JEM/SMILES limb-sounding of stratospheric trace species I: retrieval algorithm and simulator

In order to estimate measurement capability of the Superconducting Submillimter-Wave Limb-Emission Sounder (SMILES) on the Japanese Experiment Module (JEM) of the International Space Station (ISS) and to clarify the scientific impacts of the JEM/SMILES, we are developing the JEM/SMILES simulator. The simulator consists of the forward model and the inversion model. The forward model calculates a brightness temperature by applying the radiative transfer formula to a limb sounding geometry and simulates the effects of the JEM/SMILES sensor characteristics including optics superconductor-insulator-superconductor (SIS) mixers, Acousto-Optical Spectrometer (AOS), and so on, to it. Because it is important to estimate the effects of the sensor for the retrieval, we develop carefully simulated sensor model. The forward model also calculates weighting functions of molecular, the temperature, the pressure and so on. This paper describes how the brightness temperature and weighting functions are calculated in the forward model and how the effects of the sensor are taken into account in the simulator, and finally shows how the optical estimation method (OEM) is applied to our retrieval model.