Estudo da razão entre as intensidades das emissões do OI557,7 nm e do OI630,0 nm na região F equatorial.

Abstract

The green line emited by the deexcitation of the oxygen atom from its lS quantum state (01557,7 nm) comes from the two regions of the terrestrial atmosphere, one of them, which is responsible for the greater intensity of emission, is located at the top of mesosphere at an altitude of about 97 km. The other region, called F of the ionosphere and responsible for the less intensity of emission, is situated at an altitude of about 250 km on the average. The optical instruments used for the measurements of the total intensity are unable to sort out the quantity of emission coining from each part of the above cited regions. The most successful experimental technique to this end is the that of photometers installed on the rocket propelled space vehicles which can go up to the hight of 400 km. This technique bears a special advantage to be able to measure the emission profile (intensity versus altitude) in loco of the 01557,7 nm spectral line, however, the cost involved are far higher. It is known that this contribution of about 20% of the emission at 01630,0 nm varies significantly as a function of various atmospheric parameters. Our research work presented here determines the value of the emission of 01557,7 nm, coining from F region. Subtracting the latter contribution from the total intensity of emission we obtain the values corresponding to 01557,7 nm of mesosphere. The total intensity is measured by the photometer installed at Sao Joao do Cariri (7,5 S; 36 W). We have used this technique to obtain the values of the intensities of emission at 01557,7 nm and 01630,0 nm (red line) before and during the passage of the plasma bubbles in the field of view of the photometer referred above. The data presented here were taken from January 1998 to June 2001. We made a judicious selection of 96 events out of this data to determine the ratio of the intensities at the green line (01557,7 nm) to those of the red line (01630,0 nm). The ratio thus obtained is 0,31 ± 0,08 and shows na annual dependence.