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

摘要

The middle- and upper-atmospheric energy budget is largely dominated byreactions involving atomic oxygen (O). Modeling of these processesrequires detailed knowledge about the distribution of this oxygen species.Understanding the mutual contributions of atomic oxygen and wave motions tothe atmospheric heating is the main goal of the rocket project WADIS (WAvepropagation and DISsipation in the middle atmosphere). It includes, amongstothers, our instruments for the measurement of atomic oxygen that have bothbeen developed with the aim of resolving density variations on small verticalscales along the trajectory. In this paper the instrument based on catalyticeffects (PHLUX: Pyrometric Heat FluxExperiment) is introduced briefly. The experiment employing solidelectrolyte sensors (FIPEX: Flux φ(Phi) Probe Experiment) is presented in detail. These sensors werelaboratory calibrated using a microwave plasma as a source of atomic oxygenin combination with mass spectrometer reference measurements. Thespectrometer was in turn calibrated for O with a method based onmethane. In order to get insight into the horizontal variability, the rocketpayload had instrument decks at both ends. Each housed several sensor headsmeasuring during both the up- and downleg of the trajectory. The WADISproject comprises two rocket flights during different geophysical conditions.Results from WADIS-1 are presented, which was successfully launched in June2013 from the And?ya Space Center, Norway. FIPEX data were sampled at100 Hz and yield atomic oxygen density profiles with a verticalresolution better than 9 m. This allows density variations to bestudied on very small spatial scales. Numerical simulations of the flow field aroundthe rocket were done at several points of the trajectory to assess theinfluence of aerodynamic effects on the measurement results. Density profilespeak at 3 × 1010 cm?3 ataltitudes of 93.6 and 96 km for the up- and downleg,respectively.