We present a method to mitigate the atmospheric effects (residual atmospheric lines) in single-dish radio spectroscopy caused by the elevation difference between the target and reference positions. The method is developed as a script using the Atmospheric Transmission at Microwaves (ATM) library built into the Common Astronomy Software Applications (CASA) package. We apply the method to the data taken with the Total Power Array of the Atacama Large Millimeter/submillimeter Array. The intensities of the residual atmospheric (mostly O₃) lines are suppressed by, typically, an order of magnitude for the tested cases. The parameters for the ATM model can be optimized to minimize the residual line and, for a specific O₃ line at 231.28 GHz, a seasonal dependence of a best-fitting model parameter is demonstrated. The method will be provided as a task within the CASA package in the near future. The atmospheric removal method we developed can be used by any radio/millimeter/submillimeter observatory to improve the quality of its spectroscopic measurements.

我们提出一种方法来减轻目标位置和参考位置之间的高程差引起的单皿无线电光谱中的大气影响（残留大气线）。使用内置在通用天文软件应用程序（CASA）程序包中的“微波大气传输（ATM）”库，将该方法开发为脚本。我们将该方法应用于使用Atacama大毫米波/亚毫米波阵列的总功率阵列获取的数据。对于测试情况，通常通过一个数量级抑制残余大气（主要是O ₃）线的强度。可以对ATM模型的参数进行优化，以最大程度地减少残差线，并针对特定的O ₃线在231.28 GHz时，证明了最佳拟合模型参数的季节依赖性。该方法将在不久的将来作为CASA软件包中的一项任务提供。我们开发的大气去除方法可用于任何无线电/毫米波/亚毫米波天文台，以提高其光谱测量的质量。