Measurement of atomic oxygen in the middle atmosphere using solid electrolyte sensors and catalytic probes

Abstract

Abstract. The atmospheric energy budget is largely dominated by reactions involving atomic oxygen (O). Modeling of these processes requires detailed knowledge about the distribution of this oxygen species. Understanding the mutual contributions of atomic oxygen and wave motions to the atmospheric heating is the main goal of the rocket campaign WADIS. It includes, amongst others, two of our instruments for the measurement of atomic oxygen that have both been developed with the aim of resolving density variations on small vertical scales along the trajectory. In this paper the instrument based on catalytic effects (PHLUX) is introduced briefly. The experiment employing solid electrolyte sensors (FIPEX) is presented in detail. These sensors were laboratory calibrated using a microwave plasma as a source for atomic oxygen in combination with mass spectrometer reference measurements. The spectrometer was in turn calibrated for O with a method based on methane. In order to get insight into the horizontal variability the rocket payload had instrument decks at both ends. Each housed several sensor heads measuring during both the up- and downleg of the trajectory. The WADIS campaign comprises two rocket flights during different geophysical conditions. Results from WADIS-1 are presented which was successfully launched in June 2013 from Andøya Rocket Range, Norway. FIPEX data was sampled with 100 Hz and yield atomic oxygen density profiles with a vertical resolution better than 10 m. Numerical simulations of the flow field around the rocket were done at several points of the trajectory to assess the influence of aerodynamic effects on the measurement results. Density profiles peak at 3 × 1010 cm−3 at altitudes of 93.6 and 96 km for up- and downleg respectively.