Observations of atomic deuterium in the mesosphere from ATLAS 1 with ALAE Instrument

Jean-Loup Bertaux (1) , Eric Quémerais (1) , Florence Goutail (1) , Gaston Kockarts (2) , Bill R. Sandel (3)

1 SA - Service d'aéronomie
2 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
3 LPL - Lunar and Planetary Laboratory [Tucson]

During the first ATLAS mission, the ALAE Lyman α spectrophotometer collected various measurements of hydrogen and deuterium atoms, from the mesosphere, the thermosphere, the exosphere and the interplanetary medium. In this paper is presented a preliminary analysis of some observations of atomic deuterium, which Lyman α emission is excited by resonance scattering of solar photons. Nadir measurements along the sunlit Earth part of the orbit show that the emission changes as a function of solar zenith angle. Comparison with a simple model shows that, from the shuttle altitude of 300 km and at low solar zenith angles, the line‐of‐sight probes atomic deuterium down to 80 km of altitude (where O 2 absorption is complete), whereas at angles from 60° to 90°, the mesospheric part of the emission progressively vanishes. Then, the remaining emission mainly consist of the thermospheric part (z ≥ 100 km). This type of observations provides a sounding of atomic deuterium at its peak production and concentration, and D atoms can be used as a proxy to H atoms (which cannot be observed from a satellite) in this particularly active region of the mesosphere.

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]

Jean-Loup Bertaux, Eric Quémerais, Florence Goutail, Gaston Kockarts, Bill R. Sandel. Observations of atomic deuterium in the mesosphere from ATLAS 1 with ALAE Instrument. Geophysical Research Letters, 1993, 20 (6), pp.507-510. ⟨10.1029/93GL00077⟩. ⟨insu-02889811⟩