Abstract: Long-term observations and data analysis of the Earth’s middle and upper atmosphere, an
important region for the study of atmospheric processes and even climate change for the study of human activities
and climate change, are still sorely lacking. Terahertz limb-sounding technology can obtain atmospheric profiles
all day and near all-weather with high vertical resolution (about 1~5 km), and is particularly sensitive to some of
the halogen gases associated with ozone depletion which is an important method to measure the Earth's middle
and upper atmosphere parameters. The Earth’s middle and upper atmosphere constitutes a crucial region for
studying atmospheric processes and even climate change. However, there remains a significant lack of long-term
observational data and comprehensive analysis for this atmospheric layer. Terahertz limb sounding technology
has emerged as a vital tool for measuring atmospheric parameters in these regions, capable of obtaining
atmospheric profiles with relatively high vertical resolution (1~5 km) under near-all-weather conditions with
diurnal availability. Particularly sensitive to halogen gases associated with ozone depletion, this technology offers
unique advantages. Focusing on terahertz limb sounding technology, this study systematically reviews the
technological evolution and current status of terahertz payloads: While existing systems have successfully
achieved high vertical resolution measurements of multiple trace gases in the middle and upper atmosphere,
current payloads still face challenges such as bulky system configurations and inadequate noise suppression
capabilities. Based on newly developed prototype payloads, next-generation terahertz detection systems primarily
emphasize advancements in low-noise and miniaturization technologies. Regarding data processing, conventional
physical retrieval algorithms suffer from low computational efficiency. The introduction of artificial intelligence
technology demonstrates potential to significantly enhance retrieval efficiency while maintaining accuracy. Future
development urgently requires breakthroughs in core technologies including terahertz low-noise receivers and
high-resolution digital spectrometers, which will further propel the advancement of terahertz limb sounding
technology in China.