Portal de Periódicos da CAPES

Artigo Produção Nacional

BIBTEX RIS

Predominant semi-annual oscillation of the upper mesospheric airglow intensities and temperatures in the equatorial region

1995; Elsevier BV; Volume: 57; Issue: 4 Linguagem: Inglês

10.1016/0021-9169(94)e0006-9

1878-593X

H. Takahashi, B. R. Clemesha, P. P. Batista,

Solar and Space Plasma Dynamics

The upper mesospheric and lower thermospheric airglow emissions, OI 557.7 nm, NaD 589.3 mn and the OH (9,4) band and its rotational temperature have been measured using a ground-based multichannel airglow photometer located at Fortaleza (3.9°S, 38.4°W) since 1986. The observed emission intensities show predominantly semi-annual oscillations with maxima at the equinoxes and minima during the solstices. The amplitudes of the oscillations are larger than those observed from the low latitude station, Cachoeira Paulista (22.7°S, 45.0°W). The OH rotational temperature, which represents a gas kinetic atmospheric temperature at around 85–95 km, also shows a strong semi-annual oscillation, 18 K peak to peak, with an. average value around 10 K higher than that observed from Cachoeira Paulista. These results do not agree with model atmospheres presently available. It is suggested that the differences result from the effects of seasonal variations in vertical eddy transport and/or meridional circulation.