Astroclimate measurements on several points over Eastern hemisphere in 2-mm and 3-millimeter atmospheric transparency windows using tipping radiometer

We are presenting results of the atmospheric propagation observations which our research group has been conducting since 2012. Over this time, we have gathered statistical data of atmospheric propagation over a number of sites which possibly can be used for radio astronomical observations in the millimetre and sub-millimetre bandwidths. The Zenith opacity was studied by the atmospheric dip method in the 3 mm and 2 mm atmospheric windows. The dataset is recommended to use for estimation of atmospheric propagation for the purpose of radio astronomy and telecommunications. The “tau-meter” (named MIAP-2) allows us to estimate an integral absorption by using the atmospheric dip method. The hardware includes a radiometric system comprising two self-contained radiometers operating in two different bands of 84-99 GHz (λ ~ 3 mm) and 132-148 GHz (λ ~ 2 mm), a rotary support, a control, and a firmware system. The radiometers work in modulation mode within 36 Hz modulation frequency. Floating mirror allows radiometer to scan the sky in the interval of 0 – 88.5 elevation angles (6 total). The output record contains the voltages of synchronous detector for each angle in 2 wavebands. The voltage is proportional to brightness temperature of the sky in corresponding waveband. (It has negative value for technical reasons.) The dataset contains raw data observed by radiometer: Local date and time, a several detector voltages on different elevation angles for 2 wavebands, as well as service information header. The first 6 columns contain optical depth calculated by old method and it’s no more used in data processing since the new algorithm has been invented in 2018.本研究团队自2012年起开展大气传播观测研究，现将相关观测结果予以公布。在此期间，我们已在多个适用于毫米波与亚毫米波频段射电天文观测的观测站点采集了大气传播统计数据。本研究采用大气凹陷法，针对3mm与2mm大气窗口开展了天顶不透明度相关研究。本数据集可用于射电天文与通信领域的大气传播特性评估，特此推荐。这款名为MIAP-2的“光深计（tau-meter）”可通过大气凹陷法估算大气积分吸收量。该观测硬件系统包含一套辐射测量装置：两台分别工作于84~99 GHz（波长λ≈3mm）与132~148 GHz（波长λ≈2mm）频段的独立辐射计、旋转支架、控制系统与固件系统。辐射计工作于36Hz调制频率的调制模式下。浮动反射镜可使辐射计在0°至88.5°的仰角区间内进行天空扫描，共计6个扫描位置。输出记录包含两个频段下各观测仰角对应的同步探测器电压信号。该电压与对应频段的天空亮温呈正比关系（因技术原因，电压值为负值）。本数据集包含辐射计采集的原始观测数据：本地日期与时间、两个频段下不同仰角对应的多组探测器电压，以及服务信息头文件。数据前6列为采用旧方法计算得到的光学厚度，自2018年新算法研发成功后，该旧方法已不再用于数据处理流程。