Upper atmosphere research at the Instituto Nacional de Pesquisas Espaciais of Brazil

Abstract

Upper atmosphere research at the Instituto Nacional de Pesquisas Espaciais of Brazil is concentrated in the areas of photochemistry and dynamics of the mesopause and lower thermosphere, middle atmosphere climatology, and stratospheric aerosols. The main emphasis is on mesopause region dynamics. Experimental studies are carried out by lidar, airglow, meteor radar and rocket-borne techniques. A lidar at São José dos Campos (23° S, 46° W) measures the vertical distribution of atmospheric sodium between 80 and 110 km, the atmospheric density profile, from 35 to 70 km, and stratospheric aerosols around 20 km. Airglow photometers at Cachoeira Paulista (23° S, 45°W) and São João do Cariri (7° S, 37° W) measure emissions from atomic and molecular oxygen, hydroxyl and sodium. Temperature in the 75-95 km region is determined from the rotational spectrum of OH and O₂. An imaging system measures the horizontal structure of the same emissions in São João do Cariri. These observations are aimed mainly at studying the propagation of internal gravity waves and their effects on the atmosphere in the mesopause region. A meteor radar at Cachoeira Paulista is used to determine wind structure between 80 and 110 km on a 24-hour basis, with the main purpose of studying atmospheric tides and planetary waves. Occasional rocket experiments launched from Natal (6° S, 35° W) or Alcântara (2° S, 44.5° W) are used to study the vertical distribution of airglow emissions and their relationship with other atmospheric parameters.