A study group consisting of the University of Electro-Communications (UEC), National Institute of Information and Communications Technology (NICT), Meiji University, National Institute of Polar Research (NIPR), and Kyushu University has devised a method to observe noctilucent clouds (NLCs) appearing at 80-85 km altitude by focusing on the rim of the Earth captured in the disk images from the geostationary meteorological satellite Himawari 8. The group has established a real-time NLCs monitoring system using the satellite data. With the new monitoring method of NLCs or “Climate Canary”, contributions to studies related to climate changes including global warming are expected.


Noctilucent clouds or NLCs consist of water-ice particles and appear at an altitude of 80-85 km. It is considered that cooling of the upper atmosphere accompanying global warming promotes the generation of these clouds. Since NLCs, or “Climate Canary” are visual signifiers of upper atmospheric cooling and global warming, having a system to monitor NLCs with high sensitivity is considered important for the tracking of climate change.


The study group has provided a method to detect NLCs appearing at 80–85 km altitude by focusing on the rim of the Earth in the disk images obtained from Himawari 8. The group has then established a system to monitor the NLCs activity with real-time satellite data using the newly developed detection algorithm. The new observation method verified sufficient sensitivity to capture NLCs variation.
In this achievement, NICT made contributions from two aspects of atmospheric science and data science:
- It contributed to the development of a detecting method of NLCs, and
- provided (and continuously providing) the satellite data for the real-time monitoring system.
Figure 1: Outline of Observation of NLCs Using Himawari 8
Figure 1: Outline of Observation of NLCs Using Himawari 8

Future Prospects

The real-time monitoring system of NLCs using Himawari-8 data is available on UEC’s website (http://ttt01.cei.uec.ac.jp/himawari/). The website is open to the public and provides the current status of NLCs' global activity. The NLCs status on the website will assist you in distinguishing the NLCs from the ordinary clouds in the twilight. The details of the research results were reported in the 150th General Assembly of the society of Geomagnetism and Earth, Planetary and Space Sciences, held online on November 2nd, 2021.

Contact information

MURATA Takeshi
ICT Testbed Research and Development Promotion Center, Social Innovation Unit, Open Innovation Promotion Headquarters

Tel: +81-42-327-7931

E-mail: ken.murata_attmark_nict.go.jp

Space Environment Laboratory, Radio Propagation Research Center, Radio Research Institute

Tel: +81-42-327-7179

E-mail: hozumi_attmark_nict.go.jp

TSUDA Takuo, Associate professor
Department of Computer and Network Engineering, Graduate School of Informatics and Engineering, the University of Electro-Communications (UEC)

Tel: +08-42-443-5214

E-mail: takuo.tsuda_attmark_uec.ac.jp