Simulation of the Middle and Upper Atmospheric Wind Measurement of THz Atmospheric Limb Sounder

Middle and upper atmospheric wind is a key parameter in atmospheric science. Ground-based radar, lidar, and interferometer are usually used to measure the atmospheric wind. Up to now, the payload which can measure the atmospheric wind from space is quite scarce. Microwave limb sounding can also measure wind in the middle and upper atmosphere. THz Atmospheric Limb Sounder (TALIS) is the first Chinese microwave limb sounder being developed for atmospheric vertical profile observation. The main targets of TALIS are atmospheric vertical profiles of temperature, pressure and chemical species such as H₂O, O₃, HCl, ClO, N₂O, HNO₃. Since TALIS covers many strong lines, the observation data will contain doppler information of atmospheric wind, so it can be used to retrieve the atmospheric wind. In this paper, a simulation is performed to evaluate the precision of wind retrieval by using the Atmospheric Radiative Transfer Simulator (ARTS). The results suggest that 118GHz retrieval has a better precision of 12m·s^-1 at 70km. The precision of 183GHz, 633GHz and 658GHz are 19m·s^-1 (60km), 19m·s^-1 (50km), 16m·s^-1 (50km), respectively. 655GHz is a candidate band that has a large potential for wind measurement in the stratosphere and its precision is 11m·s^-1 at 55km. The simulation also shows that reducing the spectral resolution to improve the NEDT has almost no contribution to a better retrieval precision. Reducing the system noise temperature is the only way to improve the precision.