Atmospheric Density, Pressure and Temperature Profile Reconstruction from Refractive Angle Measurements in Stellar Occultation

Abstract

Stellar occultation instruments have high pointing accuracy and they follow point-like sources. These two features allow accurate measurements of the refractive angle in the limb viewing geometry. The determination of the stratospheric density and temperature profiles from the refractive-angle measurements by stellar occultation instruments is considered. The temperature reconstruction consists of the following steps. First, refractivity is reconstructed from the refractive angle measurements using inversion of the Abel-type integral. Refractivity is connected with air density via the Edlen formula. Then the pressure profile is calculated using the hydrostatic equation. Finally, the temperature profile is determined from the density and pressure data using the equation of state of a perfect gas. The error analysis was performed by the Monte-Carlo simulations with additive Gaussian noise. Main error sources are identified and sensitivity of the inverse procedure to them is studied. The accuracy attainable in the temperature profiling with the present design of the stellar occultation instruments is analyzed.