GNSS-RO & GPS-RO
Global Positioning System Radio Occultation (GPS-RO) and Global Navigation Satellite System Radio Occultation (GNSS-RO) refer to radio occultation that involves a signal from a geospatial satellite to a satellite in low Earth orbit (LEO).
As the signal between the satellites travels through the atmosphere, it is refracted; the magnitude of this refraction is dependent upon temperature and water vapor content, allowing for relevant weather data to be derived as the GPS satellite passes through different levels of the atmosphere. The combination of high precision, high vertical resolution, and global coverage enables accurate weather-related data collection.
Kleiner K. GPS “thermometer” could flag up climate change. New Scientist. Accessed 3 Oct 2016.