AMATERASU: Model for atmospheric TeraHertz Radiation analysis and simulation

Journal article, 2008

We describe the current status of the Advanced Model for Atmospheric TeraHertz Radiation Analysis and Simulation (AMATERASU) that is being developed in the framework of the NICT THz project. This code aims to be used for studying the insterest of the THz frequency region for atmospheric remote sensing, communication systems and estimate the impact of the THz thermal atmospheric emission in the Earth energy budget. This paper presents the first stage of the model development that concerns a non scattering and a horizontal homogeneous atmosphere, e.g., the geophysical parameters are only altitude dependent. A scattering module is being developed but it is presented in an other paper in this issue. The model is based on the Microwave Observation and Lines Estimation and REtrieval code (MOLIERE). The absorption coefficient module has been modified in order to extend the frequency coverage from the submillimeter wavelength to the near InfraRed region. A new radiative transfer module has been implemented that can handle the different types of optical paths and any location for the receiver. AMATERASU includes the original MOLIERE instrument simulator and retrieval codes. The validation methodology is discussed and some examples of the current applications are given. The next steps of the development are presented in the conclusion including the modeling of the horizontal inhomogeneties in the atmopshere.