11-15 December 1995
SAN FRANCISCO--Rick Anthes, president of the University Corporation for Atmospheric Research (UCAR), will give an invited talk at the American Geophysical Union's fall meeting on a revolutionary new use of the U.S. Air Force's 24 Global Positioning System (GPS) satellites for atmospheric monitoring. Titled "Potential Impacts of GPS Limb Sounding on Weather Forecasting and Global Change Research," (AGU catalog #G22B-3), the talk will be given at 2:00 p.m. on Tuesday, December 12, Moscone Center, Room 307.
In a new program called GPS/MET (for GPS/Meteorology), a low Earth-orbiting radio receiver launched last April aboard the MicroLab-1 satellite uses radio signals from the GPS satellites to gather temperature and humidity data around the globe. A complementary network of ground-based receivers provides additional humidity data from the lower atmosphere.
In his AGU talk, Anthes will compare GPS/MET temperature and water vapor profiles with those obtained from balloon data and gridded analyses from the National Centers for Environmental Prediction. He will present statistical comparisons for more than 1,000 soundings distributed globally and discuss the potential impact of the technology on future weather forecasting and global change research. Expected applications include better weather forecasts, especially over the oceans where data are now scarce, and a means to track climate change by detecting changes in atmospheric temperatures and global water vapor, a powerful greenhouse gas.
In a related talk, Fred Solheim of the University NAVSTAR Consortium (UNAVCO) will discuss "Measurement of Tropospheric Water Vapor along Slant Paths with GPS" (AGU catalog #G21A-11) at 11:30 a.m. also on Tuesday, December 12, Moscone Center, Room 307. Comparisons show that GPS data and water vapor radiometer measurements agree to better than 1 millimeter. Since GPS receivers can track down to 0Á elevation angle, the slant path followed by the radio signals through the earth's atmosphere extends to more than 300 kilometers in the lower 6 km of the troposphere. It is within this layer that 90% of the atmospheric water vapor typically resides. Slant-path water vapor data collected by emerging GPS networks including hundreds of U.S. and thousands of worldwide sites could be assimilated into four-dimensional computer models to improve weather forecasting. Coauthors of the presentation are Randolph Ware (GPS/MET principal investigator), Chris Rocken, and Chris Alber, all of UNAVCO.
Rocken will also present Determination of Total Integrated Water Vapor from GPS, (AGU catalog #G21A-10) ) on Tuesday, December 12, 11:15 a.m., Room 307, Moscone Center. He will discuss design specifications for surface meteorological packages and present precipitable water vapor results computed from the National Oceanic and Atmospheric Administration (NOAA) GPS network on the next day after data collection, using improved GPS orbits from a regional network. Coauthors are Solheim, Ware, and Teresa VanHove, also of UNAVCO.
GPS/MET is sponsored by the National Science Foundation (NSF), National Aeronautics and Space Administration, NOAA, and Federal Aviation Administration. Orbital Sciences Corporation provided the GPS/MET host satellite and launch. Allen Osborne Associates supported the development of the special GPS/MET receiver. UNAVCO and NCAR are managed by UCAR under sponsorship by NSF. Headquartered in Boulder, Colorado, UCAR is a consortium of 61 universities offering Ph.D.s in atmospheric and related sciences.
A wide range of weather and weather-related images is available through NCAR's Visual Communications program. View NCAR's Digital Image Catalog on the World Wide Web at http:/www.ucar.edu/DMC/DMCHome.html or call Linda Carbone at 303- 497-8612 (e-mail firstname.lastname@example.org) or Nita Razo at 303-497-8606 (e-mail email@example.com) for a print version of the catalog or for assistance.
This tip sheet lives on the World Wide Web at http://www.ucar.edu/ucargen/press/AGU-GPS.html