临边探测为中、高层大气探测，主要针对海拔约10—100 km的大气层进行观测，与垂直观测相比，具有更高的垂直分辨率。亚毫米波（0.1—1.0 mm或300 GHz—3 THz）临边探测对臭氧层的大气环保监控具有特殊的意义。本文分析比较了Odin/SMR、EOS AURA/MLS、JEM/SMILES、MASTER与SOPRANO这5个亚毫米波临边探测仪的特性，并介绍了亚毫米波临边探测大气反演系统中的正向模型与反向模型。亚毫米波临边探测器具有较高的光谱分辨率及较宽的波段宽度，其光谱分辨率能达到1 MHz甚至1 MHz以下，波段宽度能达到几个GHz。另外，大气中的许多分子在亚毫米波波段有特征吸收线，可以反演许多痕量气体垂直廓线。在亚毫米波临边探测下，可以获得氯族成分及BrO的廓线数据。HCl、ClO等氯族成分的反演误差可以小于10%，但BrO的反演误差达50%以上。亚毫米波临边探测的正向模型需要考虑云的多次散射；5个亚毫米波临边探测器的反演算法均采用基于高斯-牛顿或Levenberg-Marquardt迭代的最优反演算法。

Limb sounding technique is an important tool for remote observations of Earth's middle atmosphere. It aimed at an altitude of about 10—100 km. Compared with the nadir viewing, limb sounding has a higher vertical resolution. Recently, sub-millimeter (0.1—1.0 mm or 300 GHz—3 THz) limb sounding technique has been developed, which can detect the halogen elements associated with the O₃ processes, a special significance for atmospheric environmental monitoring of the ozone layer. This study overviews five limb sounders (Odin/SMR, EOS AURA/MLS, JEM/SMILES, MASTER and SOPRANO) and their reversion systems. Sub-millimeter limb sounding from space has several advantages. The sounders always have higher spectral resolutions and broader bandwidth. Furthermore, many trace gases have spectral emissions in sub-millimeter ranges. Sub-millimeter limb sounding can provide many species of Cl_y and Br_y with higher precision. The uncertainty of the retrieval profiles of ClO and HCl can be less than 10%. All the reversion systems of the five sub-millimeter limb sounders are based on the OEM (Optimal Estimation Method) with Gauss-Newton or Levenberg-Marquardt iterative. Since the sub-millimeter limb sounding can reach troposphere, the forward model has to consider the multi-scattering by clouds.