This webinar will cover several topics related to Global Navigation Satellite System (GNSS) radio occultation. We will begin with a background on the computation of bending angle and refractivity profiles from GNSS measurements taken in low-Earth orbit, as well as derived atmospheric products (e.g. temperature, pressure, humidity) used by global weather centers. Current status of existing low-Earth orbit radio occultation satellites, including COSMIC-1, KOMPSAT-5 , MetOp, and other missions of opportunity will be discussed. We will highlight science impacts in the areas of numerical weather prediction, forecasting cyclone genesis, and space weather. Finally, we'll provide a look at the upcoming six satellite COSMIC-2 constellation.