 Good afternoon. I'm Bill Schreiner. I'm from the UCAR Cosmic Program, and I'm going to talk about the Consolation Observing System for meteorology, ionosphere, and climate, atmospheric sounding from space with GPS radio occultation. Here's the outline of my talk. I'm going to give an overview of radio occultation, then give a cosmic mission overview, then talk to some science applications of RO, cosmic two mission status, and then a summary. Radio occultation was first applied to the planetary atmospheres, and basically the way it works is if we have a signal transmitted from a satellite, if there's no atmosphere, the signal doesn't bend. If there is an atmosphere, the signal bends, and there will be a noticeable Doppler shift. This is the GPS radio occultation geometry, and again the Leo satellite receives the GPS signals. We can measure this alpha bending angle, and from there we can measure temperature and water vapor. Some characteristics of RO. It has global and local time coverage, very high accuracy and precision, high vertical resolution near 100 meters near the surface. It also has very good total electron content accuracy in the ionosphere. NSF funded UCAR in the early 90s for the GPS MET mission, really to prove the concept. And the plot on the red line is the radio occultation temperature profile, and then we have model and radius on data that match very well. That led to cosmic. The cosmic mission was launched in 2006. We're providing global observations of bending angle, refractivity, pressure, temperature, as well as electron density in the ionosphere. This shows the data flow of the cosmic system. Basically we have data flowing from the Leos down through the UCAR cosmic data analysis and archive center. From here it flows to NOAA, out on the global telecommunications system, to all the global weather centers around the world. Here we see some global coverage of cosmic in 24 hours. Down here we show a plot of occultations per day since the start of the mission, and we've collected over 6 million profiles to date. For weather applications what we really want to do is improve our skill in numerical weather forecasting, and even hurricane tracking intensity forecasting, as well as improving our understanding of atmospheric processes around the globe. This is showing the impact of cosmic on the ECMWF forecast analysis, and basically GPSRO is tied for the second place in terms of forecast impact, despite a small number of observations. Here we're showing the impact of cosmic data on typhoon track error, and basically when we assimilate cosmic data the track error is reduced, and you're seeing that by 24% in this example. In terms of climate, GPSRO is really the world's most accurate, stable, precise thermometer from space. We can evaluate global climate models. We can also calibrate instruments such as radiosons. These plots actually show comparisons of radioson temperature with RO temperature. This is a zero line and the red line is the mean difference, and then we see radioson temperature biases with our data. In terms of space weather we want to observe the global electron density distribution, as well as improve our ability to forecast the space weather with data assimilation, and also understand more about assimilation. The cosmic ionospheric observations are total electron content, which is really the total number of electrons between the receiver and the transmitter. We can use those data also to invert and get electron density profiles, as well as other scintillation information. Here's a movie showing the 4D structure of ionospheric electron density versus latitude and longitude, and the RO data really give you some vertical information on the ionosphere. Cosmic 2 is again a joint US-Taiwan program. We've got six satellites being launched in 2006 in an equatorial orbit, then another six in polar orbit in 2019. This isn't fully funded by the way, but we expect about 10,000 soundings per day. It's really going to revolutionize RO. Here we see Cosmic 2 spacecraft being integrated and tested in Taiwan, and we're going to be launching these satellites on a SpaceX Falcon Heavy launch vehicle. Radio occultation is a proven technology. It's high impact, low cost. We're seeing great impacts on space weather forecasting. We're also seeing great impacts on climate and space weather applications, and with Cosmic 2, we expect this impact to be even greater.