Non-LTE diagnostics of the infrared observations of the planetary atmosphere

The analysis of the infrared measurements of a number of sophisticated space experiments requires modeling of molecular infrared radiation with accounting for the nonlocal thermodynamic equilibrium (non--LTE). In this dissertation a general formulation is given of the multilevel vibrational-rotational non-LTE problem for a mixture of radiating molecular gases in a planetary atmosphere. The approach for the solution of this problem suggested here utilizes the Accelerated Lambda Iteration (ALI) technique developed in stellar astrophysics for spectrum formation calculations and for the computation of non-LTE model stellar atmospheres. This new for atmospheric science technique is not subject to the limitations of the traditional matrix and conventional lambda iteration methods which dominate the studies dealing with non-LTE in planetary atmospheres. In the case of the CO2 non-LTE problems in the atmospheres of Earth and Mars it is demonstrated that ALI approach is far superior to the other algorithms in minimizing computer time and storage and in converging much more rapidly. While ``atmospheric'' groups concentrated on the development of codes suitable for treatment of limited number of selected non-LTE problems the computer code package ALI-ARMS (for ``Accelerated Lambda Iteration for Atmospheric Radiation and Molecular Spectra'') compiled in framework of this study allows non-LTE treatment of arbitrary number of molecules interacting by collisionally induced exchange of energy and by the band overlaps. It was applied to the analysis of large amount of the infrared limb radiance data obtained both in the CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiments on board of the german ASTRO-SPAS satellite and by the Thermal Emission Spectrometer (TES) instrument orbiting Mars on board of the NASA Mars Global Surveyor (MGS) satellite. In case of the Earth's atmosphere first detailed distributions of temperature and trace gas concentrations in the upper mesosphere and lower thermosphere were obtained. The retrieved temperature data confirmed the ``two-level'' structure of the Earth's mesopause which was recently discovered in the lidar and rocket experiments. These results contribute to the studies of the mesosphere, which is considered today to be the tracer of the global climate changes.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Ludwig-Maximilians-Universität

Year

2003

Author dc:creator

• Goussev, Oleg

Repository record source_url

https://edoc.ub.uni-muenchen.de/1056/

OAI identifier oai:identifier

oai:edoc.ub.uni-muenchen.de:1056