This project, the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), involves research and data management activities centered around an atmospheric measurement concept called Global Positioning System (GPS) Radio Occultation (RO), a relatively new space based active limb sounding method for measuring vertical profiles of atmospheric temperature, water vapor, pressure and height. The fundamental measurement is a time difference caused by bending and delay of GPS radio waves as they propagate through the Earth's charged atmosphere and then through the density gradients of the neutral atmosphere. The elegance and simplicity of the measurement is related to the GPS's purposefully chosen radio frequencies; as unaffected as possible by the intervening atmosphere as they reach the Earth's surface, making them all weather, unaffected by clouds, aerosols, etc. This renewal project builds and continues to improve on earlier work supported by NSF and its partner U.S. agencies, NOAA, Air Force, NASA and Navy, with costs shared equally by the United States and Taiwan, which operate the COSMIC satellites.
Since its launch in April 2006, COSMIC has provided high quality data for science and operational use. The UCAR COSMIC Data Analysis and Archive Center (CDAAC) is currently producing between 1,000 and 1,500 Global Positioning System (GPS) radio occultation (RO) soundings per day. COSMIC data are now being assimilated in near real-time by most global numerical weather prediction (NWP) centers, including the NOAA National Centers for Environmental Prediction (NCEP).
Since its launch, the COSMIC system has produced close to 3 million high quality neutral atmospheric and ionospheric GPS RO profiles and many other valuable data products. These high resolution globally distributed data sets are being used to advance Earth system science by approximately 1,700 registered users from 55 countries, representing major U.S. and international universities, leading operational weather centers, research laboratories, and several private companies.
The work being conducted includes: (i) operation and maintenance of the CDAAC for data processing, quality control, and dissemination; (ii) improvement of the quality and quantity of COSMIC data products by enhancing the GPS RO science payload firmware and CDAAC software processing algorithms; and, (iii) operation of the COSMIC Program Office to support the national and international science communities.
Intellectual Merit: This project has high intellectual merit in that it operates, maintains and improves the state-of-the-art COSMIC radio occultation processing system that provides global, continuous, and all-weather observations of the atmosphere and ionosphere for research and operations. The COSMIC system is providing a gold-standard RO data set. This project will lead to cutting edge advances in system operation, GPS signal tracking, data processing, and inversion techniques to maximize its research value for the atmospheric sciences.
Broader Impacts: The COSMIC data have significant impact on research and operations in the atmospheric sciences because of their quantity and quality, complete global and diurnal sampling, and their ability to penetrate deeply into the lower troposphere. The fact that the COSMIC data are of high precision and accuracy, high vertical resolution, and require no inter-satellite cross-calibration, makes them ideally suited for climate research and instrument validation. COSMIC also provides much-needed ionospheric observations for analysis and forecasting of space weather, and other ionospheric research. This project also has a significant education and outreach component. It will involve graduate and undergraduate students as well as postdoctoral fellows in scientific collaborations, and will continue to organize science workshops and support education and training activities. The COSMIC data and the processing software will continue to be made freely available to the broad university and user community. Beyond COSMIC, these activities will also have positive impacts on planning and execution of future RO missions.
