Daytime lidar measurements of the mesospheric ozone layer
Résumé
Daytime lidar measurements of the mesospheric sodium layer have been performed at the Haute Provence Observatory from 1979 to 1981. High values of the signal to noise ratio (> 50) are obtained by simultaneously reducing the receiver bandwidth down to 20 pm and its field of view to 3.10 -4 radian. The long term behaviour of the sodium layer during daytime is similar to the one already observed for nighttime by previous lidar soundings. No regular variation of the characteristics parameters of the sodium layer-total content, altitude of the concentration maximum, topside and bottom side scale heights-during the diurnal cycle or during day-night transitions have been observed, suggesting that the photochemical processes are not dominant in governing the behaviour of the upper atmospheric sodium atoms.