports, taking the average arithmetic value with respect to periodicity, which ranges from 6-to 12-h waves (Viereck and Deehr, 1989;Takahashi et al, 1992;Oznovich et al, 1995Oznovich et al, , 1997Drob, 1996;Reisin and Scheer, 1996;Taylor et al, 2001;Lopez-Gonzalez et al, 2005), and model estimates of Schubert et al (1991), Tarasick and Shepherd (1992a, b), Walterscheid and Schubert (1995), and Hickey et al (1993). It is evident that the observed η and ϕ values in our study show a large spread in their distribution as compared to the model values.…”

Climatology of planetary wave type oscillations with periods of 2–20 days derived from O<sub>2</sub> atmospheric and OH(6-2) airglow observations at mid-latitude with SATI

“…Other modulations of short periods (about hours) that could be present during individual nights cannot be identified in the periodograms above a solid level of significance. The diurnal and semidiurnal tides have been studied in SATI data by López-González et al (2005). A distinct seasonal behaviour in the tidal variations was found in SATI data: a mainly semidiurnal tidal variations in both rotational temperatures and emission rates throughout the entire year except during early spring when the tidal variations seem to be consistent with a diurnal modulation.…”

Development of airglow temperature photometers with cooled-CCD detectors

“…The Spectral Airglow Temperature Imager (SATI) was subsequently developed as a revision of MORTI, measuring rotational temperatures of both the OH and O 2 bands (Wiens et al, 1997;Sargoytchev et al, 2004). SATI has been widely introduced in Spain, Japan, and Canada (e.g., Won et al, 2003;López-González et al, 2004;Shiokawa et al, 2004;Cho and Shepherd, 2006).…”