Contributions of Radio Occultation to Weather and Climate
Using the world’s most accurate and precise thermometer from space
The launch of the proof-of-concept mission GPS/MET (Global Positioning System/Meteorology) in 1995 began a revolution in profiling Earth’s atmosphere through radio occultation (RO). The six-satellite constellation, FORMOSAT-3/COSMIC (Formosa Satellite mission #3)/Constellation Observing System for Meteorology, Ionosphere, and Climate), launched in 2006, has proven the theoretical capabilities of RO to provide accurate and precise profiles of electron density in the ionosphere and refractivity, containing information on temperature and water vapor, in the stratosphere and troposphere.
Radio occultation has been dubbed “the most accurate and precise thermometer from space.” No other observing system provides such high-quality, global observations of the ionosphere, stratosphere and troposphere. These are having a high impact in operational weather forecasting, climate monitoring and research, as well as ionospheric research and space weather. Radio occultation typically ranks in the top five of all observing systems in contributing to the accuracy of operational global numerical weather prediction models. The relatively low cost of RO compared to other space-based systems make them highly cost-effective for research and applications.
A follow-on mission, COSMIC-2, will consist of a 6-satellite constellation in Equatorial orbit and producing 5,000 soundings per day between 30°N and 30°S. The Equatorial constellation will be launched in late 2018 or early 2019. COSMIC-2 will have more advanced RO receivers and higher-gain antennas, and should produce even higher quality soundings than COSMIC. Because the constellation is in an Equatorial orbit, it will be particularly valuable for studying tropical cyclones.
My talk highlights recent scientific results using RO observations, with an emphasis on climate, and introduces COSMIC-2.