ESRL Global Systems Division

ESRL Highlights NOAA's GPS Contributions to Severe Weather Forecasting

Seth I. Gutman, a Physical Scientist at NOAA's Earth System Research Laboratory, gave an invited talk on "Contributions of GPS Data to Severe Weather Forecasting" to the U.S. States and Localities Subcommittee of the Civil GPS Service Interface Committee (CGSIC) in Savannah, GA on 16 September 2008.

The CGSIC is part of the Department of Transportation's program to respond to the needs of civil GPS users, and to integrate GPS into civil sector applications. CGSIC comprises members from U.S. and international private, government, and industry user groups. Three subcommittees, the International Subcommittee, the Timing Subcommittee, and the U.S. States and Localities Subcommittee, focus on specific user groups. Information from CGSIC members and meetings is provided to U.S. GPS authorities for consideration in GPS policy development and GPS service operation.

Gutman's presentation focused on NOAA's use of the satellite Global Positioning System (GPS) to help improve severe weather forecasts along the coasts of the United States, and especially the inland regions of the U.S. affected by severe weather coming onshore from the Gulf of Mexico. Because of the recent impact of three tropical storms (Gustav, Hanna, and Ike) the discussion concentrated on tropical storms and the attributes of GPS that allow the water vapor associated with these storms to be monitored by NOAA under all weather conditions. The audience consisted of GPS users who routinely exploit Global Navigation Satellite Systems such as GPS for positioning, navigation, and timing, but were largely unaware of the value of GPS for weather forecasting, climate monitoring, and other applications such as satellite calibration and validation. The presentation prompted animated discussion, and a copy of it is available for download at

Gutman combined his travel to include another invited talk on "Tropospheric Signal Delay Corrections" at the NOAA/LSU Workshop on Benefits to the NOAA Community of the National Height Modernization Program (NHMP) and The National Spatial Reference System (NSRS) in Miami, FL on 18 September 2008.

The National Geodetic Survey (NGS) of NOAA's National Ocean Service is working to expand the highly successful Height Modernization Program into a true National Program. The purpose of this is to

    1. provide a comprehensive national system that facilitates the efficient and economic protection, restoration, and management of coastal and ocean resources through a National Datum tied to international standards;
    2. help NOAA understand climate variability and change to enhance society's ability to plan and respond;
    3. help serve society's needs for weather and water information;
    4. facilitate the Nation's commerce with information for safe, efficient, and environmentally sound transportation; and
    5. provide other critical support for NOAA's Mission.

Gutman informed meeting participants about the impact of signal delays caused by the Earth's lower atmosphere on the accuracy of GPS measurements of height and ways that NOAA's environmental modeling program can provide critical information to surveyors to reduce the uncertainty of these measurements and increase the accuracy and productivity with which these measurements can be made. This presentation highlighted how an innovation by NOAA Research to improve weather forecasting, climate monitoring, and other applications can be used by NOAA's National Geodetic Survey to help implement a National Height Modernization Program. A copy of the presentation is available for download at along with an animation that illustrates the variability of the tropospheric signal delay. This animation is available separately at

Contact information
Name: Seth Gutman
Tel: 303-497-7031