| Planets including atmosphere in solar system have Earth, Mars, Jupiter, Venus, and so on. The atmospheric composition and structure of every planet is different. It is of great significance to detect of the planetary atmospheric composition and monitor environmental changes to study and simulate the process of the planetary atmospheric radiation transmission. Microwave and sub-millimeter wave is one of the important means for remote sensing of atmosphere and surface of planet. Microwave wave and sub-millimeter wave atmospheric absorption mode MPM and PWR which are commonly used can only get the absorption coefficient of water vapor, oxygen and nitrogen in the 1-1000 GHz, and can’t simulate absorption characteristics of other gases or at higher frequencies.Focusing on the demand of detection of the earth’s upper atmospheric composition or atmosphere of other planets, line-by-line integration method is used in this thesis. Based on the parameters of gas molecules in HITRAN database, the absorption feature of every gas molecule is simulated in microwave and sub millimeter wave range. The planetary atmospheric radiation brightness temperature using different sounding methods is simulated by using radiative transfer equation. The work provides model and theoretical basis for atmospheric composition detection simulation, selection of detection frequency band and retrieval of atmosphere profiles of Earth and other planets.Atmospheric composition and structure of the earth and Mars are first described in detail. The detection mechanism of three kinds of observation modes are described, which are upward-looking, nadir observation and limb sounding. The microwave wave and sub-millimeter wave atmospheric absorption mode MPM and PWR which are commonly used are analyzed. In addition, the characteristics of microwave and sub millimeter wave atmospheric radiation transmission model in foreign countries are introduced.Absorption coefficient of gases is calculated by using line-by-line integration method. In the process of line by line integration, how to choose line shape in different pressure and temperature is analyzed. In order to improve calculation speed without affecting accuracy, truncation method is adopted and line by line integration method and MPM/PWRM model are compared. Absorption coefficient from 1 to 3000 GHz of the gases included in planetary atmosphere at a given temperature, pressure, and density are calculated, analyzing absorption characteristics of each gas. System error caused by intensity and air-broadened half-width from HITRNA2012 is quantitatively analyzed.Process of planetary atmospheric radiation transmission is simulated by using radiative transfer equation. Atmospheric radiation brightness temperature of earth using upward-looking, nadir observation and limb sounding mode is simulated. The feasibility of detecting atmospheric pollutants by microwave and sub millimeter radiometer and the sensitivity of atmospheric composition change using limb viewing mode are analyzed. According to the results of Mars atmospheric exploration, the atmospheric profile information of Mars is assumed, and atmospheric radiation brightness temperature of Mars using limb sounding mode is simulated. The work provides a theoretical basis for the channel design of planetary atmosphere sounding system and the acquisition of scientific goal. |
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