Exoplanet atmospheres

Abstract:

A radiometric experiment was conducted to investigate the thermodynamic behaviour of the H2O and CO2 pressure modulated cells of the Pressure Modulator Infrared Radiometer (PMIRR) which flew on "Mars Observer" in 1992. The wave forms and phases of the transmission, emission, pressure and piston position cycles, together with the mean absorption were, for the first time, all measured during the same experiment. The measured transmission and emission cycles were used to calculate the phase and amplitude of the temperature cycles and were found to be super-adiabatic for both cells, in reasonable agreement with a thermal diffusion model. Anomalies were seen in the H2O modulator driving frequency, as has been observed by other authors, but none were evident in the measured cell wave forms suggesting that the water vapour behaves as an ideal gas in the cell. © 1994.