Development of very sensitive heterodyne spectrometer at millimeter and infrared wavelength for strato-mesospheric atomospheric minor components

地面微波传感器通常用于通过被动探测平流层关键分子（如臭氧）的旋转跃迁来遥感痕量成分。这种方法在测量日变化和短期变化方面比其他技术有明显的优势。微波观测测量分子的热发射，然后测量不需要像吸收测量那样的背景辐射源。观测也不需要晴朗的天空，可以在白天和晚上进行测量。然而，常规的臭氧监测方法不能对臭氧浓度和高度分布进行满意的实时监测，为此，我们研制了一种利用超导体-绝缘体超导体（SIS）混频器的系统，该系统具有迄今为止报道的最好的噪声特性.在36 - 75 km不同高度上混合比的日变化与许多作者的理论计算和观测结果一致，但在中间层顶部附近的夜间变化除外. 70 km附近的臭氧混合比夜间变化幅度约为午夜值的20%，用积分时间为3 min的观测资料得到了日出前和日落后的混合比的时间变化

Ground-based microwave sensor are commonly used in remote sensing of trace constituents by passive sounding of rotational transition of key stratospheric molecules, such as ozone. This method has a distinctive advantage for measurements of diurnal and short term variations over other techniques.The microwave observations measure thermal emission of molecules and then measurement dose not require a background radiation source like the sun as is the case in absorption measurement.The observations does not also require a clear sky and measurements can be made throughout the day and the night.However, conventional ozone monitoring method do not enceble satisfactory realtime monitoring of concentration and altitude distribution.Accordingly we have developed a system using superconductor-insulator superconductor (SIS) mixer having the best noise characteristics reported to date.Summarizing observations obtained by our instrument, we may conclude as follows.1. Diurnal variations of the mixing ratio at various altitudes from 36 through 75 km appear in agreement with theoretical calculations and observations by many authors except night-time variations near the top of the mesosphere.2. The ozone mixing ratio about 70 km shows night-time variation variable from day to day with an amplitude of about 20% of the midnight value.Time variations of the mixing ratio just before the sunrise and after the sunset are obtained from observations with an integration time of 3 minutes